used at Erowid with the permission of author William White
Last edit: Aug 2002, Erowid.org. Added English Measurement Note to dosage table.
This section discusses some of the effects you might expect to feel if you were to use DXM recreationally (which I recommend against, of course). The effects listed are generally positive, and reflect the results of people who have positive experiences with DXM.
Some people have negative experiences with DXM! For these people, the DXM "trip" may just be several hours of dizziness, nausea, hot flashes, and confusion, with several days of hangover. This is the main reason why most DXM users suggest starting with a first plateau dose.
5.1 What is the General Character of the DXM Experience?
This is a difficult question to answer, because DXM's effects tend to vary widely depending on the person, their set and setting, other drugs, their physiology, and so on. DXM, probably more than most drugs, tends to exert its (recreational) effects in separate stages or "plateaus", rather than being linearly dose-dependent. Within a given plateau, a given set of effects will occur (at a roughly dose-dependent strength). On the other hand, once the next plateau is reached, the feeling may change entirely. A reasonable analogy is water - it exists in three states (solid, liquid, and gas) which all can exist at varying temperatures (e.g., hot water and cold water), but which have different characteristics.
DXM and its metabolite, dextrorphan (DXO), produce different sets of effects. Normally, DXM is converted mostly or entirely into DXO, but with recreational doses, the conversion enzyme (P450-2D6) may saturate, leaving a mixture of DXM and DXO. Furthermore, another of DXM's metabolites - 3-methoxymorphinan - can also block this enzyme, so that taking divided doses leads to more DXM and less DXO than taking a combined dose of the same amount.
DXM's effects are in some ways much more subtle than DXO's. Whereas DXO produces a heavy "stoning" or intoxicating effect, DXM by itself is only lightly intoxicating. DXM, however, can alter the thought processes, leading to highly abnormal, psychosis-like mental states. It is possible that DXM, via sigma activation, may induce a mental state similar to that of schizophrenia. Whether or not this is fun to you is, of course, up to you.
DXM seems to exhibit at least four definable plateaus based solely on dosage, and an additional plateau is notable from a specific dosing regimen (see below, Section 5.9). I previously listed three plateaus; then four; now I'm listing five (although "Plateau Sigma" doesn't occur at dosages higher than the fourth plateau). Evidently, dosages above the fourth plateau lead to full anaesthesia, psychosis, coma, and/or death.
Not everyone notes distinction between the first and second plateaus, or between the third and fourth plateaus. Others suggest that each effect of DXM has a dosage level at which it starts, and (in some cases) a dosage level at which its effects are no longer noticeable (being overpowered by other effects). Some people will disagree with this classification method, but I think this is the best way to represent DXM's effects. Both the third and fourth plateaus have significant dissociative characteristics, much like ketamine.
The most important thing to keep in mind is that the effects in different plateaus are often very different. For example, on the first plateau, DXM tends to have a stimulant effect. Upon reaching the second plateau, however, the stimulant effect may no longer be present.
The beginning of the comedown off of a DXM trip can come abruptly. Often, the user will know when it's starting to end by noticing the return of normal sensory processing. Coming down from there may take a significant amount of time. A second DXM trip too soon after coming down is not a good idea due to the potential for side effects and psychotic episodes (227). Wait at least three days and preferrably two weeks between each DXM trip.
The following table can be used as a general guideline for the plateaus. For convenience I give example dosages in gelcaps and 3 mg/ml syrup for 75 kg and 150 lb adults; adjust up or down by the amounts indicated per 10 kg or 25 lb. Calculating with the mg/kg is more accurate, but it's easy to make mistakes when using non-metric measures. These dosages are as DXM hydrobromide.
Dosage will vary considerably from person to person, by as much as 5 times! Also, these mg/kg figures should evidently be adjusted down for higher mass (e.g., maybe 6 mg/kg to 13 mg/kg third plateau for a 150 kg adult). Note that kg = pounds * 0.45.
I have included a new category in this table: "Usenet Suggestions". This is a combination of suggested dosage guidelines from Usenet, and may more accurately represent the plateau dosage of DXM in regular users (the original plateau levels were based mostly on occasional users).
|Dosage Range (mg/kg)
|Usenet Suggestions (mg/kg)
|Gelcaps (30 mg) for 75 kg adult
|4 to 6 gelcaps
|6 to 18 gelcaps
|18 to 37 gelcaps
|Adjust per 10 kg
|1/2 to 1 gelcap
|1 to 2.5 gelcaps
|2.5 to 5 gelcaps
|Gelcaps (30 mg) for 150 lb adult
|3 to 5 gelcaps
|5 to 17 gelcaps
|17 to 34 gelcaps
|Adjust per 25 lb
|1/2 to 1 gelcaps
|1 to 2.5 gelcaps
|2.5 to 5.5 gelcaps
|Syrup (3 mg/ml) for 75 kg adult
|37 to 62 ml
|62 to 187 ml
|187 to 375 ml
|Adjust per 10 kg
|5 to 8 ml
|8 to 25 ml
|25 to 50 ml
|Syrup (3 mg/ml) for 150 lb adult
|2 tbsp to 2 oz (1/4 cup)
|2 oz to 5.5 oz (2/3 cup)
|5.5 oz to 11 oz (1 1/3 cup)
|Adjust per 25 lb
|1 tsp to 2 tsp
|2 tsp to 1 oz (1/8 cup)
|2 tbsp to 2oz (1/4 cup)
|English Measurement Conversion
|1 cup = 8 oz = 16 tablepoon (tbsp) = 48 teaspoon (tsp)
The specific effects at each plateau will be listed according to the following categories: Sensory, Cognitive/Emotional, Motor, and Memory. Additionally, the lower two plateaus are considered together, as are the upper two plateaus.
5.2 Overview of the Lower Plateaus
The four dosage plateaus can be divided into two groups based on a certain degree of similarity: the lower plateaus and the upper plateaus. The lower two plateaus share many features and some of these will be considered here. A generalization would be that the lower two plateaus are more "recreational" than the upper plateaus. Specifically, they have considerably less hangover, do not generally involve serious disruption or breakdown of sensory processing, and are more similar to other intoxicants.
DXM in the lower two plateaus has been compared to a cross between MDA and alcohol. It tends to intensify emotional responses and feelings of meaning from external events. At the lower plateaus there is usually enough motor control to be able to engage in physical activites (although, like MDMA and MDA there are reasons why you may not want to, including dehydration and overheating).
Most find sensory input is still understandable, although there are peculiar changes which will be discussed below (notably flanging). At the lower plateaus it is still possible to interact extensively with the outside world, and one can watch and follow reasonably complex plots in movies, and have complex conversations.
Although DXM is in many ways not a good "casual" drug most people have used it without adverse effect at the lower plateaus. Interestingly, many people who have use DXM at the upper plateaus eventually find that the lower plateaus no longer offer much enjoyment. There are a lot of potential reasons for this (see Section 7.6); I think most of it is simply that DXM at the upper plateaus changes one's expectations about its effects and gives one familiarity with its memory inhibition.
5.3 The First Plateau
The first plateau generally occurs around 1.5 to 2.5 mg/kg (some net users suggest 2.7 mg/kg as ideal for regular users), but this may vary enormously depending on metabolism and other factors. The first plateau is probably the hardest to hit; many people "overshoot" it. Please keep in mind that these effects listed are general effects, and that individual results may vary considerably.
A general narrative of the first plateau can be constructed. At about 30 minutes to 1 hour after dosing, an "alert" sensation is noticeable; this is simply a feeling that is unique for individual and signals the begin of altered consciousness. The experience has only a vaguely "drug-like" character for about 10 minutes, after which restlessness and slight stimulant effect are noticeable. After another 10 minutes or so, movement and position sense are altered; those with motion sickness begin to notice nausea. Gravity starts to feel weird, and one may bounce around a lot. Emotions may start to become intensified. There is a slight feeling of dissociation from reality, but overall the experience is slightly intoxicating, with intensified emotions and sense of importance from everyday events. This effect peaks and then slowly subsides until it is unnoticeable.
A first plateau trip usually takes between 20 and 40 minutes to start (on an empty stomach), peaks about 1.5 to 2 hours later, and lasts between 4 and 6 hours. Gel capsules take up to 1 hour additional to dissolve. Hangovers are very rare from this plateau, but if they do occur, they tend to consist mainly of lethargy.
The primary effects of the first plateau are general euphoria, euphoria specifically linked to music and motion, slight disturbances in balance, moderate stimulation, and very slight intoxication. The intoxication and balance disturbances are similar to that induced by alcohol, but much weaker and without the mental confusion; there is little if any mental sluggishness or confusion with a first plateau trip.
Some people have difficulty hitting the first plateau. It can take several trials; as a general guideline, if you notice double vision, you've gone way too far. A lot of the more pleasurable first plateau effects, in particular the music euphoria, are set and setting dependent. Being in good physical condition, avoiding excessive caffeine, and being in a good mood are all important factors in achieving a good first plateau dose.
Positive first plateau experiences are one of the first to go with regular use. Part of this seems to be tolerance (which builds quickly and lasts for considerable time). Another part seems to be a familiarity with the first plateau experience; after awhile it no longer seems quite so profound or interesting. Some have suggested changing set and setting as a way of regaining the more interesting aspects of the first plateau.
5.3.1 Sensory Effects
Most of the effects of the first plateau relate to the senses. The best known, and probably the most responsible for first plateau use of DXM, is the effect upon hearing (specifically upon music). Sounds may seem "richer" or "deeper", and music in particular is affected (the difference between listening to music on DXM versus sober has been compared to the difference between music in a concert hall versus on a cheap radio). In addition to the change in the nature of hearing itself, music can bring a sense of euphoria, often quite intense. In comparison to the positive effects on music reported by some users of cannabis, the DXM music effect is usually characterized as much "speedier".
The type of music with which this effect most strongly occurs will tend to vary from person to person. Rave music is one of the most commonly affected, possibly due to the regular beat (at higher plateaus especially, much of DXM's sensory effects seem beat or rhythm related). Classical and Celtic/folk also seems to be popular. Really, though, the strongest indicator of personal response to a given piece of music seems to be 1) that the user enjoys it, and 2) that it has an "intense" or thematic quality.
Not everyone notices this effect. Some notice the opposite -- DXM makes music seem less impacting, and bass tends to be attenuated, leaving everything sounding "tinny" and distant. There does not seem to be any factor predicting whether DXM will improve or degrade the musical experience.
Visual effects are not particularly strong at this plateau. If present, they usually consist of motion trails (as if afterimages of each "frame" of vision were not clearing quickly enough). There may be some deterioration of stereoscopic vision (and thus depth perception). Colors may seem slightly more vivid. Some have remarked that peripheral vision seems to be degraded.
Taste and touch do not seem to be appreciably affected, although some users have reported that taste is enhanced and mildly euphoria-linked. Others have reported the same effect for touch. The sense of smell, on the other hand, is improved for some; in fact, some find scents so overpowering that they cannot remain around scented items.
Balance and body position sense can be significantly affected, ranging from a mild disturbance (some call it "sea legs") to a near total loss of position and balance sense (generally this only happens on upper plateaus). The changes seem to relate to an anesthesia of the body senses in particular. The effect (like the other sensory DXM effects) can be euphoric; some users like to roll around, do cartwheels, dance, march, whatever. People who are very susceptible to motion sickness seem to report nausea, but most do not. Overall some have described these effects as like free-fall.
5.3.2 Cognitive/Emotional Effects
Even though DXM has a slight "stoning" or intoxicating effect on the first plateau, there are surprisingly few deficits of cognitive function. Language is the most strongly affected, although these effects are usually limited to occasional word and syllable repetition (especially in already-repeated syllables, e.g., "banana" to "banananana"), spoonerism (e.g., "share boulders" instead of "bare shoulders"), and difficulty coming up with specific words (the "Tip of the Tongue" phenomenon).
Some users report that they feel more creative and capable of non-linear thought on DXM, and this seems to be maximized on the first and second plateaus. Whether this is, in fact, true, or just seems true because of the drug, I have no idea; to my knowledge there are no studies on this. Another cognitive characteristic that occasionally occurs at the first plateau (but more commonly at the second) is that things can seem much more interesting, or at least much less dull and boring, than they usually are. There may be an overall increase in approach-related behavior.
Many DXM users report a moderate to strong stimulant effect at the first plateau, which disappears at higher dosages. This seems to be enhanced by caffeine. One user reported being able to stay up for 48 hours by maintaining a first plateau level. (Note that I don't recommend this).
Another characteristic of first (and second) plateau trips is a lowering of inhibitions related to conversation (and to a lesser degree to behaviour). Many people find they can discuss painful or embarrassing topics without difficulty. This is usually described as a very positive effect, and those who have experienced it often state that they feel more comfortable with themselves after the trip. Some have reported a strengthening of friendships due to this effect. It's interesting that as the third plateau is approached, recall and discussion of such topics seems to become more and more "mandatory".
A few people seem to have problems identifying abnormal behaviour, and some have gotten themselves into awkward social situations by saying (or, rarely, doing) exactly what they mean. Dissociatives do seem to inhibit the ability to unconsciously recognize and act based upon social constructs. My personal feeling based on some observation is that if you are consciously aware of your behaviour you are not likely to have problems; it is those who act primarily out of instinctual adherence to social rules that tend to behave somewhat bizarrely.
Mood enhancement is the most regular emotional effect of the first plateau; many people find themselves fairly bouncy and happy, occasionally euphoric. Unlike many drugs, there is not usually much "let-down" when the trip ends. Fear is rare at the first plateau. There may be a sense of energy or drive.
The effects upon libido evidently tend to vary from person to person. Some people report an increase in sex drive; others find that playing, physical contact, music, etc., seem much more interesting and enjoyable than sex. The effects on sexual performance itself are not very strong at the first plateau, though males may have some difficulty in achieving orgasm. When orgasm does occur, it is often accompanied by extreme muscle tension and profuse sweating. Note that there may be problems with hypertension from sex on DXM.
5.3.3 Motor Effects
Another identifying characteristic of a first plateau DXM trip is its effect upon motion and motor skills. Users tend to walk and move in specific ways (varying somewhat from person to person) characterized by large, fluid movements. In fact, it may be difficult to perform small or abrupt motion. Motor tasks initiated may continue beyond their targets (this can range from fun to distracting). To an outside observer, this can seem quite strange, especially the changes in gait. It is possible, however, to move normally.
These changes may be related to euphoria- linking of body kinetic sense (see Sensory Effects, above) which would make large and sweeping motions more enjoyable. It is also possible that something more directly involved in the planning and carrying out of complex motor tasks may be at work, and that the euphoria is simply a general phenomenon which is not directly connected to the alterations in motor skills. Some have suggested that impaired processing of vestibular signals (i.e., those from the middle ear which relay position and motion information) may be involved. Activity of DXM in the cerebellum may also contribute.
5.3.4 Memory Effects
The memory effects of a first plateau trip are slight but usually noticeable. Most of the effects probably come from a general deterioration of short-term memory. Working memory (the "train of thought") can become stuck in repetitive thoughts; other times it can be very easy to become distracted. Recall of events prior to the trip does not seem to be degraded. Encoding (i.e., making new memories) may be worsened, so that after the trip there is some difficulty in recalling events during the trip. Also probably because of the deterioration of short-term memory, it may be easy to lose track of time.
[erowid note: The sections on memory discuss only memory effects during the acute effects of DXM ingestion and are not describing any lasting aftereffects.]
5.4 The Second Plateau
With the second plateau (around 2.5-7.5 mg/kg, 6.4 mg/kg suggested from regular users) several new effects become evident. The most profound is that DXM begins to take on a heavier "stoning" characteristic, and senses and cognitive function are affected accordingly. Closed-eye hallucinations start for some people on the second plateau. Some of the first plateau effects, e.g., the music and motion linked euphoria, may diminish or stop entirely.
Second plateau trips usually take between 30 and 60 minutes to start (on an empty stomach), peak about 2 to 3 hours later, and last about 6 hours. Again, gel capsules take up to 1 hour additional to dissolve. Hangovers are not common with lower second plateau trips, but some people experience them.
A general narrative of the second plateau: The trip beings identically to the first plateau trip, although the alert and early effects may be noticed earlier. After passing to the music and motion euphoria stage, the first plateau sensations begin to be overshadowed by disruptions in sensory processing, as sensory input begins to get "choppy". Both sight and sound take on a dreamlike characteristic and one begins to feel increasingly detatched from the outside world. There may be bursts of sensory deprivation where the outside world seems to go away, but overall one maintains contact (somewhat incoherent) with the outside world. After a few hours of an overall "stoned" feeling, the sensations begin to subside. A slight hangover consisting of lethargy may be noted the next day.
5.4.1 Sensory Effects
The most general sensory effect of the second plateau is "flanging". Flanging, also called phlanging, phasing, stop-action, framing, strobing, etc., is the sensation that continuous sensory input has been chopped up into frames (as if you were watching a badly animated cartoon), often with some echo effect of each frame. There does not seem to be any loss of sensory content; instead, it is as if the ability to keep sensory input time-continuous were disturbed. The best analogy from other drugs may be the effects of nitrous oxide upon sound. The best analogy from non-drug experiences is listening to a voice through an echo/delay effects box (which is where the term "flanging" comes from).
An interesting and probably associated sensory phenomenon is that it seems as if one is aware of several temporal stages of sensory processing all at once. In other words, a sentence may be heard not sound for sound or word for word, but all at once (this is difficult to describe). Similarly, visual images may be jumbled together with previous images. This may be due to an excessive persistence of sensory buffering.
Vision in particular is changed on this plateau. Depth perception is often lost, and the ability to keep both eyes focused on the same thing is diminished (leading to slight double vision). This is most noticeable in people without a dominant eye.
Sound, as already mentioned, tends to be flanged. With the sense of touch, there is not necessarily flanging so much as a noticeable delay between the stimulus and recognition of it. Pain especially tends to be somewhat dissociated. Taste is usually simply dulled. Many people report a vastly improved sense of smell though some report that it is dulled as well.
The sense of balance is severely disrupted, as is body position and kinetic sense. Keep in mind that dissociation of pain and the disruption of body sense together make physical exertion somewhat risky, as it is possible to over-exert and not notice.
Closed-eye hallucinations tend to begin at the second plateau (and in fact are the reason I distinguish this from the first plateau). Usually these are not "true" hallucinations, but instead are considerable enhancement of imagination, up to fully eidetic imagery (i.e., you experience lucidly what you imagine). This is especially powerful with memories; some users are able to re-experience past events, or "simulate" future events, as if actually there, interacting with the environment (I call this the "Holodeck Effect"). Many users report this to be quite useful for introspection.
Actual hallucinations, if they do exist, tend to be abstract and cartoon-like. There seems to be an emphasis on linear structures - long, thin lines, or long queues of simple objects. There may also be Lilliputian hallucinations (everything seems either way too big or way too small, or both). Some people find considerable similarity with fever hallucinations; this can be unpleasant.
Your experiences throughout the day will influence the hallucinations you see and the imagery you can create. For example, if you have spent the day playing DOOMTM, your hallucinations are likely to involve scenes and elements from the game. Eidetic imagery works a little different - you can conjure up images, but they are likely to have a "DOOMTM-esque" feel to them (bitmapped textures, ugly walls, etc.). This is an interesting effect, and my hunch is that DXM hallucinations and imagery may be very dependent upon what's already stored in intermediate term memory. So it might be worth planning the events of the day with your trip objectives in mind. This may also be possible to some extent during the trip itself; e.g., if you want to imagine yourself in space, go to a planetarium.
5.4.2 Cognitive/Emotional Effects
Higher reasoning is still not appreciably affected at the second plateau; in fact one of the more interesting aspects of DXM at the first and second plateau may be its ability to disturb one function of the mind while leaving another almost untouched. On the other hand the content of one's thoughts may become increasingly abstract as the outside world is ignored.
An interesting cognitive effect that is pronounced at the upper second through the third plateau is a change in self-referential thinking. Self-referential thoughts or ideas (e.g., "this statement is false") may seem both more understandable and more profound, both in the abstract and on a "gut level". Thoughts can, in fact, get quite abstract, sometimes to the point of seeming meaningless to other observers. Quite a few people have reported some sort of self-referential or abstracting aspect to thoughts, such as a "self-creating and self-invoking meme" that consists of the concept of itself. Another example is abstracting the concept of abstraction (and abstracting that, and so on and so on). There may be an overall blurring together of cause and effect, and causality may become an alien concept (I've spoken to more than one quantum physics student who enjoyed DXM).
Language becomes difficult, partly due to cognitive changes (as in the first plateau), and partly due to difficulty in coordinating the mouth and tongue motions. There may also be a direct effect on the language-producing centers of the brain. Interpreting spoken language is difficult due to sensory flanging. However, thinking in language is still fairly easy.
The curious detachment from painful or embarrassing topics of conversation that occurs at the first plateau continues and is much stronger at this plateau. Again, this is generally viewed as a positive event, although if you're not prepared to encounter and possibly discuss your deepest, darkest secrets, you might want to avoid higher doses until you're comfortable with DXM.
Another major defining characteristic of the second plateau (as well as closed-eye hallucinations and flanging) may be the motivational aspect. Repetitive, mundane, boring tasks suddenly become doable, and (if one can avoid distraction) may be easily accomplished, even if they take hours. There may be a considerable behavioural stimulant effect remaining at the second plateau without other feelings characteristic of stimulants. The euphoria from the first plateau continues but diminishes as dosage across the second plateau increases.
5.4.3 Motor Effects
The first-plateau effects on motor skills continue to exist, and may be considerably stronger. Some users find themselves contorting their limbs into rigid positions (and in some cases with general muscle rigidity), others may extend and stretch themselves. These effects are not always immediately apparent; when they are, the user usually reports that it just "feels right" to be in that position. It is still possible to override this.
Another accentuation of first-plateau motion effects that sometimes occurs is that the large, sweeping motions, once initiated, may continue for considerable time (looking somewhat like a cross between modern dance and Huntington's disease). Again, it just "feels right" to do.
5.4.4 Memory Effects
Intermediate-term memory and working memory may be severely disturbed, although experience with DXM seems to help people compensate. Possibly because of the changes in memory, it may be very difficult to get bored, even with repetitive tasks. At this plateau, a lot of time may get lost, and the more mundane aspects of the trip are easily forgotten after it is over.
5.5 The Transitional Phase
Between the second and third plateaus lies a transitional phase. Not everyone experiences it; it seems that about 70% of DXM users have reported at least one aspect of it. In some senses it seems to be "programmed", in that the content of the experience, although varying from individual to individual, does not change much from one trip to another.
Overall these experiences are probably the crossing of a threshold in dissociation. The hypothesis is this (although it is by no means proven). Generally speaking, sensory input competes with "feedback" input from the brain (you've probably noticed this from being deep in thought and not noticing what is going on around you). As sensory input becomes sufficiently inhibited, networks where sensory and feedback information are combined and reconciled begin to gain a larger and larger proportion of their input from internal feedback sources. Eventually, there is enough attenuation of sensory input (and probably intermediate-term memory as well) that the feedback loop becomes "free-running", leading to internal states (or models, if you prefer) that are increasingly detatched from the outside world.
During this time, people generally report that they can experience the process or they can discuss, relate, write about it; it does not seem possible to experience it while attempting to maintain contact with the body in any way. Unfortunately, memory of the experience is often impaired, so one gets the feeling of having taken an incredible ride without remembering it. Fortunately, the threshold experience may repeat itself throughout upper plateau trips (see Section 8.2.1).
If you want a very rough model for the threshold experience, get a video camera and a television, and feed the output of the camera into the TV. Point the video camera at the TV, turn on the date display on the camera (to provide some sort of "sensory input"), and turn the brightness down on the TV. Adjust the zoom on the camera to roughly include the entire TV screen. You will notice one or two copies of the date/time digits appearing, but overall the picture still looks like a video of a TV screen inside a screen (or two).
As you increase the brightness on the TV, however, something interesting begins to happen. Eventually, the feedback becomes self-sustaining, and you can get extremely complex, self-reinforcing patterns which take hold and maintain themselves. The entire picture begins to turn into abstract blobs and colors. As you adjust the zoom, you will find a stable point where you can wave your hand in front of the screen and the effects of this "sensory input" will ripple through the system, mutating constantly but never really leaving. This also makes a fascinating trip toy, by the way.
Overall there are some common features to most people's threshold experiences. The first is a sensation that has been described as the opening of nasal passages, being full of helium, losing one's body, or having one's heart stop beating. The actual effect is most likely a sudden cutoff of sensory input from within the body - everything from all the little aches and pains to the awareness of one's own heartbeat go away. This can be very disturbing if a naive user interprets it as heart failure!
The second transitional effect is a temporary loss of all sensory input (this does not always occur), as if one were in a sensory deprivation tank. This is often accompanied by severe Lilliputian hallucinations, probably because there is no internal size reference (since the rest of the universe has just gone away). One person reported feeling as if he shrunk down to the size of a proton, and the rest of the world were light-years away.
This transitional phase often repeats itself between the third and the fourth plateaus.
5.6 The Upper Plateaus
The upper plateaus are considerably less "recreational" than the lower plateaus, and are more introspective, spiritual, and shamanic. Most people who use DXM for psychonautical exploration or spiritual work do so at the upper plateaus. The upper plateaus generally take more out of the user, with more frequent hangovers and moments of dysphoria.
Unlike the lower plateaus, most upper plateau experiences do not lend themselves to moving around much. Most people find it better to find someplace comfortable and stay there. Trying to move too much can induce nausea in some people.
5.7 The Third Plateau
The effects at the third plateau itself tend to be very intense, and often very different from earlier plateaus. Keep in mind that a third plateau trip can be terrifying to people who are not psychologically comfortable and prepared. Because the third plateau is so individually variant, I don't feel comfortable in trying to come up with a narrative.
5.7.1 Sensory Effects
The flanging of visual effects, coupled with the loss of stereoscopic vision, becomes so strong that the brain seems to completely give up trying to process vision, leading to a sort of "chaotic blindness". Simple images (e.g., a candle flame) are still recognizable, although given the loss of stereoscopic vision one tends to see two of everything. More complex images, especially images that are not sharply defined, are difficult if not impossible to recognize. Vision, when possible, has a very dream-like quality to it.
Simple sounds are still understandable, and one can usually comprehend language, although it may be necessary for the speaker to phrase it in a complex rhythm (see Section 5.7.2). Music euphoria is rare. Touch and taste are subject to considerable anesthesia, and pain especially may be completely dissociated (it's still there, it just doesn't seem to apply). Body position, kinetic, and balance senses are similarly disrupted.
Some people continue to report an enhanced sense of smell on the third plateau; in a few people almost all smells are overpowering, and subtle elements of scents may be recognizable. This can affect taste, and ordinary foods or drinks can take on peculiar tastes as previously unknown odors are noticed. Even the type of container can affect the smell, with faint scents from paper cups, plastic, and even metal noticeable.
Hallucinations may continue, although they tend to be more abstract and "pre-sensory" rather than being predominantly visual. Oftentimes there is an overall sensation of being surrounded by "grey-ness", which brightens to white light as the dosage increases. There do seem to be more frequent moments of "virtual world" experiences, where one can construct an imaginary sensorium with the eyes closed.
At the third plateau, the flanging of sensory input occurs both on a raw level (sounds, images) and on higher levels (words, phrases, faces, etc.) This is, to my knowledge, unique to DXM. Flanging may slow down and speed up, leading to periods of lucidity alternating with periods of semi-consciousness.
5.7.2 Cognitive/Emotional Effects
Cognitive function becomes severely disrupted at the third plateau. Complex tasks, such as arithmetic, may be very difficult (though some report little or no difficulty with simple skills). Reaction time is significantly delayed. Decision-making is somewhat degraded, although conceptual thought is less affected than concrete thought. Generally speaking, mental tasks which do not require changing context are far less impaired than tasks which require one to change one's decision-making approach.
Those who study this sort of thing will be interested to know that I have done some preliminary tests which show impaired results on the "Brain Warp" toy in "combo" mode (which is a basically a simplified Wisconsin Card Sort for kids). This probably indicates impaired prefrontal lobe function, a hypothesis supported by some research (226,326).
Language changes can be quite significant. Sentences may stretch on and on, or alternately be very terse (I call this the "Hemingway Effect"). Words, syllables, and phrases are commonly repeated. This may be related to problems with working and short-term memory. Speech may occur in a very rigid (but not necessarily simple) rhythm, and the user may not respond to speech unless it is in a similar rhythm.
The normal "chatter" that goes on inside everyone's brain tends to slow down or stop at this plateau, leaving a feeling of mental peace and quiet. One person reported this as "it felt like the top of my skull was opened into a clear blue sky".
Mood can range from absolute mania to panic. Many people have independently reported feeling as if they were dying, with some sense of fear, although some people do not seem to associate fear with this. Some people report a great increase in approach behavior, as if every event and object were a new experience; others find irrational fears occurring (possibly due to body load).
Panic attacks have occurred at the third plateau. This can be a scary experience, especially if one finds one's heart rate skyrocketing due to the panic attack and doesn't know why. The best way to cope with this is to try and calm down, much the same as one would with a bad trip on any other hallucinogen.
DXM on the third plateau has a very "shamanic" feel to it. Part of this is due to the sense of rebirth, part from the recall of suppressed and/or partially forgotten memories (some similar effects which I formerly placed on the third plateau (e.g., feelings of contact with other beings) I now place on the fourth plateau as they tend to occur at substantially different dosage levels). Complete annihilation of self can occasionally occur (rarely up to the point of forgetting one's identity, but more commonly just psychedelic ego-annihilation).
Note that, to sober observers, the effects of a third plateau trip can seem very unusual and unpleasant (often much more than to the person tripping).
5.7.3 Motor Effects
At the third plateau it may be impossible to perform coordinated movements. The large, sweeping motions of the first and second plateau are no longer present. Instead, many users lack both the desire and ability to move at this plateau.
Well-learned motor tasks (e.g., speaking and typing) are still possible at this plateau, provided the user doesn't attempt to think about them. In particular, some users have reported that they were able to express their thoughts via typing, without even thinking about it or realizing they were doing so; however, when they looked at the screen or keyboard, they were no longer able to type. This is evidently a phenomenon unique to dissociative anesthetics.
5.7.4 Memory Effects
Short-term memory is seriously impaired; working memory is less impaired. Thoughts may get stuck in a loop. Memory encoding of the more mundane experiences of the trip tends to be very bad; expect to forget a lot of the trip itself (a few people report that they begin to recall events from the trip a few days after it has ended; I know of no mechanism for this). The sense of time can be quite distorted, both in terms of chronological placement of events and in the sense of the passage of time.
The day after a third plateau DXM trip, some users feel as if there were a break in the continuity of their memory, almost like the close of one chapter and the beginning of another. Some find this a very positive feeling, like a rebirth or rite of passage. It can be disconcerting if experienced without adequate foreknowledge and preparation.
One of the most significant memory effects that can occur at the third plateau is the spontaneous recall of memories, often memories which were hidden (consciously or not). This can be a positive experience if one is prepared to review the darkest secrets of one's past; otherwise it range from somewhat embarrassing to very unpleasant and disturbing. The user may also feel compelled to tell her or his companions about these memories (not always a good idea).
5.8 The Fourth Plateau
Information pertaining to the fourth plateau (roughly, above 15 mg/kg) is limited, and what I have gathered will be presented as a general overview. Fourth plateau doses are similar to fully dissociative (but pre-anaesthetic) doses of ketamine.
Please note that dosages in these ranges are approaching the danger zone, and under no circumstances should anyone take this much DXM without a sober assistant who can take you to the hospital if the need arises! Many people neglect "trip sitters" with psychedelics. While you can probably get away with this with LSD (provided you remain in control enough not to do something stupid), with DXM there may be moments of such total confusion that you can wander into trouble without knowing what's going on. Additionally, the danger of adverse physiological effects, although not great, is worth paying attention to. Finally, psychotic breaks are most frequent at fourth plateau doses (and of course increase as the dosage increases).
Generally, people entering the fourth plateau report that they lose all contact with their bodies, often suddenly. This can be somewhat frightening. In particular, the sense of breathing is one of those missing, and people have occasionally interpreted this as evidence that they were dead. The surrounding environment may be evenly colored (usually grey or white), or it may appear vividly realistic, or cartoon-like, or anywhere in between these.
Many users have reported experiences very similar to "out of body" and "near death" experiences. In such cases, many report that they have contacted other beings, whose reaction to the user is usually somewhere between curiosity and amusement. Contact with "superior being(s)" has also been reported, sometimes as a raw force, sometimes personified in some way. In the reports given to me, the "superior being" image is more often female than male.
Delusions can become fairly involved at this plateau; the crucial factor seems to be whether or not the individual realizes that the belief or thought is drug-induced. Some people, especially those more experienced at this level, have reported that although they were aware that their thoughts were delusional, they didn't really care at the time. In general these delusions are fairly harmless (e.g., "I am a flower in the middle of a field").
Typically an individual in this plateau won't be moving at all, which can be frightening to observers. In many ways this state resembles dreaming. If someone in this plateau does attempt to move, his or her attendants should be very sure that he or she is conscious of these actions, and not responding to a delusional environment.
Somewhat surprisingly, many cognitive abilities are still intact. Basic computational skills and long-term memory recall do not seem to be particularly affected. It is also possible for the "body" (actually body and some parts of the mind) to undergo fairly complex tasks while the conscious mind is dissociated.
One individual wrote the following of the fourth plateau trip, and I think it is a good explanation both of the trip and of its possible origins:
I've come to the conclusion that DXM is almost unique in it's ability to create a truly "alien" experience - one in which major aspects of one's humanity can become entirely irrelevant. Most obviously, one's body can be left behind; even forgotten. The experience of becoming or encountering bizarre life-forms seems at least somewhat common, as are weird, horizonless landscapes or space-scapes. I think alot of this "alieness" comes from having so many of one's ties to the familiar severed. When your body is gone, your mind loses its sense of how "big" or how "small" you are in relation to your surroundings. Hence hallucinations of huge things like galaxies, or of being as large as a mountain, as small as an atom, etc. I think the brain also misses subtle clues like the sensation of breathing, blood flowing through the veins, etc. - things which help remind you that you're human. And at some point, even your memories of the familiar may be suppressed.
5.9 Plateau Sigma
A few people have independently contacted me about an additional plateau -- one reached not by increasing the dosage but by prolonging the experience. I searched for some time for a name before settling on "Plateau Sigma", both because it seems to be related to sigma activity (see Section 10.2) and because it occurs as one sums up small doses (sigma being the mathematical symbol for summation). This summation may lead to a strong potentiation of the psychotomimetic effects of DXM (227). Over half the people who had a Plateau Sigma experience have said it was extremely unpleasant and that they would never repeat it.
The most commonly reported dosage regimen for Plateau Sigma is given below. However, before giving it, I warn you strongly against making this sort of attempt. DXM at high dosages is probably hard both on the brain and the body, and extending the experience is likely to increase the chance for dangerous side effects. Furthermore, one must be experienced enough with DXM, with the psychedelic experience in general, and with one's own mind, to be able to understand the experience. Everyone who has reported a successful experience with this dosage regimen has been at least 23 years of age. While I do not doubt that some younger people may be capable of having a good experience at this plateau, most seem to be unable to understand it and unable to control it, and there may be a real danger of psychotic breaks. Finally, the experience is in some ways acutely uncomfortable, as one's contact with inner and outer reality seems to break down entirely.
Combining suggestions from others I have come up with the following dosage regimen. Start relatively early in the day (the experience degrades if one is too fatigued), at about 6 to 10 hours after awakening. It helps tremendously if one is in good physical shape and not under emotional stress. Take a low second plateau dose. In three hours (or about 1 hour after the peak), take a second low plateau dose. At three more hours (or, again, 1 hour after second peak) take a high second plateau or low third plateau dose. After coming down from the third plateau, instead of going back to the second plateau and down to baseline, you may be left in Plateau Sigma. Drugs which inhibit cytochrome P450-2D6 seem to enhance the duration and intensity of the experience. Nicotine is reported to inhibit it, and may even prevent it entirely.
At Plateau Sigma interesting things happen to reality. Some have reported vivid, entirely realistic contacts with alien entities, spirits, gods and goddesses. Unlike the fourth plateau, these contacts often take place with eyes open, immersed in everyday reality. Although none of the people who reported these experiences to me had bad trips, most related that the experiences were so real that they felt they easily could have.
Vision suffers a curious change, seeming to consist of well-processed but highly strobed images; so strong is the effect that it seems as if one is looking at the world under a fast strobe light. The eyes don't seem to track in synch with the inner 3D model of the world, so that when one looks to one side or another, the world lurches back and forth for a moment. Interestingly, it almost seems as if one is looking at the world from an inner vision with the eyes closed (see Section 5.11).
Finally, thoughts can be totally deranged. Connections between entirely unrelated ideas form, causality goes out to lunch, and one's personality seems pretty much dissolved into the universe. Expect to hear a lot of voices; some people find themselves totally obedient to them. There seems to be a "tireless" quality to the experience, as if one does not feel either fatigue or emotion directly, but only receives information from the inner voices ("sit down now, you're tired"). There are interesting comparisons both to accounts of acute schizophrenia and to Jaynes' postulated bicameral mind (350).
Again, let me warn you of the dangers here. You are probably stepping head first into psychosis, and unless you've got a very good trip sitter, you might end up coming back to reality in a padded room. Or, if you're really unlucky, you might freak out, have a hypertensive crisis, and end up in the hospital. Chronic high-dose use of PCP has been implicated both in deterioration of some brain areas and in cerebral hemorrhages. While PCP stands somewhat alone among dissociatives due to its additional and peculiar pharmacology, one should always be cautious when blazing trails in uncharted territory.
One last time: Be Careful!
5.10 Is There Anything Beyond the Fourth Plateau?
There may be yet another plateau beyond the fourth. One individual took 3000 mg (I don't know his weight) and survived, although he regained consciousness in a strange location and remembered nothing of the trip. Beyond the fourth plateau probably lies full anaesthesia, then respiratory collapse, coma, hypoxic brain damage, and death. Given the toxicity of DXM at doses much higher than the fourth plateau, I don't think anyone should try and go there. You might not be able to come back.
More recently, one user accidentally went beyond the fourth plateau and had a rather unpleasant (to say the least) experience:
Now, and interesting experience to relate. several months ago, I accidentally took 3060 mg of dxm, which at my weight then of 150 lbs, translated to about a 46.6 mg/Kg 9I believe) dose.
Now, I won't go into the details of how I managed to take this much, but in a nutshell, I took 1100 mg and three hours later felt nothing, so I took another 900 mg. Then, once it hit me, I somehow cleaned out the rest of my stash, for what reason, I don't know.
Anyway- for the first 6 hours following my first dose, I felt normal. Then, I experienced a normal high 2nd trip until the point when I took the remaining 1060 mg. After that point, i recall the following things:
- falling face down on the floor in my room.
- wondering why my rug tasted like burned nylon, when it was cotton.
- feeling myself float past the 3rd and even 4th plateaus, they were clearly defined for me, with differing emotions and feelings for each one. The last thing I remember before passing out was looking up and seeing a 5th plateau, which was very dark and most definitely not happy looking. :) Then darknss.
- dropping in and out of consciousness for a period of 15 hours, while hearing the voice of what I thought to be some higher being telling me repeatedly "do not do this to me again"
Approximately 25 hours after the first ingestion, I woke up, for the first time realizing where I was and what I'd done. I crawled to the bathroom, and found I'd lost about 4 lbs due to sweating, and was severely pale and shaky. I crawled back to my room, and found the floor absolutely soaked with sweat, which smelled like coricidin. I then passed out again, and woke up 6 hours later completely refreshed, but with a slight stomachache. I grabbed come chocolate milk and that gave me some energy back. Enough to reflect, at least. It was then that I counted the empty foil wrappers and learned what I'd done. I laid back and thought about this, and couldn't remember much, but did come to believe that the 'divine voice' I'd heard was nothing more than my brain screaming at me.
Since then, the trip has faded from my mind, but every time I look at coridicin, be it in a friend's hand, or in the store, I hear that voice again, and almost always puke instantly. As such, this dose is NOT recommended,and will probably prove fatal to someone not as lucky as I.
5.11 What is the "DXM Third Eye Camera"?
The "Third Eye Camera" (or "DXM Wacky-Cam" as one person called it) is a strange sense of vision that occurs sometimes after vision re-integrates in upper plateau trips. It is most prominent in Plateau Sigma experiences. There is a very pronounced strobing of vision without afterimages. As one moves one's eyes, the world seems to zoom back and forth (it seems that the inner model of the world isn't staying in synch with the outside; it may be that the brain has lost track of where the eyes are pointing). Vision is heavily dream-like and almost seems to persist with the eyes closed.
Somewhat more specific is one person's explanation that the "strobe light" seems to consist of regular pulses at roughly 8Hz, with small duty cycle (i.e., the "pulse" phase of the strobe is considerably shorter than the "non-pulse" phase). The frequency suggests theta rhythm, and there is research to back this up and potentially explain it (see Section 9.2.7). One person suggested that the strobe pulses seemed to be a negative image of the world, or perhaps an alternative view of it. It may be a strobing between an inner model of the visual space and sensory input. It might also be a flashing between the left eye's view and the right eye's view (another person suggested this). In any case, it seems to persist only until one goes to sleep, regardless of how much DXM is still hanging around in your body when you wake up.
5.12 Tussin Space, Tussin Consciousness
One of the more interesting phenomena that occur after one has gained experience with DXM is the development of a state-dependent memory. As the DXM experience starts, one finds onesself in comfortable, familiar territory, a space and consciousness unique to the DXM experience. Memories of former DXM trips can become easier to recall and more vivid. To many, this phenomenon is associated with a physical construct, a "Tussin Space," as more than one person has called it.
The exact nature of this space varies from person to person. Many find it to be a vast, open space, full of exotic and alien constructs, buildings and shapes. Some see crystalline towers and cloud-like lifeforms; others see the Tussin Space as a forest, desert, or other natural setting. Your Mileage May Vary. Many if not most don't really see it as a physical space at all.
Along with this space comes the unique but consistent changes in consciousness that lead to the state-dependent memory of the DXM experience. Called Tussin Consciousness by some, it becomes more and more familiar as one learns familiarity with DXM and becomes able to compensate for the memory inhibition.
5.13 What is the "Tussin Euphoria" and What Makes it Unique?
People do psychoactive drugs because in some sense they are pleasurable or beneficial. In some cases, such as cocaine and opiates, this takes the form of a "body high" or general euphoria resulting from stimulation of the brain's reward centers (the pathways of the ventral tegmental area, to be more specific). In other cases, like marijauna and LSD, the benefits are more emotional and intellectual. Many lab animals do not self-administer marijuana, and to my knowledge none self-administer LSD or related psychedelics.
DXM seems to lie somewhere in between; exactly where seems to depend on the individual. There is a definite DXM euphoria (called the "Tussin Euphoria" by the same people who refer to Tussin Space and Tussin Consciousness), but not everyone experiences it. Some in fact find DXM so profoundly disturbing that they never repeat the experience. A very few seem to find such incredible meaning and profundity to the DXM experience that it becomes psychologically addictive.
The Tussin Euphoria is totally unlike the euphoria from "body drugs" such as cocaine or heroin, and equally unlike the euphoria from MDMA (ecstasy). Instead, it is a sensation of being totally at peace with onesself, the universe, and other people. Ordinary cares and concerns seem to vanish as one enters a world where anything is possible, and the body becomes increasingly irrelevant. "Meat pleasures" such as food and sex are no longer relevant.
For those susceptible to it, the lure of the Tussin Euphoria can be significant. One person compared it to "The Nexus" from Star Trek: Generations; when in the Tussin Space, time has no meaning, and anything is possible. Basically it comes down to whether or not you enjoy being a discarnate entity, roaming around in a mental/spiritual world without physical interaction. Conversations are, of course, still a part of one's interactions, and many find great comfort and pleasure in group tripping. However, don't expect physical contact to be particularly profound; DXM is not a substitute for MDMA.
If you find yourself particularly susceptible to Tussin Euphoria, keep in mind that with frequent use of DXM it goes away and leaves one only with a sense of discomfort and dysphoria. In a very few individuals, this can continue into full-blown depression. Like all other drugs, you never get something for nothing.
5.14 What Can Happen with Long-term or Regular Use?
Long-term or regular use, especially in amounts above 6 mg/kg daily, tends to produce several undesirable effects, some of which may be dangerous. Although these are discussed in detail in Section 6.3, I will go over them briefly here.
The most significant risk of regular use of DXM is mental impairment (deterioration of language, motor skills, memory; loss of emotion; antisocial behaviour; violent ideation; etc.). Obviously there is mental impairment while intoxicated. However, some regular users have reported a temporary but long-term impairment (up to three months) after discontinuing regular use of DXM. The mechanism for this is unknown, but it has been reported with other dissociatives (355).
Permanent impairment is a more significant problem. There are two separate mechanisms for this: Olney's lesions (see Section 6.3.1) and hypertension-induced CVAs (stroke and cerebral hemorrhage). Olney's lesions are a particular type of dissociative-induced brain damage that occur in experimental animals at between 5 and 10 times anaesthetic doses, but may also occur with long-term use (though this is unproven). Hypertensive CVAs have been demonstrated with PCP (355) but not with DXM.
At least one study has shown permanent cognitive impairment from DXM (136), and I have received three additional reports of it (out of about 500). Generally speaking it doesn't seem to occur except with regular use of high dosages, and there may be underlying disorders (temporal lobe epilepsy, susceptibility to CVAs, etc) involved.
To make matters even worse, long-term sigma activity may cause permanent changes in neurons (101), although evidently this is predominantly a problem with other sigma ligands like haloperidol (it took 3 days for DXM to produce the changes haloperidol produced in a few hours).
A second risk concerns addiction (see Section 6.6). There doesn't seem to be much risk of physical addiction; while some have suggested that NMDA receptors upregulate with blockade (114), other studies dispute this. On the other hand, psychological addiction from dissociatives is well documented (194,202,203). Not everyone seems to be susceptible to this; genetic factors may be involved. For further information see Section 5.13 and Section 6.3.11).
One person related a story of DXM addiction which may give some perspective on the problem. The individual was roughly 60 kg, and took a dose of 480 mg, three or four times a day. The total dosage was thus 1440 mg to 1920 mg, i.e., 24 to 32 mg/kg. This individual took the dosage regularly to maintain a constant state of profound intoxication with a great deal of opiate-like effects; neglecting the dose led to withdrawal symptoms consistent with opiate withdrawal, and possibly also withdrawal from a depressant. The individual had no history of psychological problems. The individual developed severe depression, leading to a suicide attempt and several months in drug rehabilitation.
Exactly why some individuals seem to have drug dependence problems with DXM is unknown; it may be a function of chronic high-level use, or it may be a function of individual physiology. PLEASE NOTE that this user built up to this dose over a considerable time; a similar dose in a drug-naive individual could well be fatal.
Dissociative-induced depression is another concern with DXM, and has been documented (4,6,139-141,355). There may be biological factors involved. According to the data I have gathered, the incidence rate may be as low as 5% or as high as 40%, depending on how you look at things (I haven't done any formal studies yet, and in particular I have not used any established depression inventories, so my guesstimates must be taken with due skepticism). Paradoxically, some researchers suggest that dissociatives are actually antidepressants, but that, unlike those used in clinical practice, tolerance can build rapidly, leaving one with a rebound effect.
Other things to worry about are hypertensive crises, serotonin syndrome, damage to the kidneys, liver, and pancreas, heart arrhythmias, antisocial behaviour, psychotic breaks, muscle degeneration, etc. For the full story, see Section 6.3).
For better or for worse, most of the pleasurable effects of DXM tend to go away with regular use. Tolerance can build rapidly, leaving one only with a general sensation of being high and stupid.
A very few users report beneficial effects of chronic high-level use. The effects usually include some antidepressant activity (entirely reasonable given the possible significance of PCP2 receptors), stimulant activity, long-term motivational effect, and cognitive and creative enhancement (this has not been quantified and may be entirely subjective). It is arguable that chronic DXM use may actually be self-medication for depression in some people.
Overall, however, most people report that DXM loses its interesting characteristics when used regularly, leaving the more mundane and unpleasant aspects. One former user summed it up well by stating that "being addicted to DXM was like being addicted to heroin. Except not as fun." So please be careful and avoid regular use.
5.15 Why does DXM Affect Different People So Differently?
Several reasons. First off, there is a liver enzyme known as cytochrome P450-2D6 (also CYP2D6, or debrisoquine 4-hydroxylase), which metabolizes DXM. Some people lack this enzyme, and of those who have it, subtle genetic variations can result in different activity (10-18). Thus, while one person may metabolize DXM quickly, another may not (there are other pathways which are much slower). Certain drugs - such as fluoxetine (ProzacTM) can inhibit this enzyme (39). A partial list of P450-2D6 inhibiting drugs is given in Section 15.1.
Second, some of the effects of DXM are due to the DXM itself, and some are due to its metabolite dextrorphan (DXO), which is more similar to PCP and ketamine in its neuroreceptor activity (43). Some individuals may metabolize high doses of dextromethorphan to dextrorphan more quickly than others. Incidentally, my opinion - based on anecdotal evidence of recreational DXM use while on fluoxetine - is that both DXM and dextorphan are responsible for the psychoactive effects (yes, I changed my mind). There is evidence to show that DXM is definitely involved, and may be responsible for most of the lower plateau effects (32).
Third, NMDA receptors are intimately involved in many areas of the brain where a great deal of processing takes place, such as the hippocampus and the cerebellum. In contrast to the biogenic amine neurotransmitters (serotonin, dopamine, noradrenaline, histamine, and acetylcholine) which seem to play a modulatory role, excitatory amino acids and NMDA receptors are involved in the "nitty gritty" of brain processes. It is possible that, due to this extensive involvement, many different cortical and limbic circuits may be affected.
In fact, DXM affects at least four different binding sites (see Section 9.2), and each of these is subject to subtle variance from person to person (44).
A few people have suggested that temporal lobe epilepsy may greatly change the DXM experience (pers. comm.). If nothing else, it has been implicated in cognitive impairment from DXM use (136). Additionally, some of the more profound dissociative experiences (see Section 8.2.1) may be altered, and possibly amplified, by having an underlying susceptibility to seizures.
There are probably a gazillion other reasons why DXM has such a wide range of effects. Subtle differences in brain chemistry, notably in terms of sigma receptors, may also be involved. Psychological set, as well as setting, are undoubtedly also part of the problem.
5.16 How Does DXM Compare With Other Dissociatives?
Third and especially fourth plateau DXM experiences seem to resemble ketamine experiences, and based on reports of people who have done both, the similarity is considerable. This is not surprising, since both DXM and ketamine block NMDA receptors. Since v3.0 of the FAQ I have heard from PCP users who have tried DXM; all of them say that the two share little in common except at very high doses of DXM, and that even then the experiences are significantly different. PCP stands somewhat alone among dissociatives due to its unique neuropharmacology.
The lower DXM plateaus seem to show a number of differences from other dissociatives. This is most likely due to DXM's unique potency at the dopamine reuptake site (the PCP2 receptor) and the sigma receptor. DXM's ability to block dopamine reuptake is probably the biggest factor in its popularity at lower plateaus; neither ketamine nor PCP have substantial ability to do this.
When DXM is taken in divided doses, or when it is taken with an inhibitor of the P450-2D6 enzyme (e.g., fluoxetine), its sigma agonist activity becomes much stronger in comparison to its effect at the NMDA receptor. As expected, DXM taken under these conditions differs from other dissociatives, and is sometimes reported to induce schizophrenic-like thought processes and other unpleasant effects.