Because marijuana is such an unimpressive pharmacological agent, it is not a very interesting drug to study in a laboratory. Pharmacologists cannot get a handle on it with their methods, and because they cannot see the reality of the non-material state of consciousness that users experience, they are forced to design experimental situations very far removed from the real world in order to get measurable effects. There are three conditions under which marijuana can be shown to impair general psychological performance in laboratory subjects. They are:

1. by giving it to people who have never had it before;
2. by giving people very high doses that they are not used to (or giving it orally to people used to smoking it); and
3. by giving people very hard things to do, especially things that they have never had a chance to practice while under the influence of the drug.

Under any of these three conditions, pharmacologists can demonstrate that marijuana impairs performance. And if we look at the work being done by NIMH-funded researchers, all of it fulfills one or more of these conditions. In addition, the tests being used by these scientists are designed to look for impairments of functions that have nothing to do with why marijuana users put themselves in an altered state of consciousness. People who get high on marijuana do not spontaneously try to do arithmetic problems or test their fine coordination. What pharmacologists cannot make sense of is that people who are high on marijuana cannot be shown, in objective terms, to be different from people who are not high. That is, if a marijuana user is allowed to smoke his usual doses and then to do things he has had a chance to practice while high, he does not appear to perform any differently from someone who is not high. Now, this pattern of users performing better than nonusers is a general phenomenon associated with all psychoactive drugs. For example, an alcoholic will vastly outperform a nondrinker on any test if the two are equally intoxicated; he has learned to compensate for the effects of the drug on his nervous system. But compensation can proceed only so far until it runs up against a ceiling imposed by the pharmacological action of the drug on lower brain centers. Again, since marijuana has no clinically significant action on lower brain centers, compensation can reach 100 percent with practice.

These considerations mean that there are no answers to questions like, What does marijuana do to driving ability? The only possible answer is, It depends. It depends on the person - whether he is a marijuana user, whether he has practiced driving while under the influence of marijuana. In speaking to legislative and medical groups, I have stated a personal reaction to this question in the form of the decision I would make if I were given the choice of riding with one of the following four drivers:

1. a person who had never smoked marijuana before and just had;
2. a marijuana smoker who had never driven while high and was just about to;
3. a high marijuana smoker who had practiced driving while high; and
4. a person with any amount of alcohol in him.

I would unhesitatingly take driver number three as the best possible risk. One may wonder how many drivers of types one and two are on our highways. Probably many. But there is some consolation in the fact that persons learning to do things under the influence of marijuana almost always are anxious about their performance and therefore tend to err on the side of overcaution.

The tendency for novice users of marijuana to imagine that their psychological functioning is disrupted to a much greater degree than it actually is, is most noticeable in conection with subtle changes in speech. People who are high on marijuana seem to have to do slightly more work that usual to remember moment to moment the logical thread of what they are saying. This change manifests itself in two ways: as a tendency to forget what one started out to say, especially following an interruption, and a tendency to go off on irrelevant tangents. Zinberg, Nelson and I were able to pick up these changes in tape recordings of our Boston subjects, but I must emphasize the adjective subtle in describing them. Someone not specially trained to listen for these changes would not hear them. Interestingly enough, however, marijuana users themselves often imagine they are not making sense and become anxious about other people guessing that they are high. Some users experience this subjective anxiety about speech most intensely when they are talking on the telephone. Here is a quote from such a user (a twenty-four-year-old male medical student), which Zinberg and I included in a paper published in Nature in 1969:

I've learned to do a lot of things when I'm stoned and seem to function well in all spheres of activity. I can also "turn off" a high when that seems necessary. The one problem I have, however, is talking to straight people when I don't want them to know I'm stoned. It's really scary because you constantly imagine you're talking nonsense and that the other person is going to realize you're high. That's never happened, though, so I conclude that I don't sound as crazy to others as I do to myself. It's worst on the telephone. Someone will call up and be talking to me, and when he stops I'll have no idea what he just said. Then I don't know what I'm supposed to answer and I have to stall until I get a clue as to what's expected of me. Again, even though this is very disconcerting, the other party never seems to notice that anything's wrong unless he's a heavy grass smoker, too, and then it doesn't matter.1

Probably, the subtle difficulties in speech that high users pay great attention to are themselves manifestations of a change in a more general psychological function called immediate memory. It seems valid to distinguish three kinds of memory in man. The first has been termed immediate and seems to cover events of the past few seconds only. It is as if all information coming into the brain is held in some location for a very short time before a decision is made about where to store it. If it is to be filed in an accessible place, it passes to a second storage location called recent memory, where it may remain for days or, perhaps, weeks; otherwise it is salted away out of reach of ordinary consciousness. Eventually, if it is to be kept in an accessible place for a longer time, it moves to a third long-term storage location, which is the permanent memory file. Each of these locations has active connections to ordinary consciousness so that memories may be quickly retrieved from all of them in our normal waking state.

In senile dementia, the classic psychological change is loss of recent memory with sparing of immediate and long-term memory. A senile patient can remember a string of numbers read to him long enough to recite them back and can go into autobiographical detail about his childhood. He cannot remember the date or the events of the previous day. By contrast, in certain forms of post-traumatic amnesia, immediate and recent memory are spared, but information filed prior to the trauma cannot be retrieved from the long-term memory storage. A person high on marijuana seems to have difficulty remembering what happened in the past few seconds, and the subtle speech changes reflect this difficulty. Furthermore, it looks as if a significant disturbance of immediate memory retrieval has few noticable consequences in terms of behavior, although it may cause great anxiety in the mind of the person experiencing it.

This last observation raises an interesting question. Is the problem disturbance of immediate memory or anxiety about this change? Most people who have read the hypothesis Zinberg and I first presented in Nature have drawn the conclusion that marijuana interferes with immediate memory. In fact, the director of the National Institute of Mental Health, in testimony before Congress in 1970, used our results to support the statement that "more recent studies . . . in which researchers have learned some troublesome facts . . . make it impossible to give marijuana a clean bill of health."2 I would once have gone along with this kind of reasoning, but the more I have thought about the matter, the more it has become clear to me that it is not useful to think of marijuana as interfering with one's awareness of the immediate past.

For one thing, disturbance of immediate memory seems to be a common feature of all altered states of consciousness in which attention is focused on the present. It can be noticed in hypnotic and other trances, meditation, mystic ecstasies, and highs associated with all drugs. Therefore, to call marijuana the cause of the phenomenon is probably unwise. In addition, the phrase disturbance of immediate memory bristles with negativity. Is it a negative description of a condition that might just as well be looked at positively? I believe so. In fact, the ability to live entirely in the present, without paying attention to the immediate past or future, is precisely the goal of meditation and the exact aim of many religious disciplines. The rationale behind living in the present is stated in ancient Hindu writing and forms a prominent theme of Buddhist and Christian philosophy as well: to the extent that consciousness is diverted into the past and future -- both of which are unreal -- to that extent is it unavailable for use in the real here and now. Consequently, monastic systems of all faiths have used devices like gongs and bells to focus the consciousness of the novice on the immediate reality of the present, and contemporary instructional materials on mental and spiritual development stress the same theme. Here are a few examples:

1. From A Practical Guide to Yoga by James Hewitt
   
   When the mind is stilled by Raja Yoga, time--that is to say, psychological time--ceases to exist. For time is relative. It only exists when one thing is taken in relation to another. If I go on a train journey my leaving the train at my destination, taken in relation to my getting in, shows a passage of time. Similarly, if I think of "fruit," and in a split second follow with another thought "apples," time has passed, and I am aware of its passing. But if the mind takes one thought and holds it, one-pointed and still, time is erased; it ceases--psychologically--to exist.
   
   In the hurly-burly of civilized living we rarely find time, or even give a thought to living in the NOW. We spend our NOW thinking of the past or dreaming of the future. Raja Yoga enables us to be still and experience eternity, as defined by Boethius: "to hold and possess the whole fullness of life in one moment, here and now, past and present to come."3



2. The following excerpt is from C.S. Lewis' Screwtape Letters--a witty and practical statement of orthodox Christian theology cast in the form of letters from a senior devil, Screwtape, to a junior devil, Wormwood, who is trying to capture the soul of an earthly "patient":
   
   MY DEAR WORMWOOD,
   
   I had noticed, of course, that the humans were having a lull in their European war [World War II]--what they naively call "The War!"--and am not surprised that there is a corresponding lull in the patient's anxieties. Do we want to encourage this or to keep him worried? Tortured fear and stupid confidence are both desirable states of mind. Our choice between them raised important questions.
   
   The humans live in time, but our Enemy destines them to eternity. He therefore, I believe, wants them to attend chiefly to two things, to eternity itself and to that point of time which they call the Present. For the Present is the point at which time touches eternity. Of the present moment, and of it only, humans have an experience analogous to the experience which our Enemy has of reality as a whole; in it alone freedom and actuality are offered them. He would therefore have them continually concerned either with eternity (which means being concerned with Him) or with the Present--either meditating on their eternal union with, or separation from, Himself, or else obeying the present voice of conscience, bearing the present cross, receiving the present grace, giving thanks for the present pleasure. Our business is to get them away from the eternal and from the Present.4



3. From Concentration and Meditation by Christmas Humphreys:
   
   As the sequence of day and night, so is the alternation of work and rest, and it is in the minutes of comparative repose that the difference appears between the trained and the untrained student of mind-development. The beginner allows his energy to drain away in idle conversation or mental rambling, in vague revision of past experiences or anxiety of events as yet unborn, or in a thousand other wasteful ways for which, were he spending gold instead of mental energy, he would be hailed as a reckless spend-thrift to be avoided by all prudent men.5



4. The following summary of J. Krishnamurti's philosophy of time is from Metaphysical Approach to Reality by Ganga Sahai, Mr. Krishnamurti's recent books are widely available in the West.
   
   There is a state of being which Krishnamurti calls the timeless. It comes with the realization that the only real moment is the moment of the Now, the eternal present; the past and future taken as "no-more" and "not-yet" are illusions.
   
   The center, the observer, is memory. The center is always in the past. Therefore, the center is not a living thing. It is a memory of what has been. When there is complete attention, there us no observer....
   
   Life is broken up and this breaking of life, caused by the center "me," is time. If we look at the whole of existence without the center "me" there is no time.
   
   The new dimension is the silent mind. It is always in the present, always in the Now. It is the timeless mind that really exists.6

Thus the pharmacological way of thinking leads to the formulation of a hypothesis built upon an incorrect causal attribution and a negatively biased description of a phenomenon assigned great value in other ways of thinking. The pharmacologist says marijuana interferes with immediate memory, and by using tests in which one is penalized for not paying full attention to the past, the pharmacologist can produce evidence to document his hypothesis. The National Institute of Mental Health is supporting this kind of research with money appropriated by Congress. It is not funding research designed to look for the positive advantages of having one's full awareness focused on the present.

In a similar way, all other psychological effects of marijuana turn out to be common features of altered states of consciousness unassociated with drugs, and whenever pharmacologist describes them in negative ways, it is possible to look at them positively from the point of conscious experience. The perceptual changes reported by marijuana users are another example. Here again is an apparent paradox since all testing to date has failed to show any objective changes in sensory function during acute marijuana intoxication. If pharmacologists paid closer attention to what users say, they would find their way out of this paradox. There is no indication from persons high on marijuana that their sense organs are working differently from usual. Rather, the change seems to be in what they do with incoming sensory information. For instance, many users claim that listening to music is more interesting and pleasurable when they are high. They do not claim that they hear tones of lower volume or that they can better discriminate between pitches of tones. Yet all of the testing of auditory function under marijuana has been aimed at the ear--at auditory thresholds, pitch discrimination, and the like.

In 1969, when I still thought as a pharmacologist in my professional life, I wrote the following paragraph in an article, "Cannabis," published in England in Science Journal:

It would make more sense to look for effects not on the ear but rather on that part of the brain that processes auditory information. Cannabis seems to affect the secondary perception of sensory information, not the primary reception of it. Unfortunately, it is considerably harder to study secondary perception because the neural organization underlying it is less accessible to direct experimentation and much less well understood. A working hypothesis is that incoming sensory information (such as auditory signals representing music) normally follows conditioned pathways through the secondary perception network in order to get to consciousness. Under Cannabis, which might interfere with this normal processing, information may take novel routes to consciousness and thus be perceived in novel ways. Such a model would explain why users often say that under Cannabis they see things for the first time "as they really are," or why they dwell on aspects of complex visual or auditory stimuli they would ordinarily ignore.7

I now realize that altered secondary perception of sensory information is intrinsic to all altered states of consciousness, whether triggered by drugs or not. Therefore, it no longer seems profitable to me to try to understand how marijuana "causes" the effect. In addition, I no longer subscribe to the negative hypothesis that marijuana interferes with normal processing of perceptual data. Rather, I observe that in altered states of consciousness, one frequently gains the ability to interpret his perceptions in new ways and that this ability seems to be the key to freedom from bondage to the senses. For example, hypnotic anesthesia is nothing more than another way of perceiving pain. The patient, fully aware but in a state of focused consciousness, learns the "trick" of separating the pain itself from his reaction to it. He is thus free to perceive the pain in a novel way - something going on "out there" but not hurting. (One hypnotist I know produces this state with the suggestion that "the hurt is going out of the pain.")

Furthermore, the ability to produce anesthesia at will (a power frequently demonstrated by adepts at yoga) may be no more than a trifling use of this freedom to experience sensations in other ways. Once one learns the process, he may become aware of many more useful things to do with it than ignore pain. For example, the conscious experience of unity behind the diversity of phenomena - said by sages and mystics of all centuries to be the most blissful and uplifting of human experiences - may require nothing more than a moment's freedom to stand back from the inrush of sensory information and look at it in a different way from usual. If all the so-called psychological effects of marijuana are really not attributable to marijuana, and if the physical effects that are attributable to it are so unimpressive, what, then, is marijuana? To my mind, the best term for marijuana is active placebo - that is, a substance whose apparent effects on the mind are actually placebo effects in response to minimal physiological action. Pharmacologists sometimes use active placebos (in contrast to inactive placebos like sugar pills) in drug testing; for example, nicotinic acid, which causes warmth and flushing, has been compared with hallucinogens in some laboratory experiments. But pharmacologists do not understand that all psychoactive drugs are really active placebos since the psychic effects arise from consciousness, elicited by set and setting, in response to physiological cues.

Thus, for most marijuana users, the occasion of smoking a joint becomes an opportunity or excuse for experiencing a mode of consciousness that is available to everyone all the time, even though many people do not know how to get high without using a drug. Not surprisingly, regular marijuana users often find themselves becoming high spontaneously. (The pharmacologist invokes "residual concentrations of Cannabis constituents in the body" to explain this observation.) The user who correctly interprets the significance of his spontaneous highs takes the first step away from dependence on the drug to achieve the desired state of consciousness and the first step toward freer use of his own nervous system. All drugs that seem to give highs behave this way; all are active placebos. But the less physiological noise, the easier it is for a user to understand the true nature of drugs and their highly indirect relationship to states of consciousness. Alcohol users are less likely to find themselves spontaneously high because they have come to think that "high" includes all the pharmacological noise of alcohol. At the same time, marijuana, while providing a better opportunity to make the jump to drugless highs, is more insidious as a creator of illusion, for it enables the user to pretend that he is not really dependent on it at the same time that it reinforces the notion that highs come in joints, an irony that recalls another unsettling comment of C. S. Lewis' Screwtape: "Nowhere do we tempt so successfully as on the very steps of the altar."8