SIR: Data that we have recently collected (1) support Dr. Fa - vazza's contention that a relationship exists between extent of marijuana use and susceptibility to "acid' flashbacks; We also point out, however, the applicability of a ditTerent inter - pretation, i.e., that acid flashbacks may lead to greater mari - juana use (rather than that increased marguana use leads to acid flashbacks). Dr. Favazza documents the idea that marguana induces LSD flashbacks by referring to an earlier case study he undertook with Dr. Edward Domino. In my opinion there is more evidence that the patient in this study shows a borderline or prepsychotic adjustment than is attested to by the authors. In particular, the MMPI data for their patient showed a fairly-severe level of maladjustment and I would be interested in seeing the total computerized MMPI report obtained. It is unfortunate that no MMPI was administered to this patient at an earlier date, which would have provided us with a baseline. As in 'the case mentioned in our most recent study ( 1), I wonder whether the prime variable is not ego functioning rather than marijuana per se. Dr. Anderson appears to assume that higher dosages of LSD would be more likely to induce flashbacks and that the same would hold for marijuana flashbacks. Concerning the former -, drug, however, Smart and Bateman (2) claimed that higher dos - ages do not produce more extreme psychotomimetic effects, al - though more frequent usage does induce flashbacks.