A questionnaire study of 42 randomly selected young men who used marijuana revealed that about 90 percent had experienced minor changes in perception (seeing colors or objects as more intense); about half had experienced major perceptual changes (hallucinating colors or designs); and about 40 percent had experienced hallucinogenic ideation. The authors conclude that marijuana, as used by the population studied, is a hallucinogen. They caution, however, that this is not evidence that the drug is either harmful or harmless.Abstract Teaser