The National Commission on Marihuana and Drug Abuse

Marihuana - A Signal of Misunderstanding.

Chapter II

marihuana use and its effects

Mental Functioning

The incidence of psychiatric hospitalizations for acute psychoses and of use of drugs other than alcohol is not significantly higher than among the non-using population. The existence of a specific longlasting, cannabis-related psychosis is poorly defined. If heavy cannabis use produces a, specific psychosis, it must be quite rare or else exceedingly difficult to distinguish from other acute or chronic psychoses.

Recent studies suggest that the occurrence of any form of psychosis in heavy cannabis users is no higher than in the general population. Although such use is often quite, prevalent in hospitalized mental patients, the drug could only be considered a. causal factor in a, few cases. Most of these were, short-term reactions or toxic overdoses. In addition, a concurrent use of alcohol often played a role in the, episode causing hospitalization.

These findings are somewhat surprising in view of the widespread belief that cannabis attracts the mentally unstable, vulnerable individual. Experience in the United States has not involved a level of heavy marihuana, use comparable to these foreign countries. Consequently, such long-lasting psychic disturbances possibly caused by heavy cannabis use have not been observed in this country.