Adverse Reactions to Marihuana

Adverse acute reactions to marihuana are infrequent, but physicians will see more of them as use of the drug increases and reaches new areas of society. Several very distinct types of reactions occur. In persons without a history of mental disorder who have never taken hallucinogenic drugs, marihuana may cause simple depressive reactions, panic reactions (most common) and toxic psychoses. In persons who have previously taken hallucinogens, marihuana may also trigger recurrences of hallucinogenic effects and may occasionally precipitate delayed psychotic reactions. Finally, in ambulatory schizophrenics, marihuana can cause atypical reactions, frequently marked by derealization. Most of these reactions are self-limited and benign but can be worsened by improper medical management. A few require psychiatric and psychopharmacologic intervention.