Psychiatric symptoms in cannabis users.

Cannabis intoxication produces experiences that resemble psychiatric symptoms, but these differ from adverse reactions, the most common being acute anxiety. Acute psychotic episodes after cannabis use are infrequent and present either as confusional states or episodes in clear consciousness; neither has specific features that justify a distinct 'cannabis psychosis' diagnosis. Evidence that cannabis causes chronic psychotic or affective disorders is not convincing, though it may alter the course of an existing illness. Further controlled studies are needed to clarify any causal role.

Study at a glance

Abstract

The usual phenomena of cannabis intoxication include experiences which in a non-intoxicated state would be considered as psychiatric symptoms. These can be distinguished from adverse reactions to cannabis, the commonest of which is an acute anxiety state. Acute psychotic episodes can also follow ingestion of the drug but are infrequent. These can be classified as acute confusional states and episodes occurring in clear consciousness. Neither presentation consistently shows enough specific features to warrant the diagnosis of 'cannabis psychosis' as a distinct clinical entity. The evidence that cannabis has a causative role in chronic psychotic or affective disorders is not convincing, although the drug may modify the course of an already established illness. Further controlled studies would be required to clarify the aetiological significance of the drug in these conditions.