Cannabis and psychotic illness.
The British journal of psychiatry : the journal of mental science November 1, 1992 DOI: 10.1192/bjp.161.5.648 (opens in new tab)
Study at a glance
AI-extracted from the abstract| Characteristics | Observational cohort Peer reviewed |
|---|---|
| Population | In-patients with psychotic symptoms and cannabis-positive urine analysis, compared with psychotic patients with drug-free urine analysis |
| Duration | 6-month follow-up |
| Topics | Cannabis |
| Key findings | Cannabis-positive psychotic patients differed from drug-free patients on only five PSE items at one week, one item at one month, and none at six months, indicating no chronic cannabis-induced psychosis was found. |
Abstract
In-patients with psychotic symptoms and cannabis-positive urine analysis were assessed by PSE within one week of admission and again at one and six months. Concurrently admitted psychotic patients with drug-free urine analysis were controls. At one week the two groups differed significantly on only five PSE items: changed perception, thought insertion, non-verbal auditory hallucinations, delusions of control, and delusions of grandiose ability. One item (delayed sleep) differed at one month, and none at six months. The symptom cluster at one week is consistent with acute cannabis intoxication. Subjects and controls were mostly single, poorly educated, unemployed people with histories of psychotic disorders, and given major tranquillisers on admission. Compared with controls, subjects were younger, less likely to have psychiatric histories, more often male, Afro-Caribbeans with a history of convictions and compulsory admissions. The commonest diagnosis was schizophrenia. Use of the label 'cannabis-induced psychosis' may obscure a diagnosis of paranoid schizophrenia. A short-lived psychotic episode does occur in clear consciousness after cannabis intoxication, but chronic cannabis-induced psychosis was not found.