More than a third of people who experienced psychosis with cannabis use later transitioned to schizophrenia, according to a systematic review and meta-analysis published online in Schizophrenia Bulletin.
Similarly, schizophrenia transition risk among people who experienced psychosis from hallucinogen or amphetamine use was also considerable.
“These findings have important implications for mental health care and services. Substance-induced psychoses are common reasons for seeking mental health care,” a Psychiatric News Alert quoted from the study. “Yet despite this, people with substance-induced psychoses are often excluded from early psychosis services or assertive mental health care due to a perception that these are benign or self-limiting conditions.”
The meta-analysis spanned 50 studies which provided 79 estimates of transition to schizophrenia among 40,783 people with substance-induced, brief, or atypical psychoses. Some 25 of the studies, which included 34,244 people, had substance-specific estimates.
Overall, 25% of people who experienced substance-induced psychosis transitioned to schizophrenia, researchers reported. The rate of transition for people who transitioned to schizophrenia after brief, atypical, or not-otherwise-specified psychoses was 36%.
The highest rates of transition to schizophrenia were associated with cannabis-induced psychosis (34%), hallucinogen-induced psychosis (26%), and amphetamine-induced psychosis (22%), according to the study. Transition rates were lower when drug-induced psychosis was associated with opioids (12%), alcohol (10%), and sedatives (9%).
“Substance-induced psychoses associated with cannabis, hallucinogens, and amphetamines have a substantial risk of transition to schizophrenia,” researchers wrote, “and should be a focus for assertive psychiatric intervention.”
Murrie B, Lappin J, Large M, Sara G. Transition of substance-induced, brief, and atypical psychoses to schizophrenia: a systematic review and meta-analysis. Schizophrenia Bulletin. 2019 October 16;[Epub ahead of print].