Psychosis and Mania Vulnerability

Urgent first

Hallucinations, severe confusion, a sense of losing touch with reality, or thoughts of self-harm after cannabis need urgent care. In the US, NIDA says to call 911 or go to an emergency department, and to call or text 988 to reach the 988 Suicide & Crisis Lifeline. [1] See when to seek urgent help after cannabis.

How to read this page

This page is education, not diagnosis or medical advice. Most findings come from observational studies, which show that two things occur together (association) and cannot prove that one caused the other. Evidence labels: evidence of harm (association seen in studies), mixed, insufficient evidence. Nobody should stop or change a psychiatric medicine because of this page; talk with the prescriber.

Psychosis

What it is. The US National Institute of Mental Health describes people with psychosis as typically experiencing delusions (false beliefs) and hallucinations (seeing or hearing things that others do not). [2]

Temporary episodes. NIDA says cannabis intoxication can induce a temporary psychotic episode in some people, especially at high doses, and that such an episode may be linked with developing a psychotic disorder later. [1] A 2020 meta-analysis of 50 studies found that about 34% of people with cannabis-induced psychosis went on to a schizophrenia diagnosis (6 studies, 95% confidence interval 25% to 46%), the highest rate among the substances compared. [3]

Dose and frequency. A 2023 meta-analysis of 10 studies (7,390 participants) found the risk of psychosis rose with how often people used cannabis. It was significant for weekly use (risk ratio 1.35) and daily use (1.76), and not significant for yearly (1.01) or monthly (1.10) use. [4] A European case-control study of first-episode psychosis (901 patients, 1,237 controls) found daily use was linked to 3.2 times the odds of a psychotic disorder, and nearly 5 times for daily use of high-potency cannabis, defined in that study as 10% THC or more. [5] That percentage is a study cutoff based on expected THC in local cannabis, not a measurement of any product.

Overview of reviews. A review of 26 meta-analyses and systematic reviews found that psychotic illness arises more frequently in cannabis users than non-users, with a dose-dependent risk and earlier onset, and that cannabis use is associated with more relapses, hospitalizations and worse positive symptoms in people who already have psychosis. [6] NIDA says the link between heavy use and schizophrenia appears especially strong in young males. [1]

What is not settled. NIDA notes that genes, trauma and stress also influence both mental health and drug use, and says long-term studies are needed to learn whether, to what extent and for whom cannabis may cause or contribute to poor mental health outcomes. [1] Label: evidence of harm (association) for frequent use; cause in any one person cannot be shown.

The 2023 BMJ umbrella review of 101 meta-analyses rated as high certainty that in the general population cannabis worsened positive psychotic symptoms and total psychiatric symptoms, and it supports avoiding cannabis in people prone to or with mental health disorders. [7]

Mania and bipolar disorder

The National Institute of Mental Health describes bipolar disorder as causing clear shifts in mood, energy and activity, with periods of extremely "up," elated, irritable or energized behavior known as manic episodes. [8] A systematic review of six prospective studies (2,391 people with manic symptoms) found cannabis use associated with worse manic symptoms in people with bipolar disorder, and a meta-analysis of two studies suggested about three times the odds of new manic symptoms (odds ratio 2.97). The authors called their conclusions tentative and preliminary because few, variable-quality studies exist. [9] Label: insufficient to mixed evidence; a signal worth taking seriously.

Which products?

The studies above mostly describe cannabis containing THC. Whether CBD-only products affect psychosis risk was not established in the sources read for this page, so no claim is made. Studies of an approved CBD medicine are separate; see approved cannabinoid medicines.

Adolescents

Younger people are a focus of concern. NIDA reports that cannabis use at a young age has been linked to the likelihood of developing psychosis. [1] See cannabis and adolescents and adverse effects.

If you or a family member has a history

People with a personal or family history of psychosis or bipolar disorder, or who are on psychiatric medicines, should talk to a clinician before considering any cannabis or cannabinoid product. This page cannot say who is safe.