Cannabis and mental health disorders: the short answer
The FDA has not approved cannabis or CBD to treat any mental health disorder. THC causes intoxication and can trigger panic, paranoia, and psychosis in some users. CBD does not cause intoxication. Studies on CBD for anxiety are small and short. Cannabis can also change blood levels of psychiatric drugs.
mental health effects of cannabis
THC and CBD act on different targets
THC binds CB1 receptors in the brain. CBD has low affinity for CB1. NIDA reports that THC content in seized US cannabis rose from about 4% in 1995 to about 15% in 2021. Higher THC means a higher dose per puff. Many online CBD oils test below their label claim, and some contain THC.
Psychosis and schizophrenia
A 2019 study in Lancet Psychiatry tracked 901 people with a first episode of psychosis and 1,237 controls at 11 sites in Europe. Daily use of cannabis with THC above 10% came with about three times the odds of a psychotic disorder compared with people who never used. Risk was higher for people who started before age 18. People with a family history of schizophrenia carry more risk from THC.
Mental Health Effects of Cannabis: A Guide to What the Evidence Shows
Anxiety
NIMH puts lifetime prevalence of any anxiety disorder in US adults at 31.1%. Most CBD anxiety trials enrolled fewer than 100 people and ran 4 to 12 weeks. One trial gave a single 300 mg CBD dose to 24 people with social anxiety disorder and reported lower anxiety during a public speaking test. That is one dose, one day, and a small group.
Cannabis Impact on Mental Health: What the Evidence Shows and How to Lower Your Risk
Depression
About 21 million US adults had at least one major depressive episode in 2022, per NIMH. No controlled trial shows that cannabis relieves depression. Cohort studies link heavy adolescent use to higher rates of depression and suicidal thoughts later.
Cannabis use disorder
CDC reports that about 3 in 10 people who use cannabis have cannabis use disorder. Risk rises with daily use and with first use before age 18. Withdrawal can include irritability, insomnia, and appetite loss.
Drug interactions and liver risk
CBD inhibits CYP3A4 and CYP2C19 enzymes. That can raise blood levels of clobazam, warfarin, and some antipsychotics. FDA labeling for Epidiolex, an approved CBD drug, lists liver injury as a risk at doses of 10 to 20 mg per kg per day. Psychiatric drugs with narrow margins need monitoring.
When to get help
Stop cannabis use and contact a clinician if you notice hallucinations, delusions, or a break from reality. In the US, call or text 988 for a mental health crisis. Bring a list of products, doses, and dates to the appointment. Clinicians cannot assess risk without that record.