Does Cannabis Raise the Risk of Bipolar Disorder?

A new meta-analysis of 19 studies found that people who used cannabis were about two and a half times as likely to develop bipolar disorder later, and about twice as likely to develop manic or hypomanic symptoms, compared with people who did not [1]. This shows a link, not proof of cause. If you use cannabis, or ganja, and notice unusually high energy, little need for sleep or racing thoughts, speak to a doctor.

Does Cannabis Raise the Risk of Bipolar Disorder at a glance

• Study: a 2026 systematic review and meta-analysis of 19 long-term observational studies, covering nearly 7 million people [1].
• Bipolar disorder: risk ratio 2.46 for cannabis users vs non-users (95% CI 1.57 to 3.84) [1].
• Manic or hypomanic symptoms: risk ratio 2.11 (95% CI 1.07 to 4.18) [1].
• Limits: these are observational studies, so they cannot prove that cannabis is the cause [1].
• Cannabinoid medicines have not been shown to treat these conditions reliably, and the evidence is very low certainty [2].

What did the new study find?

Researchers searched for studies that followed people over time, starting with people who had never had bipolar disorder. They compared those who used cannabis with those who did not, then counted who later developed bipolar disorder or manic symptoms. They found 19 studies with 6,960,517 participants in all. The average age was about 24 [1].

Cannabis use was linked to a risk ratio of 2.46 for later bipolar disorder (from 8 studies) and 2.11 for manic or hypomanic symptoms (from 6 studies). Study quality scores were good to high [1]. The authors suggest that doctors should routinely ask about cannabis and support efforts to delay first use and reduce use [1].

Does that mean cannabis causes bipolar disorder?

Not necessarily. A risk ratio of 2.46 means that cannabis users developed bipolar disorder at roughly two and a half times the rate of non-users in these studies. It does not tell us why.

Two other explanations are possible. First, people who are already developing bipolar disorder, who may feel restless or low long before diagnosis, might be more likely to use cannabis to cope. Second, genes, family history, stress or other substance use could raise the risk of both. The authors report that the meta-analysis was based on unadjusted risk ratios, and that there were sources of variation between studies [1]. So the figure should be read as a warning sign, not a precise measure of harm.

Why does this matter for young people in India?

Cannabis reaches young people in India as ganja, charas and bhang, among other forms. The people in this review were young, with an average age of about 24, so the findings are most relevant to teenagers and young adults [1].

If someone in your family has bipolar disorder, it is sensible to talk to a doctor before using cannabis at all. If you or a family member already has a bipolar diagnosis, a related review of 48 studies found that cannabis use disorder is often linked with more manic episodes, rapid cycling, psychosis and an earlier start of illness, though findings on depression and treatment response were mixed [3].

Can cannabis or CBD treat mental illness?

Some people believe cannabis calms the mind. The evidence is thin. A 2026 meta-analysis of 82 experimental studies found that cannabinoids lowered anxiety scores in some trials, with a very small effect on depression, ADHD or psychosis. In one trial, cannabinoids actually worsened the severity of cannabis use disorder. The authors rated the certainty as mostly very low and said it was not enough to support cannabinoids as first-line treatment [2].

What the three reviews tell us about cannabis and mental health [1,2,3].

What are the warning signs, and what should you do?

Mania and hypomania can feel good at first, which is why they are missed. Watch for several days of unusually high energy or irritability, needing much less sleep without feeling tired, racing thoughts, talking faster than usual, taking risks with money or driving, or big plans that are out of character.

• Do not stop prescribed mood medicines on your own.
• If you have bipolar disorder or a close relative with it, discuss cannabis use with your doctor.
• If you are using daily and find it hard to cut down, ask for help. Dependence is a medical condition, not a character flaw.
• If you have thoughts of suicide, call Tele-MANAS on 14416 (free, 24 hours a day) or 112 in an emergency.

Getting help in Delhi

Brain Bridge Clinic in Safdarjung Enclave, New Delhi, offers psychiatric assessment for mood disorders and de-addiction support, including care for people who have both a mood disorder and a substance use problem. A first visit usually includes a detailed history of your mood, sleep, family background and substance use, without judgement, and a plan that treats the mood condition and the substance use together. Families can be involved if you wish. If you would like an assessment, you can book through the website or by phone.

Related pages: Bipolar Disorder, De Addiction, De Addiction Rehab Programs, Bipolar OCD.

Frequently asked questions

Does smoking ganja cause bipolar disorder?

Studies show a link, with cannabis users having higher rates of later bipolar disorder, but they cannot prove cannabis is the cause [1].

Can occasional use trigger mania?

The meta-analysis grouped many patterns of use, so it cannot tell you a safe amount. Talk to a doctor if you have bipolar disorder or a strong family history of it.

Is CBD safe for bipolar disorder?

There is no strong evidence that cannabinoids treat bipolar disorder. A large review found very low certainty evidence across mental disorders [2]. Discuss any product with your psychiatrist first.

What if I already use cannabis and have bipolar disorder?

Talk to your doctor before making changes, especially to prescribed medicines. Cannabis use disorder in bipolar disorder has been linked with more manic episodes and rapid cycling [3], so a plan with your doctor helps.

Can bipolar disorder be treated?

Yes. It is a long-term condition that is managed with medicines, psychological support and a steady routine. A psychiatrist can explain the options for you.

References

1. Sanjuan-Ortiz C, Querol P, Aymerich C, et al. Cannabis use and subsequent onset of manic symptoms and bipolar disorder: A systematic review and meta-analysis. Journal of affective disorders. 2027;416:122588. doi:10.1016/j.jad.2026.122588. PMID 42838231.
2. Bharat C, Huang X, Campbell G, et al. Cannabis and cannabinoids for the treatment of mental and substance use disorders and symptoms: A systematic review and meta-analysis of experimental and observational studies. Psychiatry research. 2026;365:117380. doi:10.1016/j.psychres.2026.117380. PMID 42617303.
3. Garvie S, Sorkhou M, George TP. Clinical Phenomenology of Bipolar Disorder With Substance Use Disorders: A Systematic Review. Bipolar disorders. 2026;28(5):e70132. doi:10.1111/bdi.70132. PMID 42286971.