Is cannabis effective and safe for managing mental health symptoms?

Cannabis use is common among patients with mental health conditions. Many people report using cannabis self-medication to manage conditions such as posttraumatic stress disorder (PTSD), depression and anxiety. As cannabis use becomes more prevalent, healthcare professionals will face more frequent questions about cannabis use during routine patient visits. A recent JAMA Internal Medicine review article outlines the importance for healthcare professionals to understand the lack of clear benefits of cannabis for mental health conditions and the potential for substantial adverse effects. The paper reviews what is known about the potential therapeutic benefits and risks of cannabis use across the following common mental health conditions: PTSD, anxiety, depression, bipolar disorder, psychosis and attention-deficit/hyperactivity disorder (ADHD). It also discusses cannabis use disorder, the effects of cannabis on cognition and interactions between cannabinoids and mental health medications.Evidence of benefitsThe review found that the potential benefits of cannabis for mental health conditions remain poorly studied. Low-certainty evidence indicates that Δ-9-tetrahydrocannabinol (THC)–predominant cannabis may not improve symptoms of PTSD. Furthermore, evidence is largely insufficient to characterize the effects of long-term THC-predominant cannabis use on anxiety, depression and ADHD. On the other hand, emerging low-certainty evidence suggests that cannabidiol (CBD) alone may reduce anxiety in patients with anxiety disorders. RisksThe review points out that THC-predominant cannabis use holds substantial risk for adverse mental health effects; counselling patients about these risks is crucial to promote safety. Risks include worsening mania symptoms and function in those with bipolar disorder and an increase in psychotic symptoms in those with psychotic spectrum disorders. Among people with past-year cannabis use, about three in 10 would be classified as having cannabis use disorder. About one-half of individuals with cannabis use disorder have moderate or severe disease with negative social, employment or other adverse outcomes. Regular use of high-THC-content products by adolescents and young adults is associated with several concerning risks, including an increased risk of psychosis (estimates range from a 2-fold to an 11-fold increased risk), a higher risk of cannabis use disorder, and a higher risk of self-harm in those with mood disorders. Cannabinoid interactions with mental health medicationsTHC and CBD are substrates, inhibitors and inducers of several metabolic enzymes, which may lead to significant drug–drug interactions with several commonly prescribed mental health medications. Examples include the following:Tricyclic antidepressants (e.g., amitriptyline, desipramine, imipramine). Cannabis inhibits CYP2C19 and 2D6, which increases antidepressant levels. Tricyclic antidepressants and THC both increase anticholinergic effects (e.g., tachycardia, delirium).Selective serotonin reuptake inhibitor antidepressants (citalopram, escitalopram, sertraline). Cannabis may increase their adverse effects (cough, diarrhea, dizziness, fatigue), presumably via CYP2C19 inhibition.Antiepileptics. Carbamazepine—cannabis inhibits metabolism and increases drug levels. Clobazam—CBD inhibits CYP2C19 and increases drug levels, which could increase somnolence and ataxia. Valproic acid—cannabis use elevates liver enzymes, with variable changes in drug levels.Benzodiazepines (clonazepam, diazepam, lorazepam). Both THC and CBD inhibit CYP3A4, while CBD inhibits UDP-glucuronosyltransferase 2B7. Benzodiazepine levels may be elevated, increasing the risk of sedation.Opioids. Buprenorphine—cannabis inhibits CYP3A4 and increases buprenorphine levels. Monitor for opioid withdrawal if a patient taking buprenorphine reduces their cannabis use.Drug interaction checkers specific to cannabis are publicly available (e.g., Penn State CANN-DIR Project). Healthcare professionals should check forinteractions with a patient’s medications as a part of counselling about cannabis use.Talking to patients about cannabis Healthcare professionals should engage patients with mental health conditions in discussions about cannabis due to its common use, influence on mental health symptoms, and being an important modifiable risk factor for mental health conditions in some populations. The review article outlines a potential framework that healthcare professionals can use to talk to patients about cannabis use and mental health. This is important as patients frequently obtain advice about cannabis from dispensary workers, who often lack medical training to engage in risk–benefit discussions.Ask about cannabis use in a routine and nonjudgmental manner (cannabis use screening tools are briefly discussed in the article).For patients wishing to use cannabis, encourage them to choose lower-potency (i.e., lower THC content) products and teach them to quantify and track THC dose.Discourage certain subgroups of patients from using cannabis due to increased risks of harms. These include adolescents and young adults (increased risk of developing psychotic spectrum disorders), those with bipolar or psychotic disorders (may worsen symptoms), pregnant individuals (may increase risk of preterm birth and low birth weight), and those at risk for substance use disorders (higher risk of developing cannabis use disorder).Educate patients about cannabis withdrawal syndrome if cannabis is used regularly for an extended period of time and then stopped. Withdrawal syndrome symptoms, such as insomnia, anxiety, restlessness and agitation, usually start within one to two days and peak two to six days after cannabis discontinuation. Slow tapering might minimize withdrawal symptoms.Advise patients to avoid smoking cannabis long term, because it may increase rates of bronchitis, risk of chronic lung disease, and risk of lung and other cancers.The review article also tabulates types of cannabis products (flower, hash, concentrates) and modes of use by common routes of consumption (inhaled—joint, spliff, blunt, pipe, bong/waterpipe, vape, dab; oral—capsule, edibles, tincture/oil; and topical—lotion, salve, balm, patch).SummaryOverall, current evidence is insufficient to support the use of cannabis for the treatment of mental health conditions, while evidence demonstrates substantial risks of adverse effects. Healthcare professionals have a vital role to play in educating and counselling patients about cannabis use to treat mental health symptoms or conditions and the potential for serious adverse effects.Reference:Kansagara D, Terry GE, Ayers CK, et al. Cannabis and mental health. A review. JAMA Intern Med 2026; published online March 9, 2026. (accessed March 16, 2026).

Is cannabis effective and safe for managing mental health symptoms?

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