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Cannabinoid

Medical cannabis: what the evidence shows

Legal on prescription in many countries; weak evidence for most mental-health uses. Includes THC, CBD and combinations. Legal status and evidence are two separate questions — this page is about evidence.

Not an approved treatment for any condition yet.

Last reviewed 23 October 2026Re-checked every month6 conditions with published evidence

Is medical cannabis legal where you live?See country-by-country rules on our Psychedelic Therapy Legality Map

Condition by condition

One card per condition, strongest evidence first. Hover or tap a label to see what it means; the numbers link to sources at the bottom of the page.

Chronic pain

Early research

Many trials, small benefits.

Pooling randomised trials of chronic pain, medical cannabis gave small improvements in pain, physical function and sleep — real, but modest.1

Compare every substance for chronic pain →

ADHD

Early research

One small trial missed its main goal.

In a 30-person randomised trial, a THC/CBD spray (Sativex) didn't significantly improve the main measure of attention and activity.2

Compare every substance for ADHD →

Anxiety disorders

Little or no evidence

Weak evidence at best.

The same review found very low-quality evidence for anxiety disorders; the only signal was low-quality evidence of small improvements in anxiety in people with other medical conditions.3

Compare every substance for anxiety disorders →

PTSD

Little or no evidence

Tested in a controlled trial — no better than placebo.

In a randomised crossover trial in 80 veterans, three types of smoked cannabis did no better than placebo on PTSD symptoms.4

Reviews rate the wider PTSD evidence as very low quality.3

Compare every substance for PTSD →

Safety and who it's not for

Daily use of high-potency cannabis is linked to higher rates of psychotic disorder across Europe.5

Keep reading

Medical Cannabis for Mental HealthHow THC and CBD work, which conditions have real evidence, dosing, risks and legal access.Read the article Medical Cannabis Is Legal In the UK, But Patients Still Face BarriersLegal in the UK since 2018, yet few get it on the NHS. Why most patients still pay privately.Read the article Does CBD Help With Sleep? What Science SaysWhat the mixed research says about CBD, doses and sleep.Read the article Research databaseNew studies, summarisedHundreds of papers on psychedelics and mental health, each with a plain-language summary and key facts.Browse the database

Sources

Numbered in the order they appear above. We only use peer-reviewed papers, official company announcements (for trial status and topline results), regulators and trial registries.

  1. Wang L et al. Medical cannabis or cannabinoids for chronic non-cancer and cancer related pain: a systematic review and meta-analysis of randomised clinical trials. BMJ. 2021Journal
  2. Cooper RE et al. Cannabinoids in attention-deficit/hyperactivity disorder: a randomised-controlled trial. Eur Neuropsychopharmacol. 2017Journal
  3. Black N et al. Cannabinoids for the treatment of mental disorders and symptoms of mental disorders: a systematic review and meta-analysis. Lancet Psychiatry. 2019Journal
  4. Bonn-Miller MO et al. The short-term impact of 3 smoked cannabis preparations versus placebo on PTSD symptoms: a randomized cross-over clinical trial. PLOS ONE. 2021Journal
  5. Di Forti M et al. The contribution of cannabis use to variation in the incidence of psychotic disorder across Europe (EU-GEI). Lancet Psychiatry. 2019Journal