CBD for obsessive-compulsive disorder (OCD)

There is no good evidence that CBD helps obsessive-compulsive disorder. In the only placebo-controlled laboratory study of high-CBD cannabis, it did no better than placebo, and the one small trial of CBD on its own was too flawed to settle anything. Larger, properly controlled trials have not been done.

OCD is a mental health condition in which people have unwanted, distressing thoughts (obsessions) and feel driven to repeat actions or mental rituals (compulsions). Effective treatments include cognitive behavioural therapy and antidepressants called serotonin reuptake inhibitors.¹

What the research shows

The US laboratory study (Kayser 2020)

US researchers gave 14 adults with OCD, all of whom had used cannabis before, three types of cannabis to smoke in random order on separate days: high THC (7.0% THC), high CBD (10.4% CBD with 0.4% THC) and placebo. Twelve completed the study.²

• OCD symptoms and anxiety fell over time in all three sessions, including placebo.
• OCD symptoms did not differ between the high-CBD, high-THC and placebo cannabis.
• Anxiety was lower straight after placebo than after either the THC or the CBD cannabis.
• THC raised heart rate, blood pressure and intoxication.

The authors concluded that smoked cannabis, “whether containing primarily THC or CBD, has little acute impact on OCD symptoms”.² This was a single-dose study, so it cannot show what longer use does. The high-CBD cannabis also contained a small amount of THC.

The only placebo-controlled trial of CBD alone (Zahedi 2026)

An Iranian team randomly gave 30 people with OCD either 25 mg of CBD drops a day or placebo drops for eight weeks, alongside their usual medicines.³

• The authors reported that OCD scores fell in the CBD group over time, and described this as statistically significant between groups over time.
• The same abstract also says the OCD score “did not show any relationship between the two groups”.
• The groups were unbalanced: the average age was 32.5 in the CBD group and 40.6 in the placebo group, a statistically significant difference.³

With 15 people per group, unbalanced groups and conflicting statements about the main result, this trial cannot show that CBD works. The authors called for larger trials.³

The Brazilian open-label study

Researchers in Brazil added CBD to usual treatment for people whose OCD symptoms persisted. They gave 300 mg a day for 30 days, then 600 mg a day for those whose scores had not dropped by at least 25%. In an interim conference report, 33 people had been assessed, 19 had completed the study, 11 had dropped out and 3 were still taking part. Among those with results, average scores on the main OCD scale fell from 28.0 to 13.8 over eight weeks.⁴

This study had no placebo group, everyone knew they were taking CBD, and a third of participants did not finish. Without a placebo group, there is no way to know how much of the improvement would have happened anyway. See how we grade the evidence.

Pooled evidence

A 2025 meta-analysis of 21 placebo-controlled cannabinoid trials in anxiety-related conditions included only one in OCD. Across studies of pure or enriched CBD, the effect was not statistically significant.⁵ A 2026 review in The Lancet Psychiatry, covering all cannabinoids and mental disorders, found too little data on OCD to pool, and concluded that routine use of cannabinoids for mental disorders “is currently rarely justified”.⁶

What doses were tested

The studies used 25 mg a day,³ 300 to 600 mg a day,⁴ and a single smoked dose of high-CBD cannabis.² The Australian limit for pharmacist-only (Schedule 3) CBD is 150 mg a day.⁷ No dose has been shown to help OCD in a reliable trial. See CBD dosage: what trials used.

What Australian medical bodies say

• RANZCP. The Royal Australian and New Zealand College of Psychiatrists’ clinical memorandum, updated in March 2024, says there is insufficient evidence to support medicinal cannabis as a treatment for anxiety and other mental disorders, and raises concern about overprescribing.⁸
• RACGP. The Royal Australian College of General Practitioners says medicinal cannabis should only be considered after first-line, evidence-based treatments have been exhausted.⁹

See what Australian medical bodies say.

Risks to know about

• Antidepressants. Serotonin reuptake inhibitors are a standard OCD treatment.¹ CBD blocks liver enzymes that break down many drugs.¹⁰ In six young people in an Australian anxiety study who were also taking citalopram or escitalopram, citalopram blood levels rose after CBD was added.¹¹ See CBD drug interactions.
• Drowsiness. CBD adds to sedation from benzodiazepines, other sedatives and alcohol.¹⁰
• THC and anxiety. THC caused intoxication and raised heart rate and blood pressure in the OCD laboratory study.² Check whether any product contains THC. See CBD vs THC.
• Liver. At 350 to 400 mg a day, 5.6% of healthy adults had large liver enzyme rises within four weeks.¹² See CBD and the liver.

If you are considering it

• Talk to your GP or mental health professional about the established treatments for OCD, and whether you have had a full trial of them.
• If CBD is suggested, ask what trial evidence supports it for OCD. As of November 2026, there is no reliable trial.
• Bring a full list of your medicines, and ask how any new product would interact with them and how progress would be measured.

See talking to your GP about CBD.

This page is general information, not medical or legal advice. Laws and evidence change; we show the date we last checked the facts at the top of every page. Talk to your doctor or pharmacist before starting, stopping or changing any medicine.

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