Cochrane review of 537 people: evidence medical cannabis helps insomnia remains limited

On 13 October 2026, Cochrane published a systematic review of medical cannabis for insomnia. Its conclusion: reliable evidence that medical cannabis improves insomnia remains limited.

The review appears in the Cochrane Database of Systematic Reviews, issue 10, 2026 (DOI: 10.1002/14651858.CD016216.pub2). The first author is Lucia B. Varela and the senior author is Luis I. Garegnani.

9 studies, 537 people: little or no improvement

The team included 9 studies involving 537 adults aged 18 to 76. Eight compared medical cannabis with placebo, and the remaining one compared it with the antidepressant amitriptyline.

Compared with placebo, medical cannabis brought little or no clinically meaningful improvement in sleep quality and satisfaction, total sleep time or daytime function.

Quality of life was the only outcome that appeared to improve somewhat, but the certainty of evidence was very low. The pooled results ranged from a slight worsening to a large improvement, too wide a range to support a judgement.

On side effects, people taking medical cannabis were significantly more likely to report mild adverse effects such as dry mouth and dizziness. The authors noted, however, that this finding rested on only a few studies.

Why the evidence is weak

The review rated the overall certainty of evidence as "very low to low". The problems the authors identified include:

• Risk of bias, inconsistent results and small samples.
• The cannabis products varied widely between studies, making direct comparison difficult.
• The longest follow-up was only 12 weeks, so long-term effects remain unknown.
• Women made up 72.66% of participants, who also skewed younger, so results may not apply to men, older people or those with other conditions.

Insufficient evidence is not proof of no effect

Varela stressed that the findings do not mean medical cannabis is ineffective. Garegnani said the existing evidence is too weak and uncertain to draw firm conclusions. The authors called for larger, more rigorous clinical trials.

Until new research arrives, get the sleep basics right

Rather than pinning hopes on a product with unclear evidence, it may help to review daily habits. The sleep habits listed on the US Centers for Disease Control and Prevention (CDC) website include:

• Keep a consistent schedule.
• Keep the bedroom dark, quiet and cool.
• Turn off screens about half an hour before bed.
• Avoid large meals and alcohol before bed.
• Limit caffeine in the afternoon and evening.
• Exercise regularly and eat a healthy diet.

How much sleep is enough

The CDC recommends the following nightly sleep for adults by age:

• Ages 18 to 60: 7 hours or more.
• Ages 61 to 64: 7 to 9 hours.
• Age 65 and over: 7 to 8 hours.

Seek help if poor sleep persists

The CDC says people who often sleep poorly, or who suspect a sleep disorder such as insomnia, should seek help from a healthcare provider. The provider may ask you to keep a sleep diary or arrange a sleep study to find the cause.

If poor sleep continues, consider seeing a healthcare provider and bringing your sleep records. This article offers general health information only and is not medical advice; consult a doctor before considering any treatment.

Prices and details correct as of November 2026

This article is general health information, not medical advice. For any health concern, consult a doctor or registered health professional.