Sleep is not one outcome
Studies may measure time to fall asleep, total sleep time, awakenings, subjective quality, daytime function, or sleep disturbance caused by another condition. These outcomes are related but not interchangeable.
Earlier reviews often enrolled people with chronic pain and found small average changes in subjective sleep measures. That evidence does not directly establish a treatment for primary insomnia.
What the latest synthesis changes
A 2026 Cochrane review concluded that medical cannabis may have little to no clinically meaningful effect on sleep quality, total sleep time, or daytime functioning for insomnia, with very low-certainty evidence and substantial variation among studies.
Adverse events and next-day impairment remain relevant even when a person reports easier sleep onset. Short trials also reveal little about tolerance, withdrawal-related sleep disruption, or long-term outcomes.
A better interpretation
Cannabis should not be described broadly as a proven sleep treatment. The evidence depends on the sleep disorder, underlying condition, cannabinoid formulation, follow-up period, and outcome. Persistent sleep problems warrant assessment of their cause and established treatment options.