Recreational Cannabis Use Was Linked to Worse Sleep Across 120 Studies

Across 102 observational studies, current recreational cannabis use was associated with poorer sleep quality, both short and long sleep duration, more insomnia symptoms, and a later chronotype compared to non-use. These associations were stronger in men and younger users. However, 19 experimental studies found no associations between cannabis use and sleep quality or duration.

Systematic review and meta-analysis of 120 studies identified from six databases. Studies on medicinal cannabis and clinical samples were excluded. Current use was defined as use within one month; lifetime use as use in the past year or lifetime. The analysis separated observational and experimental evidence.

Many people use cannabis specifically to improve sleep, yet this large-scale synthesis of the general population evidence suggests recreational use is actually associated with worse sleep outcomes. The disconnect between observational and experimental findings highlights the complexity of the cannabis-sleep relationship.

The gap between observational and experimental findings could mean that poor sleepers are more likely to use cannabis (reverse causation) or that confounding factors like stress and mental health problems drive both cannabis use and poor sleep. Long-term trials are needed but face ethical and practical barriers.

Observational studies cannot establish causation. The experimental studies were relatively short-term and may not capture chronic effects. Excluding medicinal cannabis users and clinical samples limits generalizability to people using cannabis specifically for sleep problems.