Changes in sleep quality during the 12 months following medical cannabis initiation

Poor sleep quality is a commonly reported reason for medical cannabis (MC) use, yet evidence regarding its long-term impact on sleep remains limited. This study evaluated changes in subjective sleep quality over a 12-month period among adults initiating MC treatment in Pennsylvania and explored whether preferred route of administration and referring condition were associated with observed changes.

A total of 137 adults newly referred for MC in PA completed the Pittsburgh Sleep Quality Index (PSQI) at baseline and at 3, 6, 9, and 12 months. Linear mixed effects models assessed changes in PSQI global and subscale scores over time. Additional models evaluated whether preferred administration route (oral vs. other) and referring condition (chronic pain, anxiety, PTSD) were associated with differences in observed outcomes.

Global sleep quality scores, where higher values indicate poorer sleep quality, were significantly higher at baseline than at each follow-up point (p < .0001), with no significant differences among follow-up assessments, suggesting early and sustained improvements in self-reported sleep quality. Improvements were observed across all PSQI subscales. No significant relationships were found between sleep quality scores and either administration route or referring condition.

These findings suggest that MC may be associated with improvements in subjective sleep quality, though its impact did not vary as a function of administration route or primary referring condition. Additional research using objective sleep measures and controlled designs is needed to clarify MC's role in sleep quality.