UC San Diego

Marijuana is the most commonly used recreational drug in the United States. Research on the relationship between marijuana and sleep is still in its infancy. The study examined differences in sleep characteristics between a community sample of daily users, non-daily marijuana users, and non-users. A total of 98 subjects (45 M; 53 F) participated. The mean age was 22.3 (standard deviation = 3.0). There were 53 females and 55% of the sample was Caucasian. Recruitment was done online and via print advertisements in the community. Groups were categorized as non-daily users (n = 29), daily users (n = 49), and non-user controls (n = 20). Sleep was characterized by the Pittsburgh Sleep Quality Index, Insomnia Severity Index, Epworth Sleepiness Scale, and the Morningness Eveningness Questionnaire. A standard cut off score of >10 for the Insomnia Severity Index was found in 38.8% of daily users, 10.3% of non-daily users, and 20% of non-users. Pittsburgh Sleep Quality Index scores in daily users (7.0+/-3.8) were higher than non-daily (4.9+/-3.2) and non-user controls (5.0+/-3.7), p = .02. Insomnia Severity Index scores in daily users (7.9+/-6.1) were higher than non-daily (5.1+/-4.3) and non-user controls (4.3+/-4.8), p = .01. Covariate adjusted regression analyses revealed mean Pittsburgh Sleep Quality Index and Insomnia Severity Index scores were significantly lower for non-daily users and controls relative to the daily users. When adjusting for depression and anxiety, these unique associations were not significant. There were no differences in the Epworth Sleepiness Scale or Morningness Eveningness Questionnaire. Daily marijuana users endorsed more sleep disturbance than non-daily users. Future studies should consider mood in the relationship between marijuana use and sleep.