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P039 REM sleep and dream reports in frequent cannabis versus non-cannabis users
  1. Ceri Bradshaw,
  2. Rebecca Borcsok,
  3. Matthew Taylor,
  4. Sophie Segust,
  5. Daniel Ford and
  6. Michelle Carr
  1. Swansea University, Swansea, UK


Tetrahydrocannabinidiol (THC; one of the main psychoactive components of cannabis) has been shown to suppress REM sleep1-4 and affect sleep latency,4 5 although these findings are not consistently replicated.3 4 6 Cannabis use is also reported to affect dreaming frequency.7 Most studies investigating cannabis use and sleep have been laboratory-based, while only a limited body of research exists on dream occurrence and cannabis use. This study aimed to pilot the measurement of participants sleeping at home in their usual surroundings, in order to assess effects of cannabis use compared to non-use, on objective sleep measures, dream reports, and self-reported anxiety, memory, and sleep quality. Eleven frequent cannabis users versus 8 non-users proceeded in their usual routines, and wore Hypnodyne Zmax portable sleep acquisition headbands (recording EEG, EOG and EMG) while sleeping at home over two consecutive nights. Participants gave dream reports in three awakenings, set at two-hourly intervals on each night, and once upon morning awakening, reporting dream content and subjective ratings of the dream’s bizarreness, emotionality, and sensory experience. In addition, participants completed problem cannabis use, lifetime and nightly cannabis use, PSQI, everyday memory and trait anxiety measures. No differences were reported by participants in sleep quality, anxiety or memory between the two groups; predictably, cannabis users reported significantly more problems in relation to use of the drug. Cannabis users demonstrated significantly longer sleep latency and less REM sleep overall; no other differences occurred in objective sleep measures between groups. Cannabis users reported higher bizarreness in their dreams, but no differences were reported in dream recall or other dream measures. It is noted that small sample sizes limit the generality of findings in this study. The procedure provides a useful paradigm and encouraging initial results, however, for contemporary research related to cannabis use and sleep in naturalistic conditions, in this ongoing project.


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