Sleep quality deteriorates over a binge--abstinence cycle in chronic smoked cocaine users

In cocaine dependent individuals, changes in subjective and objective sleep quality accompany their characteristic binge-abstinence cycle. Preliminary studies suggest that sleep quality may decline with prolonged abstinence. Reported here are results of the most extensive study to date on sleep abnormalities during cocaine binge and confirmed abstinence under controlled conditions.

The purpose of the current study was to use an experimental, inpatient model of the cocaine binge and abstinence cycle to examine the course and magnitude of sleep disturbances during cocaine use and abstinence.

Five inpatient non-treatment seeking cocaine users completed 3 baseline days of drug abstinence followed by 3 days of medically monitored "binge" cocaine use, and then 15 days of drug abstinence. Physiological sleep was recorded with polysomnography and the Nightcap ambulatory monitor, while subjective sleep was assessed by questionnaire.

Across 3 days of binge cocaine use and 15 subsequent days of confirmed drug abstinence, mean sleep duration, efficiency and latency changed in the direction of poorer sleep quality. In contrast, subjective reports of sleep quality remained unchanged across the same period.

Physiological sleep quality deteriorated from days when cocaine was used across the first 2 weeks of confirmed drug abstinence. In contrast, subjective reports of sleep quality remained unchanged across the same period. We postulate that this dissociation between objective and subjective sleep quality results from a cocaine-use related disruption of the sleep homeostat. Worsening sleep quality during cocaine abstinence may contribute to the risk of relapse and its treatment may offer novel therapeutic strategies for cocaine dependence.