Sex differences in sleep and sleep-dependent learning in abstinent cocaine users

Department of Psychiatry, Yale University, New Haven, Connecticut, United States
Pharmacology Biochemistry and Behavior (Impact Factor: 2.78). 07/2009; 93(1):54-58. DOI: 10.1016/j.pbb.2009.04.006


Sleep and sleep-dependent learning are impaired in male cocaine users during abstinence, but for female users little is known. Cocaine dependent men (n = 12) and women (n = 14), and control participants (n = 19) participated in this study of sleep and sleep-dependent learning. Cocaine users were assessed at 3, 10 and 20 days of abstinence and controls were studied over one night. Total sleep time, sleep efficiency and overnight motor learning were the main outcome measures. Cocaine dependent men compared to women exhibited deteriorations in sleep time, sleep efficiency, and overnight learning as abstinence progressed from 3 to 20 days. At abstinence day 3, cocaine dependent men and women were no different than control participants in the main outcomes. However, there were significant differences between cocaine men at abstinence day 20 and controls in sleep time and sleep-dependent learning, but no differences between controls and cocaine dependent women. There is growing evidence that sleep disturbances are associated with cocaine abuse and abstinence and have functional consequences that may be relevant to the development of effective treatments. The absence of sleep disturbances in women suggests a need to understand the mechanisms underlying these differences, as such knowledge could lead to novel therapies in cocaine dependence.

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    • "Despite having only five females in this sample, gender related differences were found with females having longer total sleep time and REM sleep time compared to their male counterparts. This is the first polysomnographic evidence of a gender difference in sleep in cocaine dependence and is consistent with non-polysomnographic findings (Morgan et al., 2009). While this finding should be confirmed in a larger sample, such differences, if real, could be significant in determining future sleep-related treatment options. "
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