Sex differences in sleep and sleep-dependent learning in abstinent cocaine users
ABSTRACT 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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ABSTRACT: Abrupt discontinuation of heavy marijuana (MJ) use is associated with self-reports of sleep difficulty. Disturbed sleep is clinically important because MJ users experiencing sleep problems may relapse to MJ use to improve their sleep quality. Few studies have used polysomnography (PSG) to characterize changes in sleep architecture during abrupt abstinence from heavy MJ use. We recorded PSG measures on nights 1, 2, 7, 8, and 13 after abrupt MJ discontinuation in 18 heavy MJ users residing in an inpatient unit. Across abstinence, Total Sleep Time (TST), Sleep Efficiency (SEff), and amount of REM sleep declined, while Wake after Sleep Onset (WASO) and Periodic Limb Movements (PLM) increased. Furthermore, quantity (joints/week) and duration (years) of MJ use were positively associated with more PLMs. The treatment of sleep disturbance is a potential target for the management of cannabis use disorders since poor sleep could contribute to treatment failure in heavy MJ users.Sleep Medicine 10/2010; 11(9):882-9. · 3.10 Impact Factor
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ABSTRACT: Odor identification ability is sensitive to prefrontal lobe dysfunction and preliminary evidence suggests that this capacity may decline with prolonged wakefulness. We hypothesized that declines in odor identification during a single night of sleep loss might, therefore, be predictive of prefrontal lobe executive function deficits following an additional night of sleep deprivation. Change scores between two administrations of the University of Pennsylvania Smell Identification Test (SIT) during 24 hr of sleep deprivation were used to predict performance on the Wisconsin Card Sorting Test (WCST) following 45 hr of wakefulness in 54 healthy adults. Declines in SIT performance predicted poorer performance on the WCST following an additional night of sleep loss. These findings suggest that individual differences in vulnerability to the effects of sleep loss on odor identification ability are predictive of deficits in executive functioning following additional wakefulness. Odor identification ability may provide an unobtrusive method for assessing vulnerability to sleep deprivation.The International journal of neuroscience 05/2010; 120(5):328-34. · 1.53 Impact Factor
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ABSTRACT: To describe the sleep patterns of early cocaine abstinence in chronic users by polysomnographic and subjective measures. 28 cocaine-dependent participants (ages 24-55) underwent polysomnographic sleep (PSG) recording on the 1st, 2nd and 3rd weeks of abstinence on a research dedicated inpatient facility. Objective measures of total sleep time, total REM time, slow wave sleep, sleep efficiency and a subjective measure (sleep quality) along with demographic data were collected from three different long term research studies over a five year period. Data were reanalysed to allow greater statistical power for comparisons. Progressive weeks of abstinence had main effects on all assessed PSG sleep measures showing decreased total sleep time, REM sleep, stages 1 and 2 sleep, and sleep efficiency; increases in sleep onset and REM latencies and a slight increase in slow-wave sleep time were also present. Total sleep time and slow wave sleep were negatively associated with years of cocaine use. Total sleep time was positively associated with the amount of current ethanol use. Sex differences were found with females having more total REM time and an increase at a near significance level in slow wave sleep. Subjective measures were reported as improving with increasing abstinence over the same time period. Chronic cocaine users show a general deterioration in objective sleep measures over a three-week period despite an increase in subjective overall sleep quality providing further evidence for "occult insomnia" during early cocaine abstinence.Drug and alcohol dependence 12/2010; 115(1-2):62-6. · 3.60 Impact Factor