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Background. The importance of sleep for memory consolidation has become a major focus of research. While it is known that abstaining alcohol-dependent patients often have sleep disorders and that there is some cognitive impairment during early abstention a possible interaction of disturbed sleep with overnight memory consolidation has not been addressed in a study as yet. Methods. Twenty-four alcohol-dependent patients with a short abstention period (mean 21.9 ± 7.6 days) were compared with 12 patients with an abstention period of several months (115.7 ± 43.8 days). Groups did not differ with respect to daily alcohol consumption before treatment, duration of alcohol dependence, and age. Before sleep all patients learned a list of semantically associated word pairs and a face name association task to a fixed criterion (at least 60% of correct recall) and they performed a mirror tracing task. After a polysomnographically registered night the patients were tested for retention of the learned declarative material by cued recall and had to perform the mirror tracing task again. Results. The groups did not differ with respect to sleep parameters or sleep-associated memory consolidation. Across both groups the duration of alcohol dependence correlated negatively with the amount of non-REM sleep and recall in the face name association task correlated negatively with daily alcohol consumption before abstention. Among the longer-term abstainers the duration of abstention correlated with the amount of slow wave sleep. Conclusions. Our data support the hypothesis that chronic and high alcohol consumption negatively affects sleep and declarative memory consolidation during the first months of abstention. Between an abstention period of a few weeks and of several months no change in sleep parameters and nightly memory consolidation could be demonstrated, however.

Hypothalamo-pituitary-adrenocorticoid (HPA)-axis reactivity to psychosocial or pharmacological stimulants is diminished in alcohol-dependent patients during early abstinence but recovers after several months of abstention. In order to assess the physiological reactivity in the morning we used the cortisol awakening response (CAR) in saliva to compare 24 early abstainers (mean 21.9+/-7.6, range 10-36 days) with 12 alcohol-dependent patients with longer abstention periods (mean 116.8+/-45.7, range 59-230 days) and looked for an association with sleep, especially rapid eye movement (REM) sleep of the preceding night. Both groups did not differ with respect to age, duration of alcohol dependence, daily drinking dosage before detoxification, body mass index, depressivity, level of anxiety, daily cigarette consumption or sleep quality during the preceding 14 days. Sleep in the night before cortisol assessment did not differ with respect to total sleep time (412.4+/-35.9 vs. 407.0+/-38.7 min). Immediately upon awakening and 15, 30, 45 and 60 min later, specimens of salivary cortisol were collected. While starting from equal levels upon awakening longer abstaining patients with alcohol dependence showed a stronger CAR (ANOVA with repeated measurement, time x group effect: F=4.33, p0.01) with distinctly higher cortisol levels 45 and 60 min after awakening (T=3.79, p0.001 and T=3.06, p0.005, respectively). Across both groups the time spent in REM-sleep only correlated with cortisol levels upon awakening (r=0.33, p0.05). Our data indicate that CAR is a useful tool for investigating alterations in the HPA-axis regulation in abstaining alcohol-dependent patients.