Sleep disturbances are associated with reduced health-related quality of life in patients with substance use disorders.

BACKGROUND AND OBJECTIVES: Sleep problems and substance use are strongly linked. Sleep problems play a role in the etiology of substance use, but also may be a result of it. After detoxification, sleep problems may worsen leading to relapse. Nowadays, most substance dependence treatment programs aim at recovery rather than total abstinence, and in that view health-related quality of life (HRQL) is a relevant construct. This article describes the association between self-perceived sleep problems and HRQL in a naturalistic population of polydrug-using inpatients. METHODS: At the start of treatment, 388 polydrug-using inpatients completed questionnaires concerning their sleep quality and HRQL. Three categories were established based on reported sleep problems: patients without sleep problems (21.6%), those with clinically relevant sleep problems (34.5%), and patients with sleep disorders (43.8%). RESULTS: Mean grades for quality of sleep were M = 7.3 (sd 1.7), M = 6.6 (sd 1.7) and M = 5.3 (sd 1.9) for the three categories, respectively. In addition, patients in the disorder category perceived a lower HRQL than those in the other categories. In the explanation of HRQL, both sleep problems and sleep disorders added significantly to the model when controlling for baseline characteristics. DISCUSSION AND CONCLUSIONS: Our findings stress the need for clinicians to pay attention to the quality of sleep of recovering polydrug users, since this may play an important role in the recovery process. Monitoring sleep during treatment is advocated. This study adds to the knowledge about the way HRQL and sleep are related in a naturalistic sample of substance-dependent patients.

Large-scale ensemble averaging of ambulatory impedance cardiograms.

Impedance cardiography has been used increasingly to measure human physiological responses to emotional and mentally engaging stimuli. The validity of large-scale ensemble averaging of ambulatory impedance cardiograms was evaluated for preejection period (PEP), interbeat interval, and dZ/dt(min) amplitude. We tested whether the average of "classical" 60-sec ensemble averages across periods with fixed activity, posture, physical load, social situation, and location could be accurately estimated from a single large-scale ensemble average spanning these entire periods. Impedance and electrocardiograms were recorded for about 24-h from 21 subjects. Recordings were scored by seven raters, using both methods for each subject. Good agreement (average intraclass correlation coefficient was .91) between both ensemble averaging methods was found for all three cardiac function measures. The results indicate that for unambiguous ambulatory impedance cardiograms, large-scale ensemble averaging is valid, which makes measuring prolonged changes in cardiac sympathetic activity by measuring ambulatory PEP feasible even in large epidemiological samples.