A longitudinal study of drinking and depression as predictors of insomnia in alcohol-dependent individuals.

Insomnia and depressive symptoms are common symptoms among alcohol-dependent (AD) patients. AD individuals (N = 364) were assessed during 2004-2009 in the Midwestern United States at baseline and 6-month intervals with the Sleep Problems Questionnaire, Time-Line Follow-Back interview, and the depression subscale of the Brief Symptom Inventory. Hierarchical Linear Modeling was used to analyze the data in this longitudinal study. When modeled separately, both quantity of drinking (p < .01) and depression (p < .001) predicted insomnia severity, controlling for time, age, and gender. Drinking also predicted depressive symptoms (p < .001), and its effect on insomnia was mediated by depression severity (p < .001).