[Alcohol dependence and depression. Classification, comorbidity, genetic and neurobiological aspects]

The frequent comorbidity of psychiatric disorders and alcohol dependence has raised increasing interest in the scientific literature over the last few years. Special attention has been given to the coincidence of depressive syndromes and alcohol dependence. Depressive syndromes can both precede and follow the onset of alcohol dependence. Their diagnostic classification can cause considerable problems. In clinical studies, very different prevalence rates of depressive syndromes in alcohol-dependent persons were found. The frequency of primary depressive syndromes appeared to be substantially smaller than the frequency of secondary depressive syndromes. Epidemiological studies did not point at the exceedingly high comorbidity of affective disorders and alcohol dependence. In this review article, scientific results about possible causes of depressive syndromes in alcohol-dependent persons are demonstrated; genetic and neurobiological links between depression, alcohol dependence and the possible importance of changes in serotoninergic transmission are discussed; methodological problems are described, and implications of the comorbidity problem for treatment planning are presented.