The importance of nonverbal behaviour displayed by psychiatric patients has been outlined in this article, in particular with regard to depression. Various interactional models are proposed, explaining the cause and the maintenance of depression by interpersonal processes between (potential) patients and their social environment. In this context verbal as well as nonverbal behaviour are of interest. The article gives an overview of functions of nonverbal behaviour probably being of importance for depression (i.e., behaviours which may express depressed mood, anxiety, tension and/or involvement). Next, an overview of research is presented concerning the relationship between depression and nonverbal communication. The results are interpreted in terms of the aformentioned possibly disturbed functions. It is concluded that information of nonverbal communication may be an useful tool in the diagnostic process, in evaluating clinical change, and as predictor of prospects of depressed patients.