Depressive symptoms frequently occur in patients with a primary diagnosis of schizophrenia. Depressive symptoms can be differentiated from negative symptoms and occur in all phases of schizophrenia. Some pathogenetic hypotheses about these symptoms are described. In this review, research about the therapeutic efficacy of tricyclic antidepressants in schizophrenia is surveyed and summarized. Depressive symptoms can be the expression of an akinetic depression. The effect of anticholinergic medication should be evaluated first. Patients who are not actively psychotic and who develop depressive symptoms in the course of schizophrenia, scoring 17 or more on the Hamilton Rating Scale for Depression might benefit from adjunctive antidepressants. Negative symptoms as such do not ameliorate. Monotherapy with antidepressants is not supported by the results of the reviewed studies. Exacerbation of psychotic symptoms remains a considerable risk.