[The neurobiology of anhedonia. The pathophysiology of an important symptom in depressive disorders].

The phenomenon of anhedonia, the inability to experience pleasure, is one of the essential elements for the diagnosis of depressive disorders. According to the criteria of both the ICD-10 and the DSM-IV, the presence of this symptom is crucial for the diagnosis of depressive disorders. In recent years scientific approaches using animal studies and projects of functional imaging have allowed the development of a new concept of the pathophysiology of anhedonia. The hypothesis that functional changes within the mesolimbic reward system could represent the neural correlate of anhedonia has contributed to a new concept of depressive disorders and allows testing of new therapeutic options for patients suffering from very resistant forms of depression. By using the method of deep brain stimulation present clinical studies try to ascertain whether the symptom of anhedonia can be alleviated by influencing the neural activity of the reward system. This article will give a critical overview about the background for new therapeutic approaches and illuminates the results of these studies.