Differential diagnosis and different etiologies of monopolar and bipolar phasic psychoses

Monopolar and bipolar phasic psychoses can be differentiated not only on the course but also on the symptom pattern. This applies also to the euphoric forms which usually are still assigned to Manic-depressive illness. The differential diagnosis is presented. Aetiology is completely different in the monopolar and the bipolar phasic psychoses. Manic-depressive illness has a hereditary basic, whereas in the monopolar ("pure") forms loading is very low. Particularly few psychoses among the relatives have been found in the euphoric forms which demonstrates their independency for if they would belong to Manic-depressive illness they necessarily would show the heavy genetic loading of this bipolar illness. In the pure phasic psychoses external causes were detected when we focused on the sibships in which the probands had grown up. The euphoric patients had relatively many older siblings, the depressive ones relatively few older siblings. A similar difference was found in two cycloid psychoses. Transcultural observations as well as shifts in the incidence rate of the psychoses in our times confirmed our results. Prophylactic measures can be derived.