An ever-increasing interest in the effects of psychotropic drugs on the sleep elecrtoencephalogram (EEG) in humans has developed, resulting in a number of new works in this field. In this review, we are only going to mention the most important results. After the administration of different psychotropic agents such as neuroleptics, antidepressants, antimanics, aniolytics and hypnotics, the different results' can bu obtained in sleep EEG, respectovely. All these effects on the sleep EEG in humans are dependent on several factors : (1) the type of psychotropic drugs