Sleep disturbances, especially insomnia, may be caused by a broad range of psychiatric disorders, in particular by mood and psychotic disorders, anxiety disorders, dementia, substance related and personality disorders. Depression is the most frequent cause of insomnia. The group of anxiety disorders consists of phobic disorders, panic disorder, generalized anxiety disorder, and combined fear and depression. Women are more than twice as likely as men to develop posttraumatic stress disorder (PTSD) after exposure to a psychological trauma. The lifetime prevalence of schizophrenia has been reported as ranging from 1% to 2%, and about 0.025% to 0.05% of the total population is treated for schizophrenia in any single year. Sedating neuroleptics may be suitable for treatment of sleep disturbances because these substances are well tolerated and may positively influence both insomnia and anxiety/confusion with only minor hangover effects.