Psychoses are relatively frequent disorders; around 1% to 2% of the total population are taken ill from these once in life. Currently, more than 51 million people worldwide are suffering from schizophrenia alone. Translated to a large city such as Hamburg with its 1,8 million inhabitants, this means that at present there are around 18,000 to 36,000 people suffering from psychoses there. Extrapolated to the whole of Germany, here around 800,000 to 1,6 million people are affected. The age at the first onset of the disorder is mostly between 15 and 25 years, i.e. youngsters and young adults are more frequently affected. Around 20% of persons afflicted are still in adolescence during the first psychosis. In this age spectrum, three out of 100 persons are taken ill. Psychoses therefore occur more frequently than diabetes.