This psychotic mental disorder is diagnosed when prominent nonbizarre delusions are present for at least one month and the symptom criteria for Schizophrenia have never been met. Hallucinations may be present, but auditory or visual hallucinations cannot be prominent. Olfactory or tactile hallucinations may be prominent, but only if they are related to the content of the delusion. Psychosocial functioning may not be impaired and any co-occurring mood episodes must be of relatively brief duration.