Diagnostic criteria

The criteria for the diagnosis of schizophrenia outlined by the American Psychiatric Association are outlined below:

• the patient exhibits characteristic symptoms (flat or grossly inappropriate affect, delusions, marked loosening of association) for a period of greater than or equal to one week.
• there is a marked deterioration in work and/or social relations and/or self-care during the course of the illness.
• if there is an affective component to the illness then the episodes are brief in comparison to the psychotic component.
• a six month period with signs of the disturbance. The period must contain periods of at least one week where there are episodes of characteristic psychotic symptoms - this period must be combined with a prodromal period (a period where there is a clear deterioration in functioning before the active phase of the disturbance) or a residual phase (a period of reduced function following the active phase of the disturbance).
• no organic factor can be identified that initiated and maintained the disturbance.
• if the patient has a history of autism then a diagnosis of schizophrenia can only be made if there are prominent hallucinations or delusions present.