- For a significant portion of time since the onset of the disturbance, level of functioning in one or more major areas, such as work, interpersonal relations or self-care, is markedly below the level achieved prior to the onset.
- Continuous signs of the disturbance persist for at least six months.
- Schizoaffective disorder and depressive or bipolar disorder with psychotic features have been ruled out because either no major depressive or manic episodes have occurred concurrently with the active-phase symptoms or, if mood episodes have occurred during the active-phase symptoms, the episodes have been present for a minority of the total duration of the active and residual periods of the illness.
- The disturbance is not attributable to the physiological effects of a substance.
If a history of autism spectrum disorder or a communication disorder of childhood onset exists, the additional diagnosis of schizophrenia is made only if prominent delusions or hallucinations in addition to the other required symptoms of schizophrenia are also present for at least one month.