A patient has continuous psychotic symptoms for more than six months with a decline in work and social functioning, and at least one month of hallucinations and disorganized speech, with substance use and medical causes ruled out. What is the diagnosis?

• A. Schizophrenia
• B. Schizoaffective disorder
• C. Brief psychotic disorder
• D. Delusional disorder

Answer: (A)

The key idea here is the duration and pattern of psychotic symptoms used to diagnose schizophrenia. Schizophrenia requires continuous psychotic symptoms for more than six months, with at least one month of active-phase symptoms (such as hallucinations or disorganized speech) and clear impairment in work, social functioning, or self-care. In this case, the patient has ongoing psychotic symptoms for longer than six months and has at least one month of hallucinations and disorganized speech, plus a decline in functioning. With substance use and medical causes ruled out, this pattern fits schizophrenia rather than other psychotic disorders. Brief psychotic disorder is too short (less than one month), schizophreniform is 1–6 months, delusional disorder centers on non-bizarre delusions with relatively preserved functioning and little disorganization or hallucinations, and schizoaffective disorder requires mood symptoms concurrent with psychosis in a substantial portion of the illness. So schizophrenia is the best fit.