90 patients with schizophrenia, schizoaffective or schizophreniform disorder, or psychotic disorder NOS (not otherwise specified) will be included, with an age of 18-70 years and a time interval between the onset of psychosis and study entry not exceeding seven years. All 90 in- and outpatients will be randomized 1:1 to either prednisolone or placebo daily for 6 weeks. Prednisolone will be initiated at 40mg/day for 3 days and the 4 remaining days of the first week 30mg/dag will be used. During the treatment period, patients will be seen at weekly intervals to assess symptom severity, depressive mood and suicidal ideation, global functioning and side effects.