The study comprises a retrospective evaluation of the case records of 49 first-admission patients with acute reactive paranoid psychosis and of the subsequent follow-up almost 10 years later, with special reference to clinical and social course and outcome. Ten of the 41 followed-up patients were diagnosed schizophrenic in the observation period and a further five fulfilled the Catego Class S+ at a PSE interview. Three patients were diagnosed affective psychosis and one fulfilled Class M?. Three patients were diagnosed paranoid psychosis and four more fulfilled Class P+/P? while six patients had reactive psychosis relapses but were non-psychotic at follow-up. During the observation period the number of disabled pensioners increased from three to 21, and at follow-up only seven patients were well-adjusted in their family and work. The need is stressed for valid predictors in the prognosis of acute paranoid psychoses with or without associated stressful life events.