The impact of premorbid social and intellectual functioning in childhood and early adolescence on the developmental course of schizophrenia is not sufficiently understood. In a retrospective case study (93 consecutive in-patients, 43 males and 50 females) of first-episode psychosis occurring in adolescence, the relationship between premorbid adjustment and short-term therapeutic outcome under treatment conditions was examined. All of the patients had a DSM-III-R diagnosis of schizophrenia (n = 56) or schizo-affective disorder (n = 37). The mean age of the patients at the time of the study was 15.8 (SD = 1.0). Premorbid functioning during childhood and early adolescence was assessed by using the Cannon-Spoor et al. Premorbid Adjustment Scale (PAS) and studied with respect to its prognostic relevance for short-term therapeutic outcome (eight weeks) under neuroleptic treatment (350-700 mg Chlorpromazin dose equivalent). Criteria for clinical outcome were obtained from the study by Pearlson et al. (1989) which defines three grades (complete remission, partial remission and no response), according to the degree of positive symptomatology. Statistical analysis was based on nonparametric variance analysis. Patients with complete remission of positive symptoms after eight weeks of therapy had experienced far better premorbid adjustment in early adolescence and in childhood. Diagnosis and gender did not bias this result. Our data suggest that premorbid social functioning is a crucial variable with regard to therapeutic outcome in first-episode psychosis. Previous studies have reported a relation between poor premorbid functioning and negative symptoms. We found premorbid adjustment related to the course of positive symptoms.