OBJECTIVE: The authors attempted to replicate previous findings of relationships of CSF dopamine beta-hydroxylase with premorbid functioning and computerized tomography (CT) scan measures in a new cohort of schizophrenic patients. METHOD: Data on CSF dopamine beta-hydroxylase-like immunoreactivity and premorbid functioning, as well as CT scans, were obtained in 60 drug-free, male schizophrenic patients and two groups of normal comparison subjects. RESULTS: CSF dopamine beta-hydroxylase did not differ between the comparison subjects and schizophrenic patients. Lower CSF dopamine beta-hydroxylase was associated with better premorbid social functioning and with less prefrontal sulcal widening. Better premorbid school functioning and more years of education, however, were associated with higher CSF dopamine beta-hydroxylase. CONCLUSIONS: The association between low CSF dopamine beta-hydroxylase and premorbid functioning was confirmed for social functioning, while the opposite was observed for scholastic performance, suggesting that these are different dimensions. Dopamine beta-hydroxylase modulates the prognosis and potentially the course of schizophrenia without necessarily causing the disorder.