Severity of tardive dyskinesia (TD) and psychopathology of 36 chronic schizophrenic patients under long-term treatment with neuroleptics (NL) was rated during NL therapy and again 12 days after NL withdrawal. Both times serum levels of prolactin, norepinephrine, beta-endorphin, and cortisol were determined. In 27 of these patients ventricular-brain ratio, width of third ventricle, maximal width of anterior horns, distance between choroid plexus, and width of four largest sulci were also measured. Fifteen patients had no signs of TD; 14 had moderate, and 7 severe TD. TD was not related to age, age at onset of illness, duration of illness, dosage and type of neuroleptics, number of ECTs, or any endocrine variable. Psychopathology was barely related to TD, but after NL withdrawal, patients with TD tended to show more deterioration, particularly with regard to thought disorder and activation. With regard to computer-tomographic (CT) variables, patients without TD showed significantly less sulcal enlargement than those with TD. These results indicate that individual predisposition, which may have led to the development of TD, also seems to involve a higher risk of relapse after NL withdrawal.