One hundred and twenty-nine cases of Wilson's disease (WD) were assessed at index admission and two follow-ups (F1 and F2) on a range of clinical and biochemical variables. The commonest psychiatric symptoms throughout were incongruous behavior, irritability, depression, and cognitive impairment. Among psychiatric cases, most improvements occurred in the interval index-F1, with subsequent leveling off. Significant improvement occurred only with incongruous behavior and cognitive impairment. Psychiatric cases whose psychiatric symptoms persisted to F2 differed from those who responded, in particular showing more dysarthria, incongruous behavior, and hepatic symptoms. Neuropsychiatric cases displayed more dysarthria and incongruous behavior than patients with neurological symptoms alone. Further evidence for associations between dysarthria and abnormal behavior emerged from this study.