A series of 195 cases of Wilson's disease were assessed retrospectively on a range of variables, including psychiatric, neurologic, and hepatic symptoms, and biochemical data as recorded at first admission to a specialist clinic. Ninety-nine patients (51%) were rated as displaying some evidence of psychopathologic features, and 39 (20%) had seen a psychiatrist before the diagnosis of Wilson's disease. The most common psychiatric features were abnormal behavior and personality change, although depression and cognitive impairment were also rated frequently. Schizophrenialike psychoses were rare, apparently occurring at no more than chance frequency. Psychiatric symptoms were related to neurologic rather than hepatic symptoms, and certain symptoms (incongruous behavior, irritability, and personality change) had a particularly significant relationship with bulbar and dystonic disorders but not with tremor. Psychiatric manifestations are important in Wilson's disease, and many of the psychopathologic features seem to have an organic basis.