Involuntary disorders of movement in chronic schizophrenia--the role of the illness and its treatment.

The prevalence and distribution of involuntary movements in age-matched chronic schizophrenics treated and not treated with neuroleptics were compared. While exposure to neuroleptic drugs in the past was important, high rates of movement disorder were associated with the severe, untreated illness. Ventricular enlargement correlated with severe movement disorder but not with past neuroleptic exposure. It is suggested that in the context of Schizophrenia neuroleptic drugs may act to promote what are features of the illness for some, and that in the search for predisposing factors illness, as well as treatment variables, is worthy of consideration.