Relationship of extrapyramidal symptoms to age at onset and drug treatment in middle-aged and elderly schizophrenic patients.

The relationship between antipsychotic drugs and dyskinesias and other extrapyramidal symptoms (EPS) in schizophrenia is not simple. There is a need to study variables that may influence the occurrence of EPS in schizophrenic patients receiving drugs. The present study examined the relationship of age at onset of illness and treatment to the development of EPS in 122 middle-aged and elderly schizophrenic patients, 84 treated and 38 who had never received antipsychotic drugs. The illness had an early onset (before 45years, EOS) in 68 patients and a late onset (after 45years, LOS) in 54 patients. The patients were evaluated for dyskinesia and parkinsonism using abnormal involuntary movements scale (AIMS) and Simpson-Angus scale. The prevalence of dyskinesia and parkinsonism was similar in all the patient groups. The scores on limb-axial and severity subscales of AIMS were significantly higher in the treated than the untreated patients of the early onset group. This was not so with the late onset patients. The total parkinsonism score was higher among the treated, notably the LOS patients. The development of dyskinesia and parkinsonism in schizophrenia is possibly related to the age at onset of the illness. In late onset forms the ageing of the patient and a possible neurological abnormality related to schizophrenia might enhance the EPS-inducing effect of drugs.