Predictors of therapeutic response to haloperidol in acute schizophrenia.

During a study of neuroleptic threshold haloperidol doses as treatment for newly admitted schizophrenic patients, we examined whether variables extracted from patients' clinical histories, the type and severity of patients' psychopathology at baseline, or the emergence of specific extrapyramidal side effects (EPSE) during treatment were associated with therapeutic response. Rapid therapeutic response was most powerfully predicted by a short (less than 1 month) duration of active illness prior to admission. Severe psychopathology at baseline, or the development of akathisia at neuroleptic threshold doses, portended against early response. More gradual therapeutic response was also associated with limited (less than 6 months) duration of active illness prior to admission. Motor retardation at baseline also characterized late responders. Active illness for more than 6 months prior to admission, greater chronicity of overall course, and heavy nicotine consumption characterized nonresponders.