Clinical state, plasma levels of haloperidol and prolactin: a correlation study in chronic schizophrenia

Chronic schizophrenic patients were maintained for six months on a dosage of haloperidol adjusted to give optimum clinical effect. A correlation was found between extrapyramidal symptoms and prolactin levels and also between plasma haloperidol concentration and plasma prolactin levels. Estimation of plasma prolactin would be a reliable measurement of patients' compliance with medication.