Predicting duration of clinical stability following haloperidol withdrawal in schizophrenic patients

Although chronic maintenance antipsychotic drug treatment is the most effective way of preventing relapse in schizophrenic patients, it is not very successful. A considerable number of patients relapse on medication, and many others do not take their medications as prescribed after leaving the hospital. Unfortunately, clinicians are not able to identify how long patients will remain clinically stable after drug discontinuation. To develop a model consisting of behavioral and monoaminergic variables to identify the risk of symptom exacerbation, we obtained in the week prior to haloperidol discontinuation global behavioral ratings and cerebrospinal fluid (CSF) values for monoamine metabolites in a sample of 109 DSM-III-R schizophrenic patients. Patients were followed until specific criteria for increases in psychosis were met for up to 1 year and then returned to antipsychotic drug treatment. Cox regression analysis identified predictors of the survival function, or the probability of relapse at a given time drug free. The best model indicated that increased psychosis, decreased anxiety, an increased CSF homovanillic acid (HVA) to 5-hydroxyindoleacetic acid (5-HIAA) ratio, and decreased CSF 3-methoxy-4-hydroxyphenylglycol (MHPG) prior to haloperidol withdrawal were associated with early increases in psychosis. Our study indicates that it is possible to identify those patients who are more likely to remain clinically stable without medication. When the model is validated, it will help clinicians assess the relapse risk over time, lower doses in treatment-resistant patients, and possibly determine the optimal time for aftercare visits following hospital discharge.