THE EVOLUTION OF TREATMENT RESISTANCE - BIOLOGIC IMPLICATIONS

The evolution of resistance of positive symptoms to antipsychotic ther apy may represent a valuable means of subtyping schizophrenia. In cont rast, resistance of negative symptoms and cognitive function to antips ychotic agents seems to be present from the first episode of psychotic symptoms and does not evolve over time to the same extent. If these f indings are validated, this clearly points toward differences in the e tiology of these components of schizophrenia. Data from a cohort of 22 3 patients with unsatisfactory responses to classical antipsychotic th erapy are evaluated, at least 60% of whom responded to subsequent trea tment with clozapine. Comparisons were made between the subgroups of p atients with primary and delayed onset treatment resistance. Both subg roups responded to clozapine therapy, although better response was evi dent for patients with delayed resistance. The withdrawal of clozapine from patients who had previously been responsive to classical antipsy chotic therapy was capable of inducing treatment resistance.