Switching from conventional to novel antipsychotic drugs: results of a prospective naturalistic study.

Objective: We examined the long-term consequences of switching patients from conventional to novel antipsychotic drugs, from a patient's perspective.

Methods: In a prospective, single-blinded, naturalistic study, a cohort of subjects (n=150) with schizophrenia or schizo-affective disorder (DSM-IV) were switched from conventional neuroleptic drugs to either risperidone (n=50), olanzepine (n=50) or quetiapine (n=50), and monitored for a period of 2 to 6 years. The ensuing natural history of transitions in treatments was charted, and the outcomes including symptoms, side effects, subjective tolerability of drugs and their impact on quality of life were documented with standardized rating scales.

Results: Majority (85%) of the subjects benefited from a switch to the novel antipsychotic drugs, though some preferred to return to their original neuroleptic (8%), and others eventually required clozapine (7%) therapy. Novel antipsychotic drugs were significantly tolerated better, and had a positive impact on treatment-adherence, psychosocial functioning and quality of life. Among the novel drugs, risperidone was significantly better in improving negative symptoms, while olanzepine was particularly well tolerated and effective against comorbid anxiety and depressive symptoms. Patients treated with quetiapine reported fewer side effects, and showed a significantly greater improvement in neurocognitive deficits.

Conclusion: Novel antipsychotics emerged as the drug of choice in view of their overall effectiveness, though conventional neuroleptics and clozapine will continue to have a limited but distinct role in the management of schizophrenia. The challenge for clinicians lies in matching a patient's clinical and biochemical profile with that of a drug's pharmacological actions, in order to achieve optimum outcomes.