Efficacy and effectiveness of first- and second-generation antipsychotics in schizophrenia.

While efficacy as a concept is concerned with whether a treatment works under ideal conditions, effectiveness is concerned with whether a treatment works under the conditions of routine care. Large-scale clinical, pharmacy, and administrative databases can provide naturalistic data for effectiveness studies when appropriate methodology is employed. The Nathan Kline Institute Integrated Research Database includes patient-specific admission, demographic, diagnostic, medication, and discharge information from hospitals operated by the New York State Office of Mental Health. This database was used to study the effectiveness of first- versus second-generation antipsychotics in the treatment of schizophrenia and schizoaffective disorder. Switching off the index medication regimen prior to discharge (negative outcome) was our principal outcome of interest. We concluded that, as a class, second-generation antipsychotics were less likely than first-generation agents to be associated with premature discontinuation of an antipsychotic regimen, both when used as the initial medication regimen following hospitalization and as the second regimen following a prior medication switch.