Drug therapy in schizophrenia--variability of outcome and prediction of response

In spite of the proven benefits of neuroleptics in reducing acute psychotic symptoms and in preventing relapse in schizophrenic patients, not all schizophrenics benefit equally from neuroleptic therapy. Predictors of response include: demographics, clinical characteristics, neurologic soft signs, neurocognitive functioning, morphologic brain changes, drug blood levels, indices of blockade of the dopamine receptors, subjective response to medications as well as early symptomatic improvement. Methodological difficulties in outcome research in drug therapy are reviewed. No single factor has been identified as a reliable predictor of drug response, and it is unlikely that such a single predictor will prove useful in a heterogeneous illness such as schizophrenia. This paper reviews the factors, which have been suggested as useful in developing better understanding of variability of drug response among schizophrenics.