Factors in choosing atypical antipsychotics: toward understanding the bases of physicians' prescribing decisions.

OBJECTIVE Off-label prescribing of medications, polypharmacy, and other questionable prescribing practices have led investigators to examine a large VA pharmacy database to determine if physician prescribing decisions appear reasonable. METHOD The current study addresses the question of physician prescribing of atypical antipsychotics in 34,925 veterans with schizophrenia, using a series of signal detection analyses. RESULTS These results suggest that only three factors (hospital size, age, and secondary diagnosis) allow classification of patients prescribed atypicals into three groups with frequencies of use of atypicals ranging from 43% to 79%, and that these results are consistent with reasonable clinical practice. CONCLUSIONS Results of two-stage signal detection analyses are readily interpretable by clinicians and administrators who are faced with the task of evaluating how physicians prescribe medications in clinical practice. Physicians' decisions to prescribe atypical antipsychotics are based on both patient and fiscal considerations. This likely reflects a combination of clinical judgment and institutional guidelines.