Initial treatment choice in depression: impact on medical expenditures.

<bold>Objective: </bold>The purpose of this study was to examine the economic outcomes associated with initial treatment choice following a diagnosis of depression.<bold>Methods: </bold>Insurance claims data were used to classify patients into one of 4 treatment cohorts: no therapy, psychotherapy, drug therapy and combination therapy. Potential sample selection bias was accounted for by using a 2-stage econometric estimation procedure where initial treatment choice was estimated using a multinomial logistic regression model in the first stage, and total and mental healthcare costs were estimated in ordinary least squares regression models in the second stage. Log predicted costs from the second stage were compared to determine the relative costs associated with each cohort.<bold>Results: </bold>Significant differences (p < 0.008) in total costs were found between the combination therapy (log predicted cost = 9.526) and psychotherapy cohorts (log predicted cost = 8.120) in the analysis that included all observations (n = 9110). In the analysis that included patients who initiated therapy with a non-mental health provider (n = 2673), the drug therapy cohort (log predicted cost = 8.238) was found to be significantly more costly as compared to the no therapy cohort (log predicted cost = 7.788).<bold>Conclusions: </bold>These results indicate that after controlling for both observed and unobserved factors, total healthcare costs may be higher in patients who initiate therapy with drug therapy and combination therapy as opposed to no therapy or psychotherapy. In addition, the finding that patients initially receiving psychotherapy alone tend to have higher mental healthcare costs but lower total healthcare costs than other patients may indicate that psychotherapy has an impact on comorbid illness and may subsequently reduce total healthcare costs. [ABSTRACT FROM AUTHOR]