Do baseline WAIS-III subtests predict treatment outcomes for depressed inpatients receiving fluoxetine?

This study aimed to determine whether baseline WAIS-III subtests could be associated with treatment outcomes for patients with major depressive disorder (MDD) receiving a 6-week fluoxetine treatment. A total of 131 acutely ill MDD inpatients were enrolled to receive 20 mg of fluoxetine daily for 6 weeks. Eight WAIS-III subtests were administered at baseline. Symptom severity and functional impairment were assessed at baseline, and again at weeks 1, 2, 3, 4, and 6 using the 17-item Hamilton Depression Rating Scale (HAMD-17) and the Modified Work and Social Adjustment Scale (MWSAS), respectively. The generalized estimating equations method was used to analyze the influence of potential predictors over time on the HAMD-17 and MWSAS, after adjusting for covariates. Of the 131 participants, 104 (79.4%) who completed 8 WAIS-III subtests at baseline and had at least one post-baseline assessment were included in the analysis. Patients with lower forward digit span scores were more likely to have poor treatment outcomes, both measured by HAMD-17, and by MWSAS. Forward digit span may be clinically useful in identifying MDD patients with greater treatment difficulty in symptoms and functioning. Other neurocognitive tests to predict treatment outcome require further exploration.