The effect of short-term use of benzodiazepines on cognitive function of major depressive disorder patients being treated with antidepressants

Background: This study aimed to evaluate the effect of short-term use of benzodiazepines (BZDs) on cognitive function of major depressive disorder (MDD) patients being treated with antidepressants (ADs).

Methods: This was a part of a multi-center, multi-stage and prospective study of "Objective Diagnostic Indicators and Individualized Drug Intervention of Major Depressive Disorder (OIMDD)". Three hundred and fifty-three patients treated with the selective serotonin reuptake inhibitors (SSRIs) alone (Group 1) and 49 patients treated with SSRIs combined with short-term use of BZDs (Group 2) during the acute treatment period were included in the analysis. Cognitive function and depressive and anxiety symptoms were assessed at baseline, weekend 8 and 48. A cognitive test battery included 5 domains: information processing speed assessed by the Animal Verbal Fluency Scale (AVFS), Digit Symbol Coding Test (DSCT) and Color Trial Test (CTT), verbal learning assessed by the Hopkins Verbal Learning Test-Revised (HVLT-R), visual learning assessed by the Brief Visual Memory Test-Revised (BVMT-R), executive function assessed by the Stroop Color Word Test (SCWT), and attention or vigilance assessed by the Continuous Performance Test (CPT).

Results: Significant differences were found in education level (χ² = 5.442, p = 0.020), the severity of depressive (t = -1.982, p = 0.048) and anxiety symptoms (t = -2.629, p = 0.009) between Group 1 and 2 at baseline. There were no significant differences between G1 and G2 in cognitive functions at baseline. After Multiple correction, DSCT was better in patients treated with BZDs combined with ADs than in patients with ADs alone at weekend 8 without controlling education level, depressive and anxiety symptoms at baseline (F = -2.747, p = 0.042). After controlling these factors at baseline, the DSCT was still slightly high in patients treated with ADs combined with BZDs than in patients with ADs alone at weekend 8 (OR = 1.052, 95%CI:1.000-1.105). The repeated measurement analysis of variance showed that the DSCT could be improved by the treatment of BZDs combined with ADs at 1-year follow-up compared to baseline (F = 7.569, p = 0.006).

Conclusions: The findings suggest that short-term use of BZDs does not impair cognitive function of MDD patients; conversely, it could improve the information processing speed after acute treatment and at 1 year follow up.