Pharmacotherapy guideline concordance for major depressive disorder and its link to functioning via symptom change

TL;DR

Following depression treatment guidelines improves patient functioning mainly by reducing symptoms over time.

Contribution

Shows guideline adherence improves functioning via symptom reduction in MDD patients.

Findings

Higher guideline concordance linked to 0.48-point disability score reduction.

Symptom severity change significantly mediated the effect on functioning.

Direct effect of guidelines independent of symptoms was not significant.

Abstract

Alleviation of symptom severity for major depressive disorder (MDD) is known to be associated with a lagged improvement of functioning. Pharmacotherapy guidelines support algorithms for MDD treatment. However, it is currently unclear whether concordance with guidelines influences functional recovery. A guideline concordance algorithm (GCA-8) was used to measure this pathway in a naturalistic clinical setting.

Data from 1403 adults (67% female, 84% non-Hispanic/Latino White, mean age of 43 years) with nonpsychotic MDD from the Penn State Psychiatry Clinical Assessment and Rating Evaluation System registry (visits from 02/01/2015 to 04/13/2021) were evaluated. Multivariable linear regression measured associations between GCA-8 and World Health Organization Disability Assessment Schedule 2.0 (WHODAS) scores. Mediation by MDD symptom severity using the Patient Health Questionnaire depression module (PHQ-9) was also evaluated.

This study found a statistically significant improvement in WHODAS scores (functioning) between baseline and final measures (−2 points, P < .001) within one year. A one standard deviation increase in the GCA-8 score was associated with a 0.48-point reduction in mean disability score (total effect; P = .02) with significant mediation by the change in MDD symptom severity (coefficient = −0.51, P < .001) and a nonsignificant natural direct effect of the GCA-8 independent of PHQ-9 change (coefficient = −0.02, P = .92).

Higher pharmacotherapy guideline concordance is associated with better functioning for MDD patients; this association likely occurs through improvement in MDD symptom severity rather than directly.

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