Comparison of the Patient Health Questionnaire-9 and Quick Inventory of Depressive Symptomatology-Self Report in assessing the antidepressant effects of Transcranial Magnetic Stimulation: Sensitivity to change

Abstract

BackgroundThe PHQ-9 and QIDS-SR are widely used assessment tools but have not been compared in sensitivity to the antidepressant effects of TMS. MethodsThe PHQ-9 and QIDS-SR were administered to 578 patients with MDD treated at a large TMS practice in Southern California. At baseline patients scored ≥10 on both instruments and received ≥36 TMS sessions (Mn= 38.9, SD=5.3). Response was defined on each scale as ≥50% reduction in scores and remission as a post-TMS score ≤5. ResultsBaseline symptom severity was greater on the PHQ-9 (Mn=19.1, SD=4.2) than QIDS-SR (Mn=18.2, SD=3.7), P<0.0001. Both the change in scores from baseline to post-TMS [PHQ-9 (Mn=10.1, SD=6.8); QIDS-SR (Mn=8.4, SD=5.9), P<0.0001] and percent change [PHQ-9 (Mn=52.1%, SD=33.5); QIDS-SR (Mn=45.4%, SD=30.2), P<0.0001] were greater for the PHQ-9 than the QIDS. The remission rate was 10% greater with the PHQ-9 than QIDS-SR (37.5% vs. 27.9%), P<0.0001, while the nonresponse rate was greater on the QIDS-SR (49.7% vs. 42.9%), P<0.0001. Effect sizes for differences in effectiveness among 3 TMS protocols were greater for the PHQ-9 than QIDS-SR. The PHQ-9 also showed greater internal consistency and higher loadings on a single depression severity factor. LimitationsThese are real world data, and the order of scale administration was unconstrained. ConclusionsThe PHQ-9 and QIDS-SR were highly correlated at baseline and following TMS. Nonetheless, the PHQ-9 was more sensitive to symptom change and appeared to assess more consistently a single dimension of depression severity.