SELF-REPORTS OF DEPRESSION SEVERITY: SENSITIVITY OF THE PHQ-9 AND QIDS-SR-16 TO THE THERAPEUTIC EFFECTS OF TMS

Background: Measurement-based care improves outcomes in the treatment of MDD.The PHQ-9 and QIDS-SR are widely used assessment tools but have not been compared in sensitivity to the therapeutic effects of TMS.Methods: The PHQ-9 and QIDS-SR were administered to 1,044patients with MDD treated at a large TMS practice in Southern California.Patients scored 10 on both instruments at baseline and received at least 36 TMS sessions (Mn= 39.8, SD=7.3).On each scale response was defined as 50% reduction in scores and remission as a postTMS score 5.Results: Baseline symptom severity was greater on the PHQ-9 (Mn=18.9,SD=4.3) than QIDS-SR (Mn=17.9,SD=3.7), paired t (1043)=10.2,P<0.0001, r=0.70.At the end of the acute course, symptom severity was greater on the QIDS-SR (Mn=9.9SD=5.7) than PHQ-9 (Mn=9.1,SD=6.4), paired-t(1043)=7.8,P<0.0001, r=0.88.Consequently, the raw change in scores was greater with the PHQ-9 (Mn=9.8,SD=6.6) than the QIDS-SR (Mn=8.1,SD=5.8), paired t(1043)=14.2,P<0.0001, r=0.80.Similarly, the percent change in scores was higher with the PHQ-9 (Mn=51.5%,SD=33.0)than QIDS-SR (Mn=44.6%,SD=30.2),paired-t(1043) =11.6, P<0.0001, r=0.82.The remission rate was 10% greater on the PHQ-9 than QIDS-SR (36.1% vs. 26.6%),P<0.0001, and the nonresponse rate was greater on the QIDS-SR than the PHQ-9 (50.7% vs. 42.1%),P<0.0001.Conclusions: The PHQ-9 and QIDS-SR were highly correlated at baseline and following TMS.In the same large patient sample, the PHQ-9 yielded higher symptom scores at baseline and lower scores after treatment.Consequently, the PHQ-9 was substantially more sensitive to symptom change following TMS than the QIDS-SR.