Table 2.
Multiple Regression Statistics for Models Predicting Occipital GABA in Patients with Major Depressive Disorder
| β | Adjusted R2 | ΔR2 | |
|---|---|---|---|
| Step 1: All Models | .301 (p = .001) | .323 (p = .001) | |
| TRD vs. nTRD | −.57 (p =.001) | ||
| Step 2: Model 1 | .238 (p = .019) | .011 (p = 0.93) | |
| TRD vs. nTRD | −.59 (p = .003) | ||
| HRSD17 | −.09 (p = 0.72) | ||
| HAM-A | .14 (p = 0.57) | ||
| Comorbid anxiety disorder | −.06 (p = .73) | ||
| Step 2: Model 2 | .233 (p = .024) | .026 (p = 0.79) | |
| TRD vs. nTRD | −.60 (p = .001) | ||
| Non-hispanic Caucasian vs. any other ethnicity | .16 (p = 0.38) | ||
| HH-SES | .03 (p = 0.88) | ||
| Years of education | .05 (p = 0.84) | ||
| Step 2: Model 3 | .245 (p = .017) | .016 (p = 0.88) | |
| TRD vs. nTRD | −.58 (p = .001) | ||
| Age | .10 (p = 0.60) | ||
| Age of illness onset | −.14 (p = 0.44) | ||
| Single episode vs. recurrent | −.02 (p = 0.93) | ||
| Step 2: Model 4 | .274 (p = .006) | .019 (p = 0.66) | |
| TRD vs. nTRD | −.49 (p = .01) | ||
| 2-week washout vs. > 2-week washout | .05 (p = 0.81) | ||
| ADM-naïve vs. any exposure | −.14 (p = 0.42) | ||
Note: TRD = Treatment-Resistant Depression; nTRD = Non-Treatment-resistant Major Depressive Disorder; HRSD17 = Hamilton Rating Scale for Depression, 17-item; HAM-A = Hamilton Anxiety Rating Scale; HH-SES = Hollingshead Four-Factor Index of Social Position; ADM = antidepressant medication