Demographic, clinical and neurocognitive characteristics of study participants*
| Characteristic | Healthy controls | Patients without TRD | Patients with TRD | ANOVA, F/χ2 | p value (ANOVA) | LSD | p value (Kruskal–Wallis test) |
|---|---|---|---|---|---|---|---|
| Age, yr | 65.6 ± 7.7 | 65.3 ± 8.5 | 66.5 ± 6.0 | 0.179 | 0.8 | – | – |
| No. (%) female | 21 (77.8) | 21 (77.8) | 22 (81.5) | 0.149 | 0.9 | – | – |
| Duration, yr | – | 12.2 ± 9.7 | 15.8 ± 14.3 | 1.152 | 0.3 | – | – |
| HDRS-17 score | 1.3 ± 1.7 | 7.0 ± 5.7 | 21.1 ± 9.5 | 67.208 | < 0.001 | Healthy controls < patients without TRD < patients with TRD | < 0.001 |
| Finger tapping (times) | 26.0 ± 6.5 | 23.7 ± 6.9 | 20.7 ± 9.2 | 3.144 | 0.05 | Healthy controls > patients with TRD | – |
| Verbal fluency (word counts) | 3.8 ± 2.1 | 3.1 ± 2.0 | 2.7 ± 2.0 | 2.050 | 0.1 | – | – |
| Dual task (word counts) | 4.2 ± 2.4 | 3.0 ± 1.9 | 2.9 ± 1.9 | 2.940 | 0.06 | Healthy controls > patients with TRD | – |
| WCST, % error | 47.38 ± 20.58 | 47.40 ± 17.90 | 57.56 ± 21.63 | 2.287 | 0.1 | – | – |
| WCST, % conceptual level | 37.35 ± 26.40 | 38.48 ± 23.58 | 27.22 ± 25.97 | 1.610 | 0.2 | – | – |
| WCST, category completed | 2.27 ± 2.38 | 2.93 ± 2.09 | 1.48 ± 2.01 | 3.023 | 0.05 | – | – |
ANOVA = analysis of variance; HDRS-17 = Hamilton Depression Rating Scale (17 items); LSD = least significant difference; TRD = treatment-resistant depression; WCST = Wisconsin Card Sorting Test.
↵* All data are given as means ± SDs unless specified otherwise.