Table 1.
Comparison of baseline sample characteristics between responders and nonresponders after six ketamine infusions.
| Variables | Total sample (n = 96) | Responder (n = 65) | Nonresponder (n = 31) | Statistics | ||
|---|---|---|---|---|---|---|
| N (%) | N (%) | N (%) | χ2 | df | p | |
| Female | 51 (53.1) | 35 (53.8) | 16 (51.6) | 0.04 | 1 | 0.84 |
| Employment | 39 (40.6) | 30 (46.2) | 9 (29.0) | 2.5 | 1 | 0.11 |
| Married | 51 (53.1) | 36 (55.4) | 15 (48.4) | 0.4 | 1 | 0.52 |
| TRD | 78 (81.3) | 53 (81.5) | 25 (80.6) | 0.01 | 1 | 0.92 |
| Depression | 0.06 | 1 | 0.81 | |||
| Unipolar | 76 (79.2) | 51 (67.1) | 25 (32.9) | |||
| Bipolar | 20 (20.8) | 14 (70.0) | 6 (30.0) | |||
| Mean (SD) | Mean (SD) | Mean (SD) | T/Z | df | p | |
| Age (years) | 34.4 (11.6) | 35.2 (11.1) | 33.0 (12.5) | 0.9 | 94 | 0.38 |
| Education (years) | 12.4 (3.3) | 12.8 (3.2) | 11.5 (3.4) | 1.8 | 94 | 0.07 |
| BMI (kg/m2) | 22.3 (3.6) | 22.5 (3.5) | 22.1 (3.7) | 0.4 | 94 | 0.68 |
| Duration of illness (months) | 101.8 (97.5) | 105.9 (100.9) | 93.0 (90.8) | —a | —a | 0.48 |
| Baseline MADRS scores | 31.8 (7.6) | 31.8 (7.6) | 31.9 (7.8) | −0.03 | 94 | 0.97 |
| Baseline plasma VEGF levels (ng/ml) | 36.7 (72.8) | 43.0 (84.6) | 23.3 (35.2) | —a | —a | 0.60 |
Bolded values are p < 0.05.
a
Mann–Whitney U test.
BMI, Body Mass Index; MADRS, the Montgomery-Åsberg Depression Rating Scale; SD, standard deviation; TRD, treatment-resistant depression; VEGF, vascular endothelial growth factor.