Table 1.
Sample characteristics.
| Nondepressed controls (n = 27) |
Major depressive disorder (n = 21) |
||
|---|---|---|---|
| Mdn (IQR) [Min, Max] /n (%) | Mdn (IQR) [Min, Max] /n (%) | Test statistics | |
| Age [years] | 28.0 (16.0) [20.0, 57.0] | 33.0 (27.0) [19.0, 59.0] | U = 567.5, p = .050 |
| Body Mass Index (BMI) | 23.0 (5.6) [18.6, 30.7] | 25.5 (5.4) [18.0, 34.6] | U = 571.5, p = .061 |
| Depressive symptom severity (BDI-II) | 2.0 (3.5) [0.0, 10.0] | 23.0 (6.0) [9.0, 51.0] | U = 379.5, p < .001 |
| Child maltreatment experiences (CTQ) | 29.0 (12.5) [25.0, 52.0] | 43.0 (17.0) [27.0, 58.0] | U = 509.0, p = .002 |
| Potentially traumatic life events (PDS) | 0 (2) [0, 10] | 2 (2) [0, 6] | U = 535.5, p = .007 |
| Posttraumatic distress (PDS) | 2 (5.5) [0, 13] | 9 (10.0) [0, 34] | U = 483.5, p < .001 |
| Mental and physical health | |||
| Antidepressant medication a | 0 (0%) | 12 (57.1%) | χ2 = 17.64, p < .001 |
| Previous depressive episodes | 0 (0) [0, 1] | 3 (3) [0, 11b] | U = 411.0, p < .001 |
| Concurrent comorbid mental health diagnosis c | 0 (0%) | 8 (38.1%) | χ2 = 9.75, p < .001 |
| Lifetime mental health diagnosis | 8d (29.6%) | 20e (95.2%) | χ2 = 8.73, p = .001 |
| Chronic physical illness f | 4 (14.8%) | 4 (19.0%) | χ2 = 0.00, p = .715 |
| Irregular or missing menstrual cycle | 3 (11.1%) | 7 (33.3%) | χ2 = 2.32, p = .081 |
| Hair-related variables | |||
| Sample weight [mg] | 10.1 (0.1) [9.7, 10.2] | 10.0 (0.1) [9.9, 10.2] | U = 697.0, p = .410 |
| Natural hair color g |
nred-blond = 12 (44.4%), nbrown-black = 15 (55.6%) |
nred-blond = 10 (50.0%), nbrown-black = 10 (50.0%) |
χ2 = 0.01, p = .773 |
| Weekly hair washings | 3.5 (1.0) [1.0, 7.0] | 3.0 (1.5) [1.5, 7.0] | U = 705.5, p = .351 |
| Hair dying g | 5 (19.2%) | 9 (42.9%) | χ2 = 2.07, p = .112 |
| Hair coloring | 3 (11.1%) | 4 (19.0%) | χ2 = 0.13, p = .683 |
Note: Group differences were analyzed with Mann-Whitney U-tests. Distributions of count data were compared using Fisher's exact test. a Patients with antidepressant medication received Bupropion, Escitalopram, Mirtazapine, Trimipramine, Fluoxetine, Venlafaxine, Duloxetine, and combinations thereof, respectively (i.e., Paroxetine/Escitalopram, Trimipramine/Escitalopram, Mirtazapine/Escitalopram, Venlafaxine/Pregabalin, and Pregabalin/Sertraline/Bupropion/Trazodone). b Two participants could not remember the exact number of previous MDD episodes; however, the number was higher then 10. c Eight MDD patients were also diagnosed with specific phobia (n = 3), social phobia (n = 2), binge eating disorder, and/or agoraphobia with and without panic disorder. d Lifetime diagnoses of nondepressed controls include depressive episodes (n = 3), adjustment disorder (n = 2), agoraphobia with and without panic disorder, and spider phobia (each n = 1). e In the MDD group, all lifetime diagnoses involved MDD (n = 20), including cases with remitted anxiety disorders (n = 11, i.e., specific or social phobia, panic disorder with agoraphobia), posttraumatic stress disorder (n = 4), and/or bulimia nervosa (n = 2). f Including n = 6 hypothyroidism with compensatory medication. g One missing value.