Table 1.
Sample characteristics: Demographic information and group comparisons
| No MDD (n = 61) | Remitted MDD (n = 55) | Current MDD (n = 101) | Healthy controls (n = 81) | Group comparisons | |
|---|---|---|---|---|---|
| Gender | 42 m | 30 m | 62 m | 41 m | χ2(3) = 5.47, |
| 19 f | 25 f | 39 f | 40 f | p = 0.140 | |
| Age, mean (s.d.) | 40.6 (14.6) | 37.5 (13) | 41.5 (14.8) | 40.3 (17) | F(3,293) = 0.83, p = 0.480 |
| IQ, mean (s.d.) | 98.2 (12.4) | 100.2 (10.8) | 98.5 (10.2) | 101 (12.4) | F(3,291) = 0.99, p = 0.397 |
| Education level | None: 6.8% | None: 0% | None: 4% | None: 0% | χ2(8) = 15.32, p = 0.083 |
| Low: 15.3% | Low: 11.3% | Low: 16.2% | Low: 7.4% | ||
| Middle: 44.1% | Middle: 37.7% | Middle: 42.4% | Middle: 40.7% | ||
| High: 33.9% | High: 50.9% | High: 37.4% | High: 51.9% | ||
| SWM errors, mean (s.d.) | 24.5 (20.5) | 19.1 (20.5) | 26.3 (20.9) | 23.5 (28.8) | F(3,289) = 1.13, p = 0.337 |
| Perseverative errors (s.d.) | 9 (6.7) | 10 (7.8) | 11 (8.2) | 10 (7.6) | F(3,285) = 0.71, p = 0.545 |
| Learning criterion reached | 68.9% | 65.5% | 65.3% | 65.4% | χ2(3) = 0.26, p = 0.968 |
| IDS-SR score, mean (s.d.) | 23.0 (14) | 28.1 (9.7) | 41.3 (11.8) | 4.9 (0.4) | F(3,290) = 182.4, p < 0.001 |
| No of diagnosesa | – | χ2(10) = 88.33, p < 0.001 | |||
| 0 | 19.7% | – | – | ||
| 1 | 49.2% | 14.5% | 12.9% | ||
| 2 | 27.9% | 49.1% | 36.6% | ||
| 3 | 3.3% | 29.1% | 29.7% | ||
| 4 | – | 7.3% | 14.9% | ||
| 5 | – | – | 5.9% |
IDS-SR, Inventory of Depressive Symptomatology – self-report version; SWM, spatial working memory; s.d., standard deviation.
a
Total number of diagnoses: the No MDD group included 12 individuals (19.7%) for whom the diagnosis was undefined, but there was a strong suspicion of ADHD and/or ASD at the time of inclusion. These are recorded as having zero diagnoses in the table.