Table 2. Psychopathological, neurocognitive and demographic variables for DSM-IV diagnostic concordant, discordant and healthy MZ twin pairs.
| CONCORDANT (8 subjects, 8 female) |
DISCORDANT (12 subjects, 4 female) |
HEALTHY (14 subjects, 4 female) |
Group comparison | ||||
|---|---|---|---|---|---|---|---|
| Mean (SD) | Range | Mean (SD) | Range | Mean (SD) | Range | X-squareda; p | |
| Age | 42.5 (13) | 22–54 | 37 (10.9) | 20–50 | 30.3 (7.3) | 19–39 | 5.9; 0.052 |
| IQ | 105.1 (12.5) | 87–127 | 108.1 (11.8) | 87–131 | 110.5 (5.5) | 103–118 | 1.9; 0.393 |
| Current psycho-pathology (total BSI) | 27.9 (16.5) | 6–57 | 20.9 (13.3) | 4–45 | 10.6 (9.3) | 1–33 | 8.7; 0.013* |
| Current depressive symptoms (BSI subscale) | 6.9 (6.5) | 1–20 | 3.5 (2.7) | 0–9 | 1.7 (1.8) | 0–6 | 6.4; 0.04* |
Subjects from discordant twin pairs exhibit intermediate BSI scores (as compared with subjects from healthy or concordant groups) since they constitute a 50% of affected and a 50% of non-affected subjects (their individual scores being averaged).
Notes: SD, standard deviation; IQ, intellectual quotient; BSI, Brief Symptom Inventory
a, Kruskal-Wallis X-squared, as these variables were continuous
*, statistically significant p-value.