Internal consistency of the questionnaires
| Questionnaire | Internal consistency (Cronbach’s α) | Internal consistency of subscales (Cronbach’s α) |
| NEO-FFI | Acceptable (0.7) | 0.6–0.9 |
| BSI | Excellent (>0.9) | 0.6–0.8 |
| PSC | Excellent (>0.9) | 0.6–0.8 |
| GPBS | Good (0.8) | 0.6–0.9 |
BSI, Brief Symptom Inventory; GPBS, Ghent Parental Behaviour Scale; NEO-FFI, NEO-Five Factor Inventory, PSC, Physical Symptom Checklist.