| Variable | Cases No. (%) | Controls No. (%) | Total No. (%) | P-value* |
| Stressful life events | ||||
| Exposed | 32 (64) | 19 (38) | 51 (51) | 0.001 |
| Not exposed | 18 (36) | 31 (62) | 49 (49) | |
| Total | 50 (100) | 50 (100) | 100 (100) | |