Table 1.
Characteristics of study population (N = 708)
| Age (years), mean (SD, range) | 17.8 (3.4,15–34) |
| Gender, n (%) | |
| Men | 294 (41.5) |
| Women | 414 (58.5) |
| Gender combination of twin pairs, n (%) | |
| Same sex female DZ | 134 (18.9) |
| Same sex female MZ | 158 (22.3) |
| Same sex female missing zygosity | 14 (2.0) |
| Same sex male DZ | 76 (10.7) |
| Same sex male MZ | 98 (13.8) |
| Same sex male missing zygosity | 12 (1.7) |
| Opposite-sex | 216 (30.5) |
| Level of education, n (%) | |
| Elementary school | 1 (0.1) |
| Intermediary vocational education | 88 (12.4) |
| High school | 379 (53.5) |
| Bachelor’s degree | 99 (14.0) |
| Master’s degree | 81 (11.4) |
| Missing | 60 (8.5) |
| Employment status, n (%) | |
| Homemaker | 2 (0.3) |
| Student | 603 (85.2) |
| Employed | 56 (7.9) |
| Missing | 48 (6.8) |
| Zygosity, n (%) | |
| MZ | 256 (36.2) |
| DZ | 426 (60.2) |
| Missing | 26 (3.7) |
| Outcome measures, mean (SD) | |
| Change in implicit self-esteem | − .145 (.451) |
| Change in positive affect | − 17.9 (40.0) |
| Change in negative affect | 22.0 (48.0) |
| Predictor measures, mean (SD) | |
| Birth weight in g | 2498 (501.8) |
| Gestational age in weeks | 36.4 (2.0) |
| Childhood trauma | 34.3 (9.0) |
| Severity of bullying | 9.9 (4.4) |
| Frequency of bullying | 10.7 (3.5) |
| Subjective social status | 38.3 (27.9) |
n indicates the number of individual twins, MZ monozygotic, DZ dizygotic