Table 1.
Demographic Characteristics of Control and Sibling Groups
| Variable with M ± SD or n (%) | Control | Siblings | ||
|---|---|---|---|---|
| Male (n = 255) | Female (n = 304) | Male (n = 361) | Female (n = 431) | |
| Age at baseline (years) | 29.1 ± 10.3 | 31.0 ± 10.3 | 27.5 ± 7.7 | 28.0 ± 7.8 |
| WAIS-III IQ | 110.6 ± 15.4 | 108.6 ± 15.1 | 105.6 ± 16.1 | 100.8 ± 15.2 |
| Educational achievementa | 5.11 ± 1.82 | 5.67 ± 1.71 | 5.08 ± 2.12 | 5.22 ± 2.08 |
| Living alone | 61 (23.9) | 57 (18.8) | 80 (22.2) | 76 (17.6) |
| Married/living together | 83 (32.5) | 139 (45.7) | 128 (35.5) | 192 (44.5) |
| Ethnicity | ||||
| White | 226 (89.7) | 279 (93.6) | 313 (86.7) | 350 (81.2) |
| Moroccan | 5 (2.0) | — | 5 (1.4) | 13 (3.0) |
| Turkish | — | — | 5 (1.4) | 7 (1.6) |
| Surinamese or Caribbean | 1 (0.4) | 3 (1.0) | 8 (2.2) | 5 (1.2) |
| Asian | — | — | — | 2 (0.5) |
| Other, mixed or unknown | 20 (7.9) | 16 (5.4) | 30 (8.3) | 53 (12.3) |
| CAPE frequency scores | ||||
| Positive | 3.90 ± 3.35 | 3.75 ± 3.69 | 3.76 ± 3.58 | 4.11 ± 4.41 |
| Negative | 6.76 ± 4.55 | 6.75 ± 4.43 | 7.51 ± 5.07 | 8.00 ± 6.01 |
| Depression | 3.94 ± 2.53 | 5.24 ± 2.83 | 4.26 ± 2.82 | 5.68 ± 3.46 |
Note: CAPE, Community Assessment of Psychic Experiences; WAIS-III, Wechsler Adult Intelligence Scale, 3rd ed.
aTreated as an ordinal variable where 0 = no education, 1 = primary, 2 = lower secondary, 3 = higher secondary, 4 = lower high school, 5 = higher high school, 6 = lower vocational, 7 = higher vocational, 8 = university.