Table 1.
Sample characteristics
| School performance sample (n = 2,362) | IQ sample (n = 3,737) | |||
|---|---|---|---|---|
| n | n | |||
| Child characteristics | ||||
| Sex, % girls | 2,362 | 52.6% | 3,737 | 51.5% |
| Ethnicity, % | 2,350 | 3,716 | ||
| Dutch | 70.8% | 66.8% | ||
| Other Western | 8.5% | 8.6% | ||
| Non‐Western | 20.6% | 24.6% | ||
| Auditory hallucinations, % | 2,362 | 3,737 | ||
| No | 74.2% | 73.9% | ||
| A bit | 20.4% | 19.7% | ||
| Clearly | 5.4% | 6.4% | ||
| Visual hallucinations, % | 2,362 | 3,737 | ||
| No | 84.1% | 83.4% | ||
| A bit | 12.8% | 12.9% | ||
| Clearly | 3.1% | 3.7% | ||
| Age at PEs assessment, mean (SD) | 2,362 | 9.8 (0.3) | 3,737 | 9.8 (0.4) |
| PEs assessment, % filled out alone | 2,362 | 48.1% | 3,736 | 44.3% |
| CITO test score, median (IQR), range (501–550) | 2,362 | 541.0 (13.0) | 2,066 | 541.0 (13.0) |
| Age at CITO test assessment, mean (SD) | 2,119 | 11.8 (0.4) | 1,983 | 11.9 (0.4) |
| Nonverbal IQ, mean (SD) | 2,066 | 105.2 (14.2) | 3,737 | 103.3 (14.5) |
| Age at IQ assessment, mean (SD) | 2,222 | 6.1 (0.4) | 3,737 | 6.0 (0.4) |
| Maternal characteristics | ||||
| Educational level, % | 2,215 | 3,511 | ||
| High | 67.5% | 62.9% | ||
| Medium | 30.6% | 35.1% | ||
| Low | 1.9% | 2.0% | ||
| Nonverbal IQ, median (IQR) | 2,177 | 100.0 (17.0) | 3,629 | 100.0 (17.0) |
PEs, psychotic experiences. School performance and IQ sample are overlapping (n = 2,066).