IQ and non-clinical psychotic symptoms in 12-year-olds: results from the ALSPAC birth cohort
Jeremy P. Horwood, Giovanni E. Salvi, Kate Thomas, Larisa Duffy, David Gunnell, Chris P. Hollis, Glyn Lewis, Paulo Rossi Menezes, Andrew David Thompson, Dieter Wolke, Stanley Zammit, Glynn L. Harrison
The British Journal of Psychiatry August 31, 2008 DOI: 10.1192/bjp.bp.108.051904 (opens in new tab)
Study at a glance
AI-extracted from the abstract| Characteristics | Longitudinal observational cohort study Peer reviewed |
|---|---|
| Sample size | 6,455 |
| Population | 12-year-old children in the Avon Longitudinal Study of Parents and Children (ALSPAC) birth cohort |
| Citations | 277 |
| Key findings | The 6-month prevalence of one or more psychosis-like symptoms was 13.7% (95% CI 12.8-14.5). After adjustment for confounders, the association between IQ and these symptoms was non-linear: only children with below-average IQ had an increased risk, with a weaker association also at high IQ. The authors conclude this pattern differs from the low-IQ association observed in schizophrenia. |
Abstract
Background: Non-clinical psychotic symptoms appear common in children, but it is possible that a proportion of reported symptoms result from misinterpretation. There is a well-established association between pre-morbid low IQ score and schizophrenia. Psychosis-like symptoms in children may also be a risk factor for psychotic disorder but their relationship with IQ is unclear.
Aims: To investigate the prevalence, nature and frequency of psychosis-like symptoms in 12-year-old children and study their relationship with IQ.
Method: Longitudinal study using the Avon Longitudinal Study of Parents and Children (ALSPAC) birth cohort. A total of 6455 children completed screening questions for 12 psychotic symptoms followed by a semi-structured clinical assessment. IQ was assessed at 8 years of age using the Wechsler Intelligence Scale for Children (3rd UK edition).
Results: The 6-month period prevalence for one or more symptoms was 13.7% (95% CI 12.8-14.5). After adjustment for confounding variables, there was a non-linear association between IQ score and psychosis-like symptoms, such that only those with below average IQ score had an increased risk of reporting such symptoms.
Conclusions: Non-clinical psychotic symptoms occur in a significant proportion of 12-year-olds. Symptoms are associated with low IQ and also less strongly with a high IQ score. The pattern of association with IQ differs from that observed in schizophrenia.
Citations in the library
Cited by 4
- Psychotic symptoms in the general population – an evolutionary perspective The British Journal of Psychiatry August 31, 2010
- Childhood sleep disturbance and risk of psychotic experiences at 18: UK birth cohort The British Journal of Psychiatry May 8, 2015
- Psychotic-Like Experiences: A Challenge in Definition and Assessment. Frontiers in Psychiatry March 29, 2021
- Childhood parasomnias and psychotic experiences at age 12 years in a United Kingdom birth cohort. Sleep March 1, 2014