Evidence that self-reported psychotic experiences represent the transitory developmental expression of genetic liability to psychosis in the general population
✍ Scribed by Tineke Lataster; Inez Myin-Germeys; Catherine Derom; Evert Thiery; Jim van Os
- Publisher
- John Wiley and Sons
- Year
- 2009
- Tongue
- English
- Weight
- 171 KB
- Volume
- 150B
- Category
- Article
- ISSN
- 1552-4841
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✦ Synopsis
Abstract
It has been suggested that self‐reported, common, non‐clinical psychotic experiences may represent the transitory developmental expression of distributed genetic risk for psychosis. In a sample of female MZ (176 pairs) and DZ twins (113 pairs), cross‐twin, cross‐trait analyses were conducted to investigate the association between repeated continuous measures of self‐reported psychotic experiences (PE—three measures over 18 months), assessed with the CAPE, in one twin and clinical interview categorical measures of psychotic symptoms (PS), assessed with SCID‐I, in the other twin. The results showed that in MZ but not DZ pairs (interaction: χ^2^ = 7.9, df = 1, P = 0.005), the cross‐twin association between PE and PS was large and significant (standardized effect size: 0.26, 95% CI: 0.10–0.42) and of similar magnitude as the within‐twin PE–PS association (standardized effect size: 0.28, 95% CI: 0.10–0.45), demonstrating both PE validity and genetic effects. In addition, the cross‐twin association between PE and PS was significantly larger (interaction: χ^2^ = 20.3, df = 1, P < 0.0001) for younger MZ twins (standardized effect size: 0.67, 95% CI: 0.44–0.90) than older MZ twins (standardized effect size: −0.05, 95% CI: −0.26 to 0.16), demonstrating developmental effects. This study indicates that self‐reported psychotic experiences in the general population may represent the developmental expression of population genetic risk for psychosis. © 2009 Wiley‐Liss, Inc.