title: A population-based longitudinal study of childhood neurodevelopmental disorders, IQ and subsequent risk of psychotic experiences in adolescence.
abstract: BACKGROUND
  Schizophrenia has a neurodevelopmental component to its origin, and may share overlapping pathogenic mechanisms with childhood neurodevelopmental disorders (NDs). Nevertheless, longitudinal studies of psychotic outcomes among individuals with NDs are limited. We report a population-based prospective study of six common childhood NDs, subsequent neurocognitive performance and the risk of psychotic experiences (PEs) in early adolescence.
  
  
  METHODS
  PEs were assessed by semi-structured interviews at age 13 years. IQ and working memory were measured between ages 9 and 11 years. The presence of six NDs (autism spectrum, dyslexia, dyspraxia, dysgraphia, dysorthographia, dyscalculia) was determined from parent-completed questionnaires at age 9 years. Linear regression calculated the mean difference in cognitive scores between children with and without NDs. Associations between NDs and PEs were expressed as odds ratios (ORs) with 95% confidence intervals (CIs); effects of cognitive deficits were examined. Potential confounders included age, gender, father's social class, ethnicity and maternal education.
  
  
  RESULTS
  Out of 8220 children, 487 (5.9%) were reported to have NDs at age 9 years. Children with, compared with those without, NDs performed worse on all cognitive measures; the adjusted mean difference in total IQ was 6.84 (95% CI 5.00-8.69). The association between total IQ and NDs was linear (p < 0.0001). The risk of PEs was higher in those with, compared with those without, NDs; the adjusted OR for definite PEs was 1.76 (95% CI 1.11-2.79). IQ (but not working memory) deficit partly explained this association.
  
  
  CONCLUSIONS
  Higher risk of PEs in early adolescence among individuals with childhood ND is consistent with the neurodevelopmental hypothesis of schizophrenia.
authors: Department of Psychiatry,University of Cambridge,UK.
authors: G M
authors: GM
authors: Khandaker
authors: Department of Psychiatry,University of Cambridge,UK.
authors: J
authors: J
authors: Stochl
authors: Centre for Mental Health,Addiction and Suicide Research, School of Social and Community Medicine,University of Bristol,UK.
authors: S
authors: S
authors: Zammit
authors: Centre for Mental Health,Addiction and Suicide Research, School of Social and Community Medicine,University of Bristol,UK.
authors: G
authors: G
authors: Lewis
authors: Department of Psychiatry,University of Cambridge,UK.
authors: P B
authors: PB
authors: Jones
mesh_terms: D000293:Adolescent; D000381:Agraphia / Q000453:epidemiology; D001072:Apraxias / Q000453:epidemiology; D002648:Child; D002659:Child Development Disorders, Pervasive / Q000453:epidemiology*; D015897:Comorbidity; D060705:Dyscalculia / Q000453:epidemiology; D004410:Dyslexia / Q000453:epidemiology; D004739:England / Q000453:epidemiology; D005260:Female; D006801:Humans; D007360:Intelligence / Q000502:physiology*; D007859:Learning Disabilities / Q000453:epidemiology*; D008137:Longitudinal Studies; D008297:Male; D008570:Memory, Short-Term / Q000502:physiology; D011618:Psychotic Disorders / Q000453:epidemiology*; D012306:Risk