title: Evidence that environmental and genetic risks for psychotic disorder may operate by impacting on connections between core symptoms of perceptual alteration and delusional ideation.
abstract: BACKGROUND
  Relational models of psychopathology propose that symptoms are dynamically connected and hypothesize that genetic and environmental influences moderate the strength of these symptom connections. Previous findings suggest that the interplay between hallucinations and delusions may play a crucial role in the development of psychotic disorder. The current study examined whether the connection between hallucinations and delusions is impacted by proxy genetic and environmental risk factors.
  
  
  METHODS
  Hallucinations and delusions at baseline and at 3-year follow-up were assessed in a sample of 1054 healthy siblings and 918 parents of 1109 patients with psychosis, and in 589 healthy controls (no familial psychosis risk). Environmental factors assessed were cannabis use, childhood trauma, and urbanicity during childhood. Logistic regression analyses tested whether familial psychosis risk predicted increased risk of delusions, given presence of hallucinations. Moderating effects of environmental factors on the hallucination-delusion association were tested in a similar fashion, restricted to the control and sibling groups.
  
  
  RESULTS
  The risk of delusions, given hallucinations, was associated with proxy genetic risk: 53% in parents, 47% in siblings, and 36% in controls. The hallucination-delusion association was stronger in those reporting cannabis use (risk difference: 32%) and childhood trauma (risk difference: 15%) although not all associations were statistically conclusive (respectively: p = .037; p = .054). A directionally similar but nonsignificant effect was found for urb anicity during childhood (risk difference: 14%, p =.357).
  
  
  CONCLUSIONS
  The strength of the connection between delusions and hallucinations is associated with familial and environmental risks for psychotic disorder, suggesting that specific symptom connections in the early psychosis psychopathology network are informative of underlying mechanisms.
authors.affiliation: Department of Psychiatry and Psychology, South Limburg Mental Health Research and Teaching Network, EURON, Maastricht University Medical Centre, Maastricht, the Netherlands;
authors.forename: Feikje
authors.initials: F
authors.lastname: Smeets
authors.affiliation: Department of Psychiatry and Psychology, South Limburg Mental Health Research and Teaching Network, EURON, Maastricht University Medical Centre, Maastricht, the Netherlands;
authors.forename: Tineke
authors.initials: T
authors.lastname: Lataster
authors.affiliation: Department of Psychiatry and Psychology, South Limburg Mental Health Research and Teaching Network, EURON, Maastricht University Medical Centre, Maastricht, the Netherlands;
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Viechtbauer
authors.affiliation: Department of Psychiatry and Psychology, South Limburg Mental Health Research and Teaching Network, EURON, Maastricht University Medical Centre, Maastricht, the Netherlands;
authors.forename: Philippe
authors.initials: P
authors.lastname: Delespaul
mesh_terms: D000293:Adolescent; D000328:Adult; D000069586:Adult Survivors of Child Adverse Events / Q000706:statistics & numerical data; D001530:Belgium / Q000453:epidemiology; D003702:Delusions / Q000453:epidemiology / Q000209:etiology / Q000235:genetics*; D004777:Environment; D005260:Female; D020022:Genetic Predisposition to Disease; D006212:Hallucinations / Q000453:epidemiology / Q000209:etiology / Q000235:genetics*; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D002189:Marijuana Abuse / Q000453:epidemiology; D008875:Middle Aged; D009426:Netherlands / Q000453:epidemiology; D011618:Psychotic Disorders / Q000453:epidemiology / Q000209:etiology / Q000235:genetics*; D014505:Urban Population / Q000706:statistics & numerical data; D055815:Young Adult
keywords: delusions; hallucinations; psychosis