title: Young offspring at genetic risk of adult psychoses: the form of the trajectory of IQ or memory may orient to the right dysfunction at the right time.
abstract: OBJECTIVE
  Neurocognitive dysfunctions analogous to those of adult patients have been detected in children at risk of schizophrenia and bipolar disorder. This led to the following developmental question: Do IQ and memory impairments exhibit different developmental courses from childhood to young adulthood in terms of stability or fluctuations?
  
  
  METHODS
  In a high risk sample, we used a step by step sampling approach to narrow-down the early disease mechanisms. Upstream, we started with a 20-year follow-up of 48 densely affected multigenerational kindreds, including 1500 clinically characterized adult members. We then identified 400 adult members affected by a DSM-IV schizophrenia or bipolar disorder. Downstream, we finally focused on 65 offspring (of an affected parent) aged 7 to 22, who were administered a neuropsychological battery. We then constructed cross-sectional trajectories that were compared to those of controls.
  
  
  RESULTS
  The childhood IQ deficit displayed a stability until young adulthood. The delay in visual memory exhibited a non-linear two-stage trajectory: a lagging period during childhood followed by a recuperation period from adolescence until adulthood, as supported by a significant Group x Age Periods interaction. No data suggested deterioration between 7 and 22.
  
  
  CONCLUSIONS
  In these offspring at genetic risk, the developmental trajectory of global IQ impairment may not apply to specific domains of cognition such as episodic memory. Different cognitive dysfunctions would mark different developmental courses. The shape of the trajectories might itself have a meaning and provide empirical leads for targeting the right dysfunction at the right time in future prevention research.
authors.affiliation: Laval University and Centre de Recherche Université Laval Robert-Giffard, Laval, Québec, Canada. michel.maziade@psa.ulaval.ca
authors.forename: Michel
authors.initials: M
authors.lastname: Maziade
authors.forename: Nancie
authors.initials: N
authors.lastname: Rouleau
authors.forename: Caroline
authors.initials: C
authors.lastname: Cellard
authors.forename: Marco
authors.initials: M
authors.lastname: Battaglia
authors.forename: Thomas
authors.initials: T
authors.lastname: Paccalet
authors.forename: Isabel
authors.initials: I
authors.lastname: Moreau
authors.forename: Valérie
authors.initials: V
authors.lastname: Gagnon
authors.forename: Nathalie
authors.initials: N
authors.lastname: Gingras
authors.forename: Cecilia
authors.initials: C
authors.lastname: Marino
authors.forename: Elsa
authors.initials: E
authors.lastname: Gilbert
authors.forename: Marc-André
authors.initials: MA
authors.lastname: Roy
authors.forename: Chantal
authors.initials: C
authors.lastname: Mérette
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D015331:Cohort Studies; D005192:Family Health; D020022:Genetic Predisposition to Disease; D006801:Humans; D007361:Intelligence Tests; D008568:Memory; D008569:Memory Disorders / Q000175:diagnosis; D010290:Parents; D011618:Psychotic Disorders / Q000175:diagnosis* / Q000235:genetics*; D012306:Risk; D012923:Social Class