title: High educational performance is a distinctive feature of bipolar disorder: a study on cognition in bipolar disorder, schizophrenia patients, relatives and controls.
abstract: BACKGROUND
  Schizophrenia is associated with lower intelligence and poor educational performance relative to the general population. This is, to a lesser degree, also found in first-degree relatives of schizophrenia patients. It is unclear whether bipolar disorder I (BD-I) patients and their relatives have similar lower intellectual and educational performance as that observed in schizophrenia.
  
  
  METHODS
  This cross-sectional study investigated intelligence and educational performance in two outpatient samples [494 BD-I patients, 952 schizophrenia spectrum (SCZ) patients], 2231 relatives of BD-I and SCZ patients, 1104 healthy controls and 100 control siblings. Mixed-effects and regression models were used to compare groups on intelligence and educational performance.
  
  
  RESULTS
  BD-I patients were more likely to have completed the highest level of education (odds ratio 1.88, 95% confidence interval 1.66-2.70) despite having a lower IQ compared to controls (β = -9.09, S.E. = 1.27, p < 0.001). In contrast, SCZ patients showed both a lower IQ (β = -15.31, S.E. = 0.86, p < 0.001) and lower educational levels compared to controls. Siblings of both patient groups had significantly lower IQ than control siblings, but did not differ on educational performance. IQ scores did not differ between BD-I parents and SCZ parents, but BD-I parents had completed higher educational levels.
  
  
  CONCLUSIONS
  Although BD-I patients had a lower IQ than controls, they were more likely to have completed the highest level of education. This contrasts with SCZ patients, who showed both intellectual and educational deficits compared to healthy controls. Since relatives of BD-I patients did not demonstrate superior educational performance, our data suggest that high educational performance may be a distinctive feature of bipolar disorder patients.
authors.affiliation: Department of Psychiatry,University Medical Center Utrecht,Brain Center Rudolf Magnus,Utrecht,The Netherlands.
authors.forename: A
authors.initials: A
authors.lastname: Vreeker
authors.affiliation: Department of Psychiatry,University Medical Center Utrecht,Brain Center Rudolf Magnus,Utrecht,The Netherlands.
authors.forename: M P M
authors.initials: MP
authors.lastname: Boks
authors.affiliation: Department of Psychiatry,University Medical Center Utrecht,Brain Center Rudolf Magnus,Utrecht,The Netherlands.
authors.forename: L
authors.initials: L
authors.lastname: Abramovic
authors.affiliation: Department of Psychiatry,University Medical Center Utrecht,Brain Center Rudolf Magnus,Utrecht,The Netherlands.
authors.forename: S
authors.initials: S
authors.lastname: Verkooijen
authors.affiliation: Department of Psychiatry,University Medical Center Utrecht,Brain Center Rudolf Magnus,Utrecht,The Netherlands.
authors.forename: A H
authors.initials: AH
authors.lastname: van Bergen
authors.affiliation: Department of Psychiatry,University Medical Center Utrecht,Brain Center Rudolf Magnus,Utrecht,The Netherlands.
authors.forename: M H J
authors.initials: MH
authors.lastname: Hillegers
authors.affiliation: Department of Mood Disorders,PsyQ,The Hague,The Netherlands.
authors.forename: A T
authors.initials: AT
authors.lastname: Spijker
authors.affiliation: Parnassia BAVO Group,The Hague,The Netherlands.
authors.forename: E
authors.initials: E
authors.lastname: Hoencamp
authors.affiliation: Altrecht Institute for Mental Health Care,Utrecht,The Netherlands.
authors.forename: E J
authors.initials: EJ
authors.lastname: Regeer
authors.affiliation: Department of Psychiatry,University of Groningen,University Medical Center Groningen,Groningen,The Netherlands.
authors.forename: R F
authors.initials: RF
authors.lastname: Riemersma-Van der Lek
authors.affiliation: Dimence Centre for Bipolar Disorders,Almelo,The Netherlands.
authors.forename: A W M M
authors.initials: AW
authors.lastname: Stevens
authors.affiliation: Mental Health Services,Noord Holland Noord,Alkmaar,The Netherlands.
authors.forename: P F J
authors.initials: PF
authors.lastname: Schulte
authors.affiliation: Reinier van Arkel Group,'s-Hertogenbosch,The Netherlands.
authors.forename: R
authors.initials: R
authors.lastname: Vonk
authors.affiliation: Delta Center for Mental Health Care,Rotterdam,The Netherlands.
authors.forename: R
authors.initials: R
authors.lastname: Hoekstra
authors.affiliation: Delta Center for Mental Health Care,Rotterdam,The Netherlands.
authors.forename: N J M
authors.initials: NJ
authors.lastname: van Beveren
authors.affiliation: Altrecht Institute for Mental Health Care,Utrecht,The Netherlands.
authors.forename: R W
authors.initials: RW
authors.lastname: Kupka
authors.affiliation: Department of Psychiatry,University Medical Center Utrecht,Brain Center Rudolf Magnus,Utrecht,The Netherlands.
authors.forename: R M
authors.initials: RM
authors.lastname: Brouwer
authors.affiliation: Semel Institute For Neuroscience and Human Behavior,University of California-Los Angeles,Los Angeles,California,USA.
authors.forename: C E
authors.initials: CE
authors.lastname: Bearden
authors.affiliation: Institute of Psychiatry,Psychology and Neuroscience,King's College London,London,UK.
authors.forename: J H
authors.initials: JH
authors.lastname: MacCabe
authors.affiliation: Department of Psychiatry,University Medical Center Utrecht,Brain Center Rudolf Magnus,Utrecht,The Netherlands.
authors.forename: R A
authors.initials: RA
authors.lastname: Ophoff
mesh_terms: D000124:Achievement; D000328:Adult; D000368:Aged; D001714:Bipolar Disorder / Q000523:psychology*; D016022:Case-Control Studies; D003071:Cognition; D003430:Cross-Sectional Studies; D004522:Educational Status; D005190:Family / Q000523:psychology*; D005260:Female; D006801:Humans; D007360:Intelligence; D007361:Intelligence Tests; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D012559:Schizophrenia; D012565:Schizophrenic Psychology; D055815:Young Adult
keywords: Bipolar disorder; IQ; cognition; educational performance; familial vulnerability; intelligence; schizophrenia