title: Cognitive functioning in patients with familial bipolar I disorder and their unaffected relatives.
abstract: BACKGROUND
  Impairments in verbal learning and memory, executive functions and attention are manifest in some euthymic patients with bipolar disorder (BPD). However, evidence is sparse on their putative role as aetiologically important genetic vulnerability markers for the disorder. This population-based study examined the cognitive functions of affected and unaffected individuals in families with BPD. The aim was to discover whether any cognitive function would indicate genetic liability to the disorder and could thus be regarded as endophenotypes of BPD.
  
  
  METHODS
  A diagnostic interview and a neuropsychological test battery were administered to 32 familial bipolar I disorder patients, 40 of their unaffected first-degree relatives and 55 controls, all representing population-based samples.
  
  
  RESULTS
  Unaffected first-degree relatives showed impairment in psychomotor performance speed and slight impairment in executive function. Bipolar patients were impaired in verbal learning and memory compared with unaffected relatives and controls. They also differed from controls in tasks of executive functions. There were no difference between the groups in simple attention and working memory tasks.
  
  
  CONCLUSIONS
  Impaired psychomotor performance speed and executive function may represent endophenotypes of BPD, reflecting possible underlying vulnerability to the disorder. Verbal memory impairments appear to be more related to the fully developed disorder.
authors.affiliation: Department of Mental Health and Alcohol Research, National Public Health Institute, Helsinki, Finland. mervi.antila@ktl.fi
authors.forename: Mervi
authors.initials: M
authors.lastname: Antila
authors.forename: Annamari
authors.initials: A
authors.lastname: Tuulio-Henriksson
authors.forename: Tuula
authors.initials: T
authors.lastname: Kieseppä
authors.forename: Mervi
authors.initials: M
authors.lastname: Eerola
authors.forename: Timo
authors.initials: T
authors.lastname: Partonen
authors.forename: Jouko
authors.initials: J
authors.lastname: Lönnqvist
mesh_terms: D001714:Bipolar Disorder / Q000175:diagnosis / Q000453:epidemiology* / Q000235:genetics*; D003072:Cognition Disorders / Q000175:diagnosis / Q000453:epidemiology*; D039721:Diagnostic and Statistical Manual of Mental Disorders; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D010641:Phenotype; D015995:Prevalence; D011596:Psychomotor Disorders / Q000175:diagnosis / Q000453:epidemiology; D012720:Severity of Illness Index