Cognitive functioning of bipolar I patients and relatives from families with or without schizophrenia or schizoaffective disorder.
BACKGROUND
Bipolar I disorder patients show cognitive impairments, and genetic vulnerability to other psychotic disorders may modify these impairments. We set out to assess cognitive functions and estimate their heritability in bipolar I disorder patients (bipolar families) and unaffected relatives in a group of families with bipolar I disorder only and in another group of families with both bipolar I disorder and schizophrenia or schizoaffective disorder (mixed families).


METHODS
A neuropsychological test battery was administered to 20 bipolar patients and 36 relatives from bipolar families, 19 bipolar patients and 28 relatives from mixed families and 55 controls, all representing population-based samples.


RESULTS
Irrespective of the family group, patients and relatives were impaired in psychomotor processing speed. Both patient groups were impaired in executive functioning, but the deficit was more severe in patients from mixed families. Patients from bipolar families scored lower than controls in nearly all measures of verbal memory. All relatives were slightly impaired in executive functioning. The heritability of cognitive functions was generally similar irrespective of psychopathology in the family. However, there were greater genetic effects in several cognitive tasks in mixed families.


CONCLUSIONS
The small sample size and familial type of bipolar disorder could limit the generalizability of the results.


CONCLUSIONS
Impaired psychomotor processing speed and executive functions may represent markers of susceptibility to bipolar I disorder irrespective of psychopathology within the family. Generalized impairment in verbal memory, in turn, may associate more with bipolar disorder than to vulnerability to other psychotic disorders.
Antila
Mervi
M
Department of Mental Health and Alcohol Research, National Public Health Institute, Helsinki, Finland. mervi.antila@ktl.fi
Partonen
Timo
T
Kieseppä
Tuula
T
Suvisaari
Jaana
J
Eerola
Mervi
M
Lönnqvist
Jouko
J
Tuulio-Henriksson
Annamari
A
D000328:Adult; D001714:Bipolar Disorder / Q000175:diagnosis / Q000453:epidemiology* / Q000235:genetics*; D003071:Cognition; D039721:Diagnostic and Statistical Manual of Mental Disorders; D005190:Family / Q000523:psychology; D005260:Female; D006801:Humans; D008297:Male; D008568:Memory; D008875:Middle Aged; D009483:Neuropsychological Tests; D010641:Phenotype; D011597:Psychomotor Performance; D011618:Psychotic Disorders / Q000175:diagnosis / Q000453:epidemiology*; D012559:Schizophrenia / Q000175:diagnosis / Q000453:epidemiology*; D014706:Verbal Learning