Cognitive alterations in patients with non-affective psychotic disorder and their unaffected siblings and parents.
OBJECTIVE
The purpose of this study was to examine a range of cognitive measures as candidate phenotypic liability markers for psychosis in a uniquely large sample of patients with psychosis, their unaffected relatives and control subjects.


METHODS
Patients with non-affective psychosis (n = 1093), their unaffected siblings (n = 1044), parents (n = 911), and controls (n = 587) completed a comprehensive cognitive test battery. Cognitive functioning was compared using tests of verbal learning and memory, attention/vigilance, working memory, processing speed, reasoning and problem solving, acquired knowledge, and social cognition. Age- and gender-adjusted z-scores were compared between groups using mixed-model analyses of covariance. Clinically relevant impairment (-1 and -2 SD from control mean) was compared between subject groups.


RESULTS
Patients performed significantly worse than controls in all cognitive domains (z-range -0.26 to -1.34). Siblings and parents showed alterations for immediate verbal learning, processing speed, reasoning and problem solving, acquired knowledge, and working memory (z-range -0.22 to -0.98). Parents showed additional alterations for social cognition. Prevalence of clinically relevant impairment in relatives ranged from 50% (-1 SD criterion) to 10% (-2 SD criterion).


CONCLUSIONS
Cognitive functioning is a candidate intermediate phenotype given significant small to large alterations in patients and intermediate alterations in first-degree relatives.
Department of Psychiatry, Academic Medical Centre University of Amsterdam, The Netherlands.
J
J
Meijer
C J P
CJ
Simons
P J
PJ
Quee
K
K
Verweij
D000328:Adult; D001288:Attention; D003071:Cognition; D005192:Family Health / Q000706:statistics & numerical data; D005260:Female; D006801:Humans; D007361:Intelligence Tests; D008297:Male; D008570:Memory, Short-Term; D016743:Mental Competency; D008875:Middle Aged; D009426:Netherlands / Q000453:epidemiology; D009483:Neuropsychological Tests; D010290:Parents / Q000523:psychology*; D019989:Persons with Intellectual Disabilities / Q000706:statistics & numerical data; D015995:Prevalence; D011340:Problem Solving; D011597:Psychomotor Performance; D011618:Psychotic Disorders / Q000175:diagnosis / Q000453:epidemiology / Q000523:psychology; D035781:Siblings / Q000523:psychology*; D014706:Verbal Learning