Project among African-Americans to explore risks for schizophrenia (PAARTNERS): evidence for impairment and heritability of neurocognitive functioning in families of schizophrenia patients.
OBJECTIVE
Neurocognitive impairments in schizophrenia are well replicated and widely regarded as candidate endophenotypes that may facilitate understanding of schizophrenia genetics and pathophysiology. The Project Among African-Americans to Explore Risks for Schizophrenia (PAARTNERS) aims to identify genes underlying liability to schizophrenia. The unprecedented size of its study group (N=1,872), made possible through use of a computerized neurocognitive battery, can help further investigation of the genetics of neurocognition. The current analysis evaluated two characteristics not fully addressed in prior research: 1) heritability of neurocognition in African American families and 2) relationship between neurocognition and psychopathology in families of African American probands with schizophrenia or schizoaffective disorder.


METHODS
Across eight data collection sites, patients with schizophrenia or schizoaffective disorder (N=610), their biological relatives (N=928), and community comparison subjects (N=334) completed a standardized diagnostic evaluation and the computerized neurocognitive battery. Performance accuracy and response time (speed) were measured separately for 10 neurocognitive domains.


RESULTS
The patients with schizophrenia or schizoaffective disorder exhibited less accuracy and speed in most neurocognitive domains than their relatives both with and without other psychiatric disorders, who in turn were more impaired than comparison subjects in most domains. Estimated trait heritability after inclusion of the mean effect of diagnostic status, age, and sex revealed significant heritabilities for most neurocognitive domains, with the highest for accuracy of abstraction/flexibility, verbal memory, face memory, spatial processing, and emotion processing and for speed of attention.


CONCLUSIONS
Neurocognitive functions in African American families are heritable and associated with schizophrenia. They show potential for gene-mapping studies.
Calkins
Monica E
ME
Department of Psychiatry, University of Pennsylvania, Philadelphia, PA 19104, USA. mcalkins@upenn.edu
Tepper
Ping
P
Gur
Ruben C
RC
Ragland
J Daniel
JD
Klei
Lambertus
L
Wiener
Howard W
HW
Richard
Jan
J
Savage
Robert M
RM
Allen
Trina B
TB
O'Jile
Judith
J
Devlin
Bernie
B
Kwentus
Joseph
J
Aliyu
Muktar H
MH
Bradford
L Dianne
LD
Edwards
Neil
N
Lyons
Paul D
PD
Nimgaonkar
Vishwajit L
VL
Santos
Alberto B
AB
Go
Rodney C P
RC
Gur
Raquel E
RE
D000328:Adult; D001741:Black or African American; D001714:Bipolar Disorder / Q000208:ethnology; D001921:Brain / Q000503:physiopathology*; D002874:Chromosome Mapping; D003072:Cognition Disorders / Q000208:ethnology / Q000235:genetics / Q000503:physiopathology; D003865:Major Depressive Disorder / Q000208:ethnology; D005260:Female; D020022:Genetic Predisposition to Disease; D006801:Humans; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D015995:Prevalence; D011618:Psychotic Disorders / Q000208:ethnology; D011930:Reaction Time; D012307:Risk Factors; D012559:Schizophrenia / Q000208:ethnology*; D012720:Severity of Illness Index; D019966:Substance-Related Disorders / Q000208:ethnology