Predicting schizophrenia patients' real-world behavior with specific neuropsychological and functional capacity measures.
BACKGROUND
Significant neuropsychological (NP) and functional deficits are found in most schizophrenia patients. Previous studies have left questions as to whether global NP impairment or discrete domains affect functional outcomes, and none have addressed distinctions within and between ability and performance domains. This study examined the different predictive relationships between NP domains, functional competence, social competence, symptoms, and real-world behavior in domains of work skills, interpersonal relationships, and community activities.


METHODS
Two hundred twenty-two schizophrenic outpatients were tested with an NP battery and performance-based measures of functional and social competence and rated for positive, negative, and depressive symptoms. Case managers generated ratings of three functional disability domains.


RESULTS
Four cognitive factors were derived from factor analysis. Path analyses revealed both direct and mediated effects of NP on real-world outcomes. All NP domains predicted functional competence, but only processing speed and attention/working memory predicted social competence. Both competence measures mediated the effects of NP on community activities and work skills, but only social competence predicted interpersonal behaviors. The attention/working memory domain was directly related to work skills, executive functions had a direct effect on interpersonal behaviors, and processing speed had direct effects on all three real-world behaviors. Symptoms were directly related to outcomes, with fewer relationships with competence.


CONCLUSIONS
Differential predictors of functional competence and performance were found from discrete NP domains. Separating competence and performance provides a more precise perspective on correlates of disability. Changes in specific NP or functional skills might improve specific outcomes, rather than promoting global functional improvement.
Bowie
Christopher R
CR
Department of Psychiatry, Mount Sinai School of Medicine, New York, NY 10029, USA. christopher.bowie@mssm.edu
Leung
Winnie W
WW
Reichenberg
Abraham
A
McClure
Margaret M
MM
Patterson
Thomas L
TL
Heaton
Robert K
RK
Harvey
Philip D
PD
D000203:Activities of Daily Living / Q000523:psychology*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019090:Case Management; D003072:Cognition Disorders / Q000175:diagnosis* / Q000523:psychology / Q000534:rehabilitation; D032882:Comprehension; D004185:Disability Evaluation; D005260:Female; D006801:Humans; D008297:Male; D008609:Mental Status Schedule / Q000706:statistics & numerical data; D008875:Middle Aged; D009483:Neuropsychological Tests / Q000706:statistics & numerical data*; D015588:Observer Variation; D011340:Problem Solving; D011569:Psychiatric Status Rating Scales; D011594:Psychometrics / Q000706:statistics & numerical data; D011618:Psychotic Disorders / Q000175:diagnosis* / Q000523:psychology / Q000534:rehabilitation; D015203:Reproducibility of Results; D012559:Schizophrenia / Q000175:diagnosis* / Q000534:rehabilitation; D012565:Schizophrenic Psychology; D012917:Social Adjustment