TY - JOUR
T1 - The Processing-Speed Impairment in Psychosis Is More Than Just Accelerated Aging
AU - Mathias, Samuel R.
AU - Knowles, Emma E.M.
AU - Barrett, Jennifer
AU - Leach, Olivia
AU - Buccheri, Sebastiano
AU - Beetham, Tamara
AU - Blangero, John
AU - Poldrack, Russell A.
AU - Glahn, David C.
N1 - Publisher Copyright:
© The Author 2017. Published by Oxford University Press on behalf of the Maryland Psychiatric Research Center. All rights reserved.
PY - 2017/7/1
Y1 - 2017/7/1
N2 - Processing speed is impaired in patients with psychosis, and deteriorates as a function of normal aging. These observations, in combination with other lines of research, suggest that psychosis may be a syndrome of accelerated aging. But do patients with psychosis perform poorly on tasks of processing speed for the same reasons as older adults? Fifty-one patients with psychotic illnesses and 90 controls with similar mean IQ (aged 19-69 years, all African American) completed a computerized processing-speed task, reminiscent of the classic digit-symbol coding task. The data were analyzed using the drift-diffusion model (DDM), and Bayesian inference was used to determine whether psychosis and aging had similar or divergent effects on the DDM parameters. Psychosis and aging were both associated with poor performance, but had divergent effects on the DDM parameters. Patients had lower information-processing efficiency ("drift rate") and longer nondecision time than controls, and psychosis per se did not influence response caution. By contrast, the primary effect of aging was to increase response caution, and had inconsistent effects on drift rate and nondecision time across patients and controls. The results reveal that psychosis and aging influenced performance in different ways, suggesting that the processing-speed impairment in psychosis is more than just accelerated aging. This study also demonstrates the potential utility of computational models and Bayesian inference for finely mapping the contributions of cognitive functions on simple neurocognitive tests.
AB - Processing speed is impaired in patients with psychosis, and deteriorates as a function of normal aging. These observations, in combination with other lines of research, suggest that psychosis may be a syndrome of accelerated aging. But do patients with psychosis perform poorly on tasks of processing speed for the same reasons as older adults? Fifty-one patients with psychotic illnesses and 90 controls with similar mean IQ (aged 19-69 years, all African American) completed a computerized processing-speed task, reminiscent of the classic digit-symbol coding task. The data were analyzed using the drift-diffusion model (DDM), and Bayesian inference was used to determine whether psychosis and aging had similar or divergent effects on the DDM parameters. Psychosis and aging were both associated with poor performance, but had divergent effects on the DDM parameters. Patients had lower information-processing efficiency ("drift rate") and longer nondecision time than controls, and psychosis per se did not influence response caution. By contrast, the primary effect of aging was to increase response caution, and had inconsistent effects on drift rate and nondecision time across patients and controls. The results reveal that psychosis and aging influenced performance in different ways, suggesting that the processing-speed impairment in psychosis is more than just accelerated aging. This study also demonstrates the potential utility of computational models and Bayesian inference for finely mapping the contributions of cognitive functions on simple neurocognitive tests.
KW - Bayesian inference
KW - aging
KW - computational psychiatry
KW - digit-symbol
KW - processing speed
KW - psychosis
UR - http://www.scopus.com/inward/record.url?scp=85021828917&partnerID=8YFLogxK
U2 - 10.1093/schbul/sbw168
DO - 10.1093/schbul/sbw168
M3 - Article
C2 - 28062652
AN - SCOPUS:85021828917
SN - 0586-7614
VL - 43
SP - 814
EP - 823
JO - Schizophrenia Bulletin
JF - Schizophrenia Bulletin
IS - 4
ER -