Risk taking during decision-making in normal volunteers changes with age
Risk taking in a large cohort of adults (N = 177; ages 17–73) decreased with age, demonstrated by performance on a computer based gambling task, which has previously been shown to be sensitive to certain pharmacological manipulations including tryptophan depletion, lesions of the orbitofrontal cortex and neuropsychiatric disorders such as mania. Aging was also associated with longer deliberation times, poorer decision making, reduced risk taking, but no significant change in delay aversion. Subjects with a higher (NART-estimated) IQ were faster to make decisions and showed a greater modulation of risk-taking. Both sexes showed similar patterns of decision making, although male participants exhibited a greater modulation of risk-taking in response to the probability of winning. The Decision-Gamble task provides a variety of behavioral measures, corresponding to different aspects of impulsivity. Factor analysis of these measures suggested that two independent traits underlies performance on the task in normal individuals: one associated with risk tolerance, and a second associated with delay aversion. Age was related to decreases in the risk tolerance factor, but unrelated to the delay aversion; neither factor was significantly related to verbal IQ. This study thus provides support for the concept that impulsivity can be fractionated into 2 or more components. (JINS, 2004, 10, 590–598.)(Received February 5 2003)
(Revised December 8 2003)
(Accepted January 6 2004)
Key Words: Impulsivity; Gender; Delay-aversion; Frontal lobe.
c1 Reprint requests to: Prof. Barbara J. Sahakian, University of Cambridge, School of Clinical Medicine, Department of Psychiatry, Box 189, Addenbrooke's Hospital, Cambridge, CB2 2QQ, UK. E-mail: [email protected]