Illicit substance use increases oxidative stress and oxidative stress has been found to be associated with deficits in memory, attention, and problem-solving. This type of executive dysfunction, which impairs the ability to learn and apply new, more adaptive behaviors, may serve to increase vulnerability to stimulant use.
This article, in-press at American Journal of Drug and Alcohol Abuse and written by Theresa Winhusen, Jessica Walker, Greg Brigham, and colleagues, reports on an ancillary study of National Drug Abuse Treatment Clinical Trials Network protocol CTN-0031 (Stimulant Abuser Groups to Engage in 12-Step (STAGE-12)) that aimed to test a model of the association among oxidative DNA damage and stimulant use, executive function, and stimulant-use outcomes. Recovery Centers of King County, part of the Pacific Northwest Node, participated in this study.
The researchers found that while more recent cocaine use (use within the past 30 days) was associated with greater oxidative DNA damage, the results did not support the hypothesized relationship between oxidative DNA damage, executive dysfunction, and stimulant use outcomes for cocaine-dependent patients.
However, support for the model was found for methamphetamine-dependent patients, with oxidative DNA damage significantly greater in methamphetamine-dependent patients with executive dysfunction and with executive dysfunction being a significant mediator of oxidative DNA damage and stimulant use during active treatment.
Conclusions: The present results suggest that methamphetamine is neurotoxic, as assessed by executive dysfunction, but cocaine is not, which is consistent with research finding that methamphetamine, but not cocaine, is toxic to dopamine and serotonin neurons. These findings provide preliminary support for a model in which oxidative damage resulting from methamphetamine use results in executive dysfunction, which in turn increases vulnerability to future stimulant use.
Citation: Winhusen TM, Walker J, Brigham GS, et al. Preliminary Evaluation of a Model of Stimulant Use, Oxidative Damage and Executive Dysfunction. American Journal of Drug and Alcohol Abuse 2013 (in press).