The primary objective of this study is to replicate the finding that performance on the Stroop color-word interference task is predictive of treatment completion in participants with cocaine use disorders and to extend this finding to participants with Methamphetamine use disorders. Secondary objectives include evaluating whether:
1. performance on various neurocognitive measures, including the Stroop, Rey Auditory-Verbal Learning Test (RAVLT), Iowa Gambling Task (GT), Wisconsin Card Sorting Task (WCST), the Barratt Impulsiveness Scale version -11 (BIS-11), and the Frontal Systems Behavior Scale (FrSBe) is predictive of treatment attrition and stimulant use outcomes in METH/cocaine abusers;
2. neurocognitive test performance is associated with oxidative damage, a severe consequence of oxidative stress, in METH/cocaine abusers;
3. oxidative damage is predictive of treatment attrition and substance use outcomes in METH/cocaine abusers,
4. oxidative damage in METH/cocaine abusers is significantly greater than that of a normal comparison group and
5. exploratory analyses reveal a significant relationship among oxidative stress, neurocognitive function, and treatment outcomes in METH/cocaine abusers.
