Comparison of Continuous Performance Test Results of Former Morphine and Methamphetamine Users During the Early Abstinence Phase

Chronic abuse of methamphetamine and morphine may result in cognitive impairment with negative consequences for patients’ treatment and rehabilitation. We applied Conner’s CPT II (continuous performance test) to determine the effect of methamphetamine and morphine use on patient performance in terms of type of substance use. The research was performed at the Tehran University of Medical Sciences, Iran, during the autumn and winter of 2014. Twenty-two male patients previously dependent on morphine, twenty-one former methamphetamine abusers, and nineteen healthy controls were assessed by Conner’s CPT II. The patients groups were pure consumers of their drug of choice in the last six months before treatment, and were in their abstinence period without intoxication or withdrawal symptoms. Initially, the potential depression and anxiety levels of volunteers were evaluated with the Hamilton questionnaire, and then a computerized CPT test was performed. Omission errors (P = 0.008) and variability (P = 0.02) in the methamphetamine group and variability in ex-morphine users were significantly higher in comparison with healthy controls (P = 0.004). Significant differences in CPT performance were observed between the methamphetamine group and the healthy control group.