Background: Methamphetamine (METH) is a widely abused psychostimulant that is associated with neurotoxicity and neurocognitive impairments in adults. However, the effects of METH use on neurocognitive performance of adolescents are unclear.
Methods: Fifty-four adolescent METH users and 74 age-matched comparison subjects (ages 12 to 23 years) were evaluated with a battery of neuropsychological tests. The cognitive domains evaluated include psychomotor (Symbol Digit, Trail Making), executive function (Stroop Interference task, Wisconsin Card Sort task), fine-motor speed (Grooved Pegboard), memory (Digit span and Auditory Verbal Learning Task), as well as attention and working memory (California Computerized Assessment package).
Results: METH users were slower on the Stroop Interference task than the comparison subjects (F(1,114) = 4.33, p = 0.03). METH subjects also performed worse than controls on the Wechsler Adult Intelligence Scale III/Wechsler Intelligence Scale for Children IV (WAIS/WISC) Matrices task (F(1,114) = 4.37, p = 0.04) and performed significantly worse on the Peg Board task than the comparison subjects for both the dominant (F(1,114) = 7.56, p = 0.01) and non-dominant (F(1,114) = 6.75, p = 0.01). Lastly, length of abstinence was associated with improved performance on the Peg Board test with the dominant had (r = -0.34), as well as the WAIS/WISC Forward Digit Span task (r = 0.38)
Conclusions: METH use is associated with impaired executive functions in adolescent users.