Differences in rates of impairment in adults who use methamphetamine using two sets of demographically corrected norms.

ABSTRACT

Neuropsychologists can expect to meet with increasing rates of patients who use methamphetamine (MA), as MA use is on the rise, often comorbid with other substance use disorders, and frequently accompanied by changes in cognitive functioning. To detect impairment, neuropsychologists must apply the appropriate normative data according to important demographic factors such as age, sex, and education. This study involved 241 adults with and without MA dependence who were administered the Neuropsychological Assessment Battery. Given the high rates of polysubstance use among adults who use MA, we included adults with mono-dependence and poly-dependence on MA and at least one other substance. We compared the rates of adults with and without previous MA dependence classified as impaired on neurocognitive testing when using norms corrected for age, education, and sex versus norms corrected only for age. Norms corrected for age, education, and sex resulted in less frequent identification of impairment compared to norms corrected only for age, but both sets of norms appeared sufficient and similar enough to warrant their use with this population. It may be appropriate to explore the possible implications of discrepancies between education-corrected and non-education corrected sets of scores when assessing impairment in individuals who use MA.