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.

Keywords:

• Cognition
• neuropsychology
• normative data
• substance use disorder
• stimulant

Acknowledgements

We thank Marilyn Huckans, Ph.D. and our participants for their contributions to this project. This material is the result of work supported with resources and the use of facilities at the VA Portland Health Care System (VAPORHCS) and Oregon Health & Science University (OHSU), Portland, Oregon. The corresponding author (K.S.) declares she had full access to all the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis. The authors are or were Veterans Affairs employees (Kate Shirley, MA, Research Assistant, VAPORHCS; Maya O’Neil, PhD, Neuropsychologist, VAPORHCS; Stephen Boyd, PhD, Clinical Psychologist, VAPORHCS; Jennifer M. Loftis, PhD, Research Scientist, VAPORHCS). The contents do not represent the views of the United States Department of Veterans Affairs or the United States Government.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was funded by National Institute on Drug Abuse grant #1U18DA052351-01.