Theses and Dissertations

Effect of Medication on Cognition: Information from a Clinical Sample using a Semi-Flexible Battery of Common Neuropsychological Tests

Date of Award


Document Type


Degree Name



Clinical and Counseling Psychology

Committee Chair

Benjamin D. Hill, Ph.D.


Prescription medications are widely used, particularly among older adults, with 46% of adults overall and 85% of older adults (65 years old and older) using at least one medication (Martin et al., 2019). Three percent of adults overall and 39% of older adults use 5 or more medications, constituting polypharmacy (Kantor et al., 2015). While there are many medications, as well as polypharmacy, that are known to have cognitive effects, many other widely used medications have been inconsistently associated with changes in cognition. Additionally, the degree of change, independent of effects of a possible underlying neurodegenerative process, is unknown. This is problematic for physicians, specifically neuropsychologists, who are tasked with evaluating cognition and providing differential diagnoses for potential cognitive change. OBJECTIVES: The current study sought to evaluate the effects of medication and polypharmacy on global and domain specific cognitive functioning in a broad clinical sample of adults using a comprehensive battery of neuropsychological tests. METHODS: Seven hundred and fifty archival neuropsychological data files were reviewed for inclusion. Four hundred and ninety-seven cases were ultimately retained for analyses (mean age = 40.75, SD = 14.61, range = 18-80 years). Most of the sample identified as xviii female (52%) and Caucasian (94%). The number of medications used by study participants ranged from 0 to 14 (M = 2.64, SD = 2.50) and 11.3% reported taking 6 or more medications. All participants completed a large flexible battery of common neuropsychological tests, which allowed for calculation of overall test battery performance and cognitive domain specific performances. RESULTS: Two-way Analyses of Covariance analyzed the interaction and main effects of specific medication groups and polypharmacy on global cognitive performance, as measured by the overall test battery mean and intra-individual variability. Significant main effects of analgesics, triptan, polypharmacy on IIV were identified. No significant interaction or main effects were identified for two-way Multivariate Analyses of Covariance evaluating the effects of medication and polypharmacy across nine cognitive domains. CONCLUSIONS: Subjects taking analgesic medications, and medications from the triptans drug class, showed more cognitive variability over the course of a neuropsychological evaluation, compared to those not taking these medications. Additionally, subjects without polypharmacy showed more cognitive variability than those taking more than 5 medications and those who were not taking any medications. Study limitations and clinical implications of these findings are discussed.

This document is currently not available here.