Developmental instability predicts individual variation in verbal memory skill after caffeine ingestion.

Abstract

Objective: To determine the mediating effects of developmental instability on individual differences in response to caffeine.

Background: Individual variation of drug effects might reflect broad genomic factors as well as the direct effects of specific alleles. The current study tested the hypothesis that individual differences in developmental instability, in part determined by genomic characteristics, would predict individual variation in the magnitude of caffeine-induced verbal memory deficits. Minor physical anomalies and fluctuating asymmetry were used as measures of developmental instability.

Method: One hundred participants were (1) administered one version of the Rey Auditory Verbal Learning Test; (2) given a dose of caffeine determined by body weight (3 mg/kg); (3) assessed for minor physical anomalies and fluctuating asymmetry; and (4) given an alternate randomized version of the Rey Auditory Verbal Learning Test.

Results: Consistent with predictions, a composite measure of developmental instability predicted the magnitude of caffeine-induced memory decrements.

Conclusions: These results may have important implications for the genetic underpinnings of individual differences in drug effects.