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


METHODS
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.
Jung
R E
RE
Department of Psychology, and Clinical and Magnetic Resonance Research Center, University of New Mexico, Albuquerque 87131, USA. rjung@lizard.unm.edu
Yeo
R A
RA
Gangestad
S W
SW
D000015:Abnormalities, Multiple / Q000235:genetics / Q000523:psychology; D000293:Adolescent; D000328:Adult; D015415:Biomarkers; D002110:Caffeine / Q000009:adverse effects*; D000697:Central Nervous System Stimulants / Q000009:adverse effects*; D018592:Cross-Over Studies; D005260:Female; D007839:Functional Laterality / Q000187:drug effects / Q000235:genetics; D020022:Genetic Predisposition to Disease / Q000523:psychology*; D006801:Humans; D007206:Individuality; D008297:Male; D008570:Memory, Short-Term / Q000187:drug effects*; D014706:Verbal Learning / Q000187:drug effects*
D015415:Biomarkers; D000697:Central Nervous System Stimulants; D002110:Caffeine