Genetic Determinants of the Acute Effects and Withdrawal Symptoms of Caffeine

The mechanisms underlying caffeine’s acute effects and withdrawal symptoms are not entirely understood. The purpose was to determine whether these effects or symptoms co-exist in clusters, and whether they are associated with polymorphisms in β1- and β2-adrenoceptors. Subjects (n=1271) were from the Toronto Nutrigenomics and Health Study. The acute effects and withdrawal symptoms clustered into 4 and 6 factors, respectively. Subjects with the ADRβ2 Gly16Arg Gly/Arg genotype were more likely than Gly allele homozygotes to report “fatigue” withdrawal symptoms. Among >200 mg/d caffeine consumers, ADRβ2 Gly allele carriers had a greater risk, compared to Arg allele homozygotes, of reporting ‘flu-like somatic’ withdrawal symptoms. Among subjects with the CYP1A2 -163 A>C A/A genotype and 100-200 mg/d caffeine consumers, ADRβ1 Arg389Gly Gly allele carriers had a greater risk, compared to Arg allele homozygotes, of reporting “dysphoric mood” withdrawal symptoms. The findings suggest that β1- and β2- adrenoceptors play a role in caffeine withdrawal.MAS