Evaluating gene x psychological risk factor effects in the pathogenesis ofanxiety: A new model approach

The present study evaluated the singular and interactive effects of a funct ional polymorphism (variation) in the serotonin transporter (5-HTT) gene an d a psychological trait (anxiety sensitivity [AS], i.e., fear of arousal sy mptoms) in predicting subjective and physiological responses to a 35% carbo n dioxide (CO2) challenge in a community sample (N = 72). Genotypes were di vided into 2 groups in accord with prior research. Findings were partially supportive of the hypothesized risk model. These indicated that the Group L genotype (homozygous for the l allele), compared with the Group S genotype (homozygous fur the s allele plus heterozygous individuals), predicted gre ater fearful response to the biological challenge. There was also an AS X G enotype interaction predicting heart rate variability (HRV) in response to the CO2, suggesting that high AS plus Group L status predicts decreased HRV .