Individual differences in positivity offset and negativity bias: Gender-specific associations with two serotonin...

Individual differences in the evaluation of affective stimuli, such as the positivity offset and negativity bias may have a biological basis. We tested whether two SNPs (HTR2A; 102T>C and HTR1A; 1019C>G) related to serotonin receptor function, a biological pathway associated with affective regulation, were differentially related to positivity offset and negativity bias for males and females. Participants were 109 cigarette smokers who rated a series of affective stimuli to assess reactions to positive and negative pictures. Gender × genotype interactions were found for both SNPs. Males with the 102T allele showed a greater positivity offset than males with the 102C allele. For females, in contrast, the 1019C allele was associated with a greater positivity offset than the 1019G allele, whereas the 102T allele was associated with a greater negativity bias than the 102C allele. Identifying how gender differences may moderate the effect of serotonin receptor genes on affective information processing may provide insight into their role in guiding behavior and regulating affect.