After adjusting for age, occupation, education, marital status, self-rating anxiety score, and disease status, we observed significant negative associations of catechol-O-methyltransferase (COMT), dopamine receptor D2 (DRD2) gene score and smoking cessation, as well as significant positive associations between ankyrin repeat and kinase domain containing 1 (ANKK1), dopamine transporter (SLC6A3), dopamine receptor D4 (DRD4) gene score and smoking cessation.
Total Activity did not show full moderation by DRD4, though the measure was correlated with maternal anxiety among fetuses in the Anxious Group with a 7R allele; not among fetuses without both factors.
No clear consensus on the role of any individual gene variant in personality modulation emerged, although SLC6A4 haplotypes and the DRD4rs1800955 promoter variant seemed to be more reliably related to anxiety and impulsivity-related traits, respectively.
No research has examined whether DRD4 variation is associated with biased attention for contextually cued emotion stimuli, an important putative intermediate phenotype for a number of pathologies (e.g. depression and anxiety).
However, infants with the 7-repeat DRD4 allele and homozygous for the short form of 5-HTTLPR (7(+), s/s) showed more anxiety and resistance to the stranger's initiation of interaction.