The effects of DBH, MAOA, and MAOB on attentional biases for facial expressions.

Attentional bias is the interaction that occurs between emotion and attention. Monoamine oxidase and dopamine β-hydroxylase are involved in the balances of neurotransmitters in the cortex. Much evidence has shown that those enzymes play important roles in human emotion and attention. To investigate the potential influences of some functional polymorphisms in DBH, MAOA, and MAOB on attentional bias, we performed a population-based study in a young Chinese Han group. The results indicated that -1021C/T in DBH was associated with index effect of the neutral facial expressions in spatial cueing task (F = 4.940, P = 0.007), and there was a positive correlation between the dosage of C allele and the index effect (r = 0.068, P = 0.040). Furthermore, we found significant interactions between 19-bp Ins/Del in DBH and VNTR of MAOA on attentional biases for negative expressions in spatial cueing task (F = 3.397, P = 0.009) and dot-probe task (F = 2.827, P = 0.024). The present study suggests that DBH and MAOA can influence human attentional biases, and there is a gene-gene interaction between the DBH and MAOA on attentional bias for negative expressions.