Association between DRD4 Polymorphism and Self-Report Dispositional-Envy

Envy is a competitive emotion speculated to involve an interaction between two different neural networks: The mentalizing network, which processes the other's mental and emotional state, and the reward system, which mediates motivation and the experience of pleasure and displeasure. In line with this, we have recently demonstrated that envy involves activation in regions related to the reward system (Dvash et al., in press). Given the well-established role of Dopamine in reward processing and in social cognition, it may be speculated that envy is modulated by the dopaminergic system.

The dopamine D4 receptor (DRD4) is highly distributed in prefrontal and limbic regions. The 48 bp VNTR in the DRD4 exon III varies between 2 and 11 copies, with the 4-repeat being the most common in Caucasians (Vallone, Picetti, & Borrelli, 2000). The 7-repeat has been associated with novelty seeking, extraversion and ADHD, in some but not all studies.

In the present study 115 participants were genotyped for DRD4 exon III polymorphisms, using PCR amplification and gel electrophoresis to analyze the genotype. Participants completed a self-report single-factor Dispositional Envy Scale (DES), measuring individual differences in the tendency to envy (Smith et al., 1999), and a nonverbal task of social cognition. The results indicated that DRD4-7 participants rated themselves as less envious than the DRD4-not-7 participants. Additionally, DRD4-7 participants were less accurate in the understanding non-verbal social cues. These findings suggest that the DRD4-7 allele, which has been related to a less functional dopamine receptor (Asghari et al., 1995) and the efficiency of receptor maturation (Van Craenenbroeck et al., 2005), may be associated with imbalanced reward system and impaired mentalizing abilities which may explain the lower levels of envy ratings reported here.