Dopamine response to psychosocial stress in humans and its relationship to individual differences in personality traits.

BACKGROUND

Previous studies have reported inter-individual variability in the dopamine (DA) response to stress. This variability might be related to individual differences in the vulnerability to experience the negative effect of stress.

OBJECTIVE

To investigate whether personality traits as measured by the revised NEO personality inventory explain variability in DA response to a psychosocial stress task.

METHODS

Eleven healthy adults, mean age of 26 ± 3.87 underwent two positron emission tomography (PET) scans using the dopamine D(2/3) agonist, [11C]-(+)-PHNO under a control and stress condition. The simplified reference tissue model (SRTM) was used to obtain [11C]-(+)-PHNO binding potential (BP(ND)). Stress-induced DA response was indexed as a percent change in [11C]-(+)-PHNO BP(ND) between control and stress conditions. The regions of interest were defined into D2-rich regions, which included the Associative and Sensorimotor Striatum (AST and SMST); D(2/3) mixed regions, which included the limbic striatum (LST) and globus pallidus (GP); and D3-rich region, which included the Substantia Nigra (SN).

RESULTS

Several personality traits within the Neuroticism and Openness to Experience domain were significantly correlated with blunted DA response to stress. Specifically, the Angry-Hostility, Vulnerability, and Depression trait were associated with blunted DA stress response in the AST (r = -0.645, p = 0.032), LST (r = -0.677, p = 0.022) and GP (r = -0.736, p = 0.010), respectively. The Openness to Values was correlated with a decreased DA release in the SN (r = -0.706, p = 0.015).

CONCLUSION

Variability in DA stress response might be related to individual differences in personality.