Relationship between opioid receptor availability and the five basic personality dimensions ("Big Five"): A PET study with F-18-fluoro-ethyl-diprenorphine (F-18-DPN)

Objectives The relationship between the opioidergic neurotransmission in the ventral striatum and the degree of reward dependence could be demonstrated in preliminary studies. Therefore, the aim of this subsequent study was to systematically investigate the relationship between the opioidergic system and five basic dimensions of personality (neuroticism, extraversion, openness to experience, agreeableness and conscientiousness) in a large cohort of healthy subjects.

Methods 36 healthy male volunteers were recruited for this study. After the personality psychological testing (NEO-FFI) a PET scan was performed using the subtype non-selective opioid receptor ligand F-18-DPN. As a parameter of opioid receptor availability, the binding potential (BP = DVR -1) was calculated on a voxel-by-voxel level using the modified non-invasive Logan plot with the occipital cortex as reference region. BP images were stereotactically normalized using an in-house developed ligand-specific template. The outcome parameters of the personality traits in the NEO-FFI were used for subsequent correlation analyses using SPM8 (p<0.01, corrected for multiple testing).

Results Positive correlations were found between the scores of neuroticism and the BP of the left-middle cingulate (BA 24), and between conscientiousness and the BP of the left temporopolar cortex (BA 38). Negative correlations were detected for the scores of extraversion with the BP of the left posterior cingulate (BA 23 and 31), for openness to experience with the BP of the bilateral posterior cingulate (BA 30), and between agreeableness and the BP with the right inferior parietal cortex, respectively.

Conclusions This first imaging study on the relationship between the opioidergic system and the basic personality dimensions ("big five") in healthy subjects shows that these personality traits correlate with the opioidergic neurotransmission in central areas of the limbic system