Increased striatal dopamine synthesis capacity in gambling addiction

Abstract Background The hypothesis that dopamine plays an important role in the pathophysiology of pathological gambling is pervasive. However, there is little to no direct evidence for a categorical difference between pathological gamblers and healthy controls in terms of dopamine transmission in a drug-free state. Here we provide evidence for this hypothesis by comparing dopamine synthesis capacity in the dorsal and ventral parts of the striatum in 13 pathological gamblers and 15 healthy controls. Methods This was achieved using [18F]fluoro-L-DOPA (FDOPA) dynamic PET scans and striatal regions of interest that were hand-drawn based on visual inspection of individual structural MRI scans. Results Our results show that dopamine synthesis capacity was increased in pathological gamblers compared with healthy controls. Dopamine synthesis was 16% higher in the caudate body, 17% higher in the dorsal putamen and 17% higher in the ventral striatum in pathological gamblers compared with controls. Moreover, dopamine synthesis capacity in the dorsal putamen and caudate head was positively correlated with gambling distortions in pathological gamblers. Conclusions Together these results provide empirical evidence for increased striatal dopamine synthesis in pathological gambling.