Aumann, Megan A.; Lee, Sean J.; Song, Alexander K.; O’Rourke, Kaitlyn R.; Trujillo, Paula; Yan, Yan; Kang, Hakmook; Claassen, Daniel O. “Behavioral Effects of Stimulated Dopamine Release and D2-like Receptor Displacement in Parkinson’s Patients with Impulse-Control Disorder.” International Journal of Molecular Sciences 26, no. 8 (2025): 3866. https://doi.org/10.3390/ijms26083866.
In Parkinson’s disease (PD), problems with dopamine (a brain chemical) in certain brain areas are linked to impulsive and compulsive behaviors (ICBs) like gambling or overeating. However, how sudden changes in dopamine affect mood, where in the brain this happens, and how it differs between patients with and without these behaviors is not well understood.
In this study, 20 people with PD took part: 10 with impulsive behaviors (PD-ICB) and 10 without (PD-C). They were given either a placebo or a dose of a drug called dextro-amphetamine (dAMPH) that stimulates dopamine release. Their mood was measured using several questionnaires that ask how they feel.
Brain scans were also done to measure how much dopamine was available in specific brain areas.
The results showed that after taking dAMPH, everyone’s positive mood increased, but the increase was bigger in people with impulsive behaviors. Changes in mood were linked to dopamine release in several brain regions involved in emotion and reward, including the ventral striatum, caudate, amygdala, and orbitofrontal cortex.
These findings suggest that sudden dopamine release in these brain areas affects mood, and that differences in dopamine activity might explain why some people with PD develop impulsive behaviors. This could also help understand side effects of dopamine-related treatments in Parkinson’s disease.
Figure 1. Box-and-whisker plots showing the median and quartile distribution for PANAS positive scores in all PD subjects (left) and split into PD-ICB (middle) and PD-C cohorts (right) in both off-dAMPH (blue) and on-dAMPH (red) conditions. ** Indicates statistically significant results after multiple comparisons correction at p< 0.05, and *** at p < 0.01.