Dopaminergic state modulates shame and contextual emotional responses in Parkinson's disease

Background Shame is frequent in Parkinson's disease (PD) and negatively affects quality of life, yet its dopaminergic modulation remains unclear. Methods We investigated the effect of dopaminergic replacement therapy (DRT) on shame in 41 fluctuating PD patients using an experimental tailored shame induction task. At visit 1, participants were presented with 60 short written scenarios (neutral, non-PD-related shame, PD-related shame). A tailored selection of 12 scenarios (4 per category) was generated in three steps: (1) initial rating of all 60 scenarios on a shame/embarrassment visual analogue scale (VAS); (2) selection of the highest-rated scenarios for shame conditions and lowest-rated scenarios for neutral condition to account for individual emotional relevance; and (3) emotional rating of these scenarios on 10 VAS (fear, sadness, disgust, joy, self- and other-directed anger, shame, embarrassment, guilt, stress) to ensure specificity of shame/embarrassment responses. At visits 2 and 3, patients rated the 12 scenarios once ON- and once OFF-DRT (randomized crossover design) using the same 10 VAS. Results In OFF-DRT state, shame ratings were lower than in ON-DRT for non-PD-related shame scenarios (Zratio = −2.53, p = 0.02), with a similar trend for PD-related shame scenarios (Zratio = −2.02, p = 0.06). Conversely, patients reported higher embarrassment (Zratio = 4.53, p < 0.001), stress (Zratio = 3.49, p < 0.001), and self-directed anger (Zratio = 3.99, p < 0.001) when evaluating scenarios rated as neutral in the ON-DRT state. Conclusions In OFF-DRT state, emotional responses showed altered contextual calibration, with reduced shame in shame-eliciting contexts and increased negative emotions in neutral situations. These findings suggest that dopaminergic state may modulate intensity and appraisal processes of emotions.