Psychological Effects of Levodopa in Parkinson's Disease

Inclusion Criteria: * Adults above 18 years old * Male or female * Diagnosed with Parkinson's disease * Able to understand instructions, neuropsychological tests and provide written informed consent * Able to understand the locally used language of the experimental site and speak fluently * Presence of neuropsychiatric fluctuations, defined as the sum ≥ 3 of items included in the Ardouin Scale of Behaviour in Parkinson's Disease (ASBPD) part 2 Exclusion Criteria: * Structural brain disease other than Parkinson's disease * Substance abuse and/or dependence (other than DRT) * Ongoing depression with suicidal ideation * Severe tremors/dyskinesia/ interfering with MRI performance * Participating in a pharmacological study * Inability to provide informed consent (legal guardianship) * MRI contraindications * Pregnancy