Serotonin and emotion processing in Parkinson's Disease 1
Research type
Research Study
Full title
Effects of serotonin on emotion and motivation processing in Parkinson's disease
IRAS ID
245835
Contact name
Masud Husain
Contact email
Sponsor organisation
University of Oxford / Clinical Trials and Research Governance
Duration of Study in the UK
2 years, 0 months, 0 days
Research summary
Summary of Research
The purpose of this mechanistic study is to investigate how modulation of the brain neurotransmitter serotonin affects emotion and motivation processing in Parkinson’s disease (PD).PD is primarily associated with motor symptoms, but recent research also highlights altered processing of emotions and changes in motivation. The underlying mechanism of these symptoms is unknown, although some research has implicated the neurotransmitter serotonin. Citalopram is usually used as an antidepressant, and its effectiveness is thought to rely on increasing the level of serotonin at synapses (the connections between nerve cells). Here we test in a proof-of-concept mechanistic study whether it is possible to alter emotional processing and motivation in Parkinson's disease patients as assessed by computerised tests (not clinical endpoints).
We will recruit 36 patients with Parkinson’s disease. The study will involve two phases, lasting 7 days each. In the first phase, participants will receive either citalopram or placebo. In the second phase, participants will receive the alternative compound, so that every participant will have received each of the two compounds at the end of the study. On the seventh day of each phase, participants will be asked to complete simple computer tasks and fill out questionnaires. There will be a break of 14 days between each phase. The work will take place at the Department of Clinical Neurosciences, and the Department of Experimental Psychology, University of Oxford.
A similar non-CTIMP, mechanistic study has previously been performed for the same duration of each phase in patients with depression (Godlewska et al, 2012).
Summary of Results
The objective of this study was to investigate the contribution of serotonin (a chemical in the brain) on motivated decision-making in twenty patients with Parkinson's disease compared to twenty healthy people without Parkinson's. Parkinson's patients were overall less motivated on an effort- and reward-based decision-making task. Citalopram, which increases the level of serotonin, increased or decreased willingness to exert effort for reward, depending on whether baseline motivation was high or low, respectively. The results provide evidence for a role of the serotonin in influencing some aspects of motivated decision-making in Parkinson's patients.REC name
South Central - Oxford B Research Ethics Committee
REC reference
18/SC/0524
Date of REC Opinion
13 Dec 2018
REC opinion
Further Information Favourable Opinion