Parkinson's disease, a study reveals the relationship between therapy and risk propensity in patients with impulse control disorder
Some Parkinson's drugs acting on dopamine may increase, only in predisposed patients, a certain propensity to risk, without compromising cognitive ability. This is the result of a study coordinated by the BioRobotics Institute of the Sant'Anna School in Pisa, in collaboration with the Careggi University Hospital and the School of Economics and Management of the University of Florence. The results of the experiments suggested that these drugs can alter decisions in a minority of patients.
“Our hypothesis is that this effect may not be due to the medication directly causing decision-making impairments, but rather it acts as a trigger in patients particularly predisposed. It is essential to investigate this phenomenon further to develop more targeted therapies and prevent the onset of these disorders in patients who are especially sensitive to the dopaminergic therapy” explains Alberto Mazzoni, Professor of Bioengineering at the Sant'Anna School, principal investigator of the Computational Neuroengineering Lab and study coordinator.
How to evaluate the effects of drugs on decision-making disorders: a game proposed by researchers
Parkinson's disease is a neurodegenerative disorder that mainly affects motor control, causing symptoms such as tremor, rigidity and difficulty in movement. These problems can be reduced by giving patients appropriate medication. However, there are also non-motor symptoms, such as alterations in decision-making processes that result in so-called impulse control disorders that can increase behaviour such as gambling and compulsive shopping in people who are already predisposed.
“Impulse control disorder - explains Silvia Ramat, neurologist and head of the Parkinson Unit at the Careggi University Hospital - is a behavioural disorder that in some cases can complicate Parkinson's disease, causing personal, family and social problems. The study delves into an important aspect of Parkinson's disease and will help doctors to implement an increasingly personalised therapy”.
The study coordinated by the BioRobotics Institute examined the effects of dopaminergic anti-tremor drugs on the decision-making ability of patients with Parkinson's, with and without impulse control disorder, using a behavioural test developed together with the School of Economics and Management of the University of Florence. The researchers asked two categories of Parkinson's patients, with and without decision-making disorders, to participate in a video game in which they had to make more or less risky choices. The patients had to choose several times between two options: one with a low payout but a minimal risk of loss, and another with a high payout but a higher risk of loss. After each choice, the patients were informed of the outcome and had to adopt a strategy that would make them win as much as possible.
The test results and the gradual increase towards risky choices
“Without drugs, both groups correctly adopted a low-risk strategy and after taking the drugs, patients without decision disorders maintained this strategy. In contrast, after drugs, the patients with decision-making disorder forgot they had learned to avoid risky choices, slipping back toward them” says Fabio Taddeini, first author of the study.
