The review, published in this week's (February 25) issue of the scientific journal Neuron, illustrates that persistently elevated levels of dopamine in the brain promote the development and maintenance of addictive behaviours.
Addiction is a complex health and societal problem that can destroy lives and damage communities. Brain imaging studies have shown that addiction severely alters brain areas critical to decision-making, learning and memory, and behavior control. In order to learn how to control or manage the disorder, it is necessary to understand the underlying biological mechanisms. Researchers have turned to Parkinson's disease to study addiction, successfully using one disease to learn about another. Although seemingly very different, dopamine plays a role in both disorders and some of the same systems in the brain are affected. Parksinson's disease is often thought as just affecting movement but, it also consists of cognitive, behavioural and mood symptoms, which are now being recognized as a major source of disability.
Dopamine is a neurotransmitter, or chemical messenger in the brain that is involved in brain processes that control movement, emotional response and the ability to experience pleasure, reward and pain. Parkinson's patients lack dopamine and are often treated with dopamine agonists, medication that mimics dopamine action.
"In some instances Parkinson's disease (PD) patients become addicted to their own medication, or develop behavioural addictions such as pathological gambling, compulsive shopping or hypersexuality," says Dr. Alain Dagher, neurologist at the MNI and co-author of the review.
"This is surprising because PD patients typically have a very low incidence of drug abuse and display a personality type that is the opposite of the typical addictive personality. These rare, addictive syndromes, which appear to result from excessive dopaminergic treatment, illustrate the link between dopamine, personality and addiction."
PD patients treated with dopamine agonists had an incidence of pathological gambling as high as 8% compared to less than 1% in the general population. In PD patients who develop addictive disorders, the problems started soon after starting dopaminergic therapy and stopped after treatment was discontinued. It was found that adjusting the dosage and combination of medication resolved the addictive symptoms, while maintaining the same motor benefit.
The phenomenon of addiction induced by dopamine medications can also tell us something about vulnerability to addiction in the general population. Not everyone is equally vulnerable, and it now appears that the propensity to become addicted is in part hereditary. Many of the genes implicated in addiction appear to affect brain levels of dopamine.
Studies show that that dopamine acts in an area of the brain known as the ventral striatum, which receives input from other areas such as the hippocampus and amygdala. It may be through this region that dopamine promotes addictive behaviours.
Understanding brain function that leads to drug addiction may help in the development of drugs to block drug-craving and drug-seeking behaviours in the general population as well as refine disease treatment for Parkinson's patients.
Anita Kar | EurekAlert!
Study suggests possible new target for treating and preventing Alzheimer's
02.12.2016 | Oregon Health & Science University
The first analysis of Ewing's sarcoma methyloma opens doors to new treatments
01.12.2016 | IDIBELL-Bellvitge Biomedical Research Institute
A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.
Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...
In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.
“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...
The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.
The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...
Broadband rotational spectroscopy unravels structural reshaping of isolated molecules in the gas phase to accommodate water
In two recent publications in the Journal of Chemical Physics and in the Journal of Physical Chemistry Letters, researchers around Melanie Schnell from the Max...
The efficiency of power electronic systems is not solely dependent on electrical efficiency but also on weight, for example, in mobile systems. When the weight of relevant components and devices in airplanes, for instance, is reduced, fuel savings can be achieved and correspondingly greenhouse gas emissions decreased. New materials and components based on gallium nitride (GaN) can help to reduce weight and increase the efficiency. With these new materials, power electronic switches can be operated at higher switching frequency, resulting in higher power density and lower material costs.
Researchers at the Fraunhofer Institute for Solar Energy Systems ISE together with partners have investigated how these materials can be used to make power...
16.11.2016 | Event News
01.11.2016 | Event News
14.10.2016 | Event News
02.12.2016 | Medical Engineering
02.12.2016 | Agricultural and Forestry Science
02.12.2016 | Physics and Astronomy