Parkinson’s therapy could be used to tackle alcohol abuse

A form of therapy currently used to treat Parkinson’s Disease could prove promising in treating an alcohol use disorder, a new study has suggested.

Parkinson’s is a disease in which parts of the brain become progressively damaged. The symptoms can be both physical and psychological, including involuntary shaking or tremors, slow movement and stiff and inflexible muscles.

Parkinson’s UK estimates that 1 in 37 people in the UK will be diagnosed in their lifetime, with approximately 145,000 people living with the condition in 2020. Men aged between 50 and 89 are 1.4 times more likely to be diagnosed than women.

Now, a study conducted amongst macaque monkeys has concluded that implanting a specific type of molecule into the brain could dramatically reduce alcohol use amongst heavy drinkers, preventing a return to excessive alcohol consumption following a dry period.

The treatment necessitates brain surgery, with researchers believing that it could be life-changing for those experiencing the most severe cases of alcohol use disorder.

Excessive alcohol use can alter nerve tracts in the brain responsible for producing dopamine, a neurotransmitter often associated with pleasure. Dopamine production can impact both physical function and behaviour, altering heart rate, blood vessel and kidney function, sleep, pain processing, mood and movement.

The study implanted a virus carrying the gene that codes for the glial-derived neurotrophic factor - or GDNF – protein. The virus was not harmful and was introduced to a group of rhesus macaque monkeys that voluntarily and heavily drink ethanol diluted in water.

Researchers found that four of the animals who took part in the study experienced a reduction in consumption of more than 90 per cent.

Notably, the procedure outlined in the study is already used in adult patients with Parkinson’s Disease. In children, it is used to treat aromatic L-amino acid decarboxylase deficiency, a rare genetic disorder that can cause mobility issues.

Since the treatment permanently alters the brain through surgery, it would only be made available to those with the most severe forms of alcohol use disorder.

In 2019/2020, Alcohol Change UK notes that in England, 74,618 people underwent treatment with specialist alcohol misuse services.

Co-principal investigator and co-corresponding author Krystof Bankiewicz, professor of neurological surgery at Ohio State College of Medicine in the US, said: “This gene-therapy approach targets changes in dopamine function in the brain’s mesolimbic reward pathway that are caused by chronic alcohol use.

“Our findings suggest that this treatment can prevent relapse without requiring long-term treatment adherence by patients.”

Co-senior author Kathleen Grant, professor and chief of the division of neuroscience at Oregon Health and Science University’s Oregon National Primate Research Centre, said: “Drinking went down to almost zero.

“For months on end, these animals would choose to drink water and just avoid drinking alcohol altogether.

“They decreased their drinking to the point that it was so low we didn’t record a blood-alcohol level.”

“Dopamine is involved in reinforcement of behaviour, and in people finding certain things pleasurable”, Professor Grant added.

“Acute alcohol use can increase dopamine. However, by drinking it chronically, the brain adapts in such a way that it decreases the release of dopamine.

“So when people are addicted to alcohol, they don’t really feel more pleasure in drinking.

“It seems that they’re drinking more because they feel a need to maintain an intoxicated state.”