How might a drug for ADHD help in Parkinson’s?
Scientists reveal how brain imaging could identify people with Parkinson’s who might benefit most from a drug already used in ADHD called atomoxetine. The drug looks to improve cognition in Parkinson’s.
Researchers funded by Parkinson’s UK at the University of Cambridge provide further evidence that a drug used for ADHD might be beneficial for people with Parkinson’s who experience changes in cognition (the way they think and process actions). Their latest research shows the power of using brain scans to identify who might be most likely to benefit from the potential treatment.
Parkinson’s and cognition
Parkinson’s is not just a condition that affects movement, it has many hidden symptoms. Motor symptoms are largely caused by a reduction in levels of the vital brain chemical dopamine and most of the current medication works to boost or mimic the levels of this chemical within the brain. But dopamine is not the only brain chemical altered in Parkinson’s, and by looking at others, researchers can potentially unlock other treatments to manage or treat different symptoms, such as cognition.
Noradrenaline is another brain chemical affected in Parkinson’s, which plays an important role in processing thoughts, attention and behaviour. An imbalance of noradrenaline can lead to cognitive changes. The extent of this chemical imbalance and subsequent impact varies from person to person. It’s thought that changes and damage in the specific region of the brain called the locus coeruleus can impact the levels of noradrenaline.
There has been so much progress treating the motor symptoms of Parkinson’s, but we have not seen the same gains in treating some of the hidden symptoms of Parkinson’s, like cognitive decline and impulsiveness. But we know that this can be a challenging problem for people with Parkinson’s, and their families.
Dr Claire O’Callaghan, Lead Researcher from University of Cambridge
I was diagnosed with Parkinson’s in 2018, and have noticed my cognition has declined, impacting my ability to do what sometimes can be seamless and straightforward tasks. It’s simple moments like when my daughter asks me to help with her homework or I need to multitask while making food and a cup of tea. Depending on the time of day, my ability to confidently do them changes and I feel stupid.
Vicki Mountain
A drug to boost noradrenaline
There is already a drug available and in use for attention deficit hyperactivity disorder (ADHD) that works to improve attention by boosting and rebalancing the levels of noradrenaline in the brain. This drug is called atomoxetine.
Previous research studies led by Professor James Rowe at the University of Cambridge have shown atomoxetine could be helpful for some people with Parkinson’s but there was no easy way to identify individuals who might benefit most from this treatment. Until now. Read more about the previous studies on the National Library of Medicine website.
What’s new?
Researchers funded and supported by Parkinson’s UK set out to understand if a new type of brain scan could help identify people with Parkinson’s who might benefit most from atomoxetine. The researchers conducted a carefully controlled study in 19 people with Parkinson’s, where each person received the active treatment (atomoxetine) and a placebo (dummy treatment) over 2 separate visits. There was also a comparison group of people without Parkinson’s.
The study measured cognition and behaviour by assessing things like how long it took for someone to stop themselves from completing a task. Participants were given a task which involved pressing specific buttons on a keyboard. But occasionally participants would see or receive a signal to stop them mid-task. The stop signals were carefully timed to assess if and how long it took for someone to respond to the new instruction. This helped give the researchers an idea of how the brain was processing certain thoughts and turning them into actions.
The research also involved a new type of brain scan, allowing for detailed visualisation of changes in a region of the brain linked to cognitive decline, to see if there was a link between these changes and how someone responded to the drug.
What was the result?
Atomoxetine improved the ability to inhibit impulsive behaviour: to let the brain "stop and think" before doing the right thing. These changes were especially profound in those with the most damage to their locus coeruleus.
What are the next steps for this research?
The published results add further evidence that atomoxetine, which is already used in the NHS, could be quickly repurposed to become a safe and available treatment. These promising results show that this new type of brain imaging could play a vital role in identifying people with Parkinson’s who might benefit most from this potential treatment. Read the full results of the study on the Oxford Academic website.
This is an exciting step towards individualised therapy for cognitive decline in Parkinson’s as we are now able to identify who this treatment might be suitable for. The next steps will be to carry out a clinical trial with people taking the drug for longer, and to see if it helps cognition on an everyday basis.
Dr Claire O’Callaghan, Lead Researcher from University of Cambridge
Help drive research forwards
This vital research was carried out by researchers at the University of Cambridge. It was funded by Parkinson’s UK and shaped by the involvement of people affected by Parkinson’s. It was also shared on the Parkinson’s UK Take Part Hub as an opportunity for people to participate in.
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