It's possible that cannabis extract holds the key to managing pain for people living with Parkinson's disease, according to the largest ever study into pain and the condition.
Researchers at the Salford Royal Foundation Trust in Manchester have spent the past six years investigating why some people with Parkinson's experience chronic pain. This is thought to be an issue for more than half of the 145,000 people in the UK living with the disease.
The study, which was funded by Parkinson's UK, conducted a detailed analysis of how persistent pain has an impact on the lives, work and social relationships of some people with this progressive neurological condition.
Researchers found that a change in the gene connected to how the brain responds to cannabis derivatives could influence whether or not people with Parkinson's experience pain. The findings indicated that this change is determined by genes.
Dr Monty Silverdale, consultant neurologist at Greater Manchester Neuroscience Centre, who led the research, said: "This study is significant because it shows the important role of genetics in chronic pain in Parkinson's. Our findings suggest that cannabis-based compounds may be worth investigating as a treatment for pain in Parkinson's."
Dr Beckie Port, research manager at Parkinson's UK, said: "Pain is not a well-known symptom, but people with Parkinson's have told us of the huge impact it has on their health and wellbeing."
Parkinson's disease is a neurological condition in which parts of the brain become progressively damaged over many years. It is more common in men and older people.
The main symptoms of the disease are:
- Involuntary shaking of particular parts of the body (tremors)
- Slow movement
- Stiff and inflexible muscles
Another common problem associated with Parkinson's is dyskinesia, which causes involuntary movements in various parts of the body. Up to half of people with Parkinson's will experience dyskinesia after five years of taking levodopa, one of the main drugs used to treat symptoms of the disease.
This was the focus of another recent study involving Parkinson's UK, which partnered with Neurolixis, an American biotech company, to investigate the effects of the drug NLX-112 on dyskinesia.
The research looked at the potential of NLX-112 to reduce this side effect by decreasing the amount of dopamine released by serotonin cells in the brain. The results showed that, when NLX-112 was used without levodopa, it improved movement problems, and when used with levodopa, it reduced dyskinesia without impacting the effectiveness of the drug.
Dr Arthur Roach, director of research at Parkinson's UK, said: "This promising research on NLX-112 offers hope that we can find a treatment that can tackle dyskinesia, which can make everyday tasks, such as eating, writing and walking, extremely difficult. People with Parkinson's tell us it is one of the most critical issues that impacts quality of life so we're delighted that this project is progressing so positively."