Antidepressants, taken by some 8.6 million people in the UK, could raise the risk of motor neurone disease, a major study has suggested.
Scandinavian researchers also found that other commonly prescribed drugs, like anxiolytics used to treat anxiety disorders, sleeping pills and sedatives were also linked to an increased risk of the disabling condition.
Motor neurone disease, of which amyotrophic lateral sclerosis (ALS) is the most common form, is an incurable, muscle-wasting condition that eventually stops a patient from being able to move, talk and even eat.
Now, research has suggested that being prescribed any of these medications just twice over the course of a lifetime could raise the chance of developing the condition by up to 34 per cent.
Scientists found the risk remained even if the drugs were taken more than five years before diagnosis.
However other scientists have urged caution over the results of the study, suggesting the link lies with the fact mental health patients are more likely to develop MND, rather than medication.
Professor Ammar Al-Chalabi, a specialist in complex disease genetics at King’s College London warned: ‘Association is not causation. That is especially important here.
‘We already know that some of the genetic variants that nudge people towards schizophrenia for example, overlap with variants that nudge people towards ALS.
ALS or ‘locked-in’ syndrome can lead to paralysis and eventually death. The acclaimed scientist Stephen Hawking famously suffered from it
‘It may not be use of the medication that increases ALS risk, but that the need for the medication is a signal that someone is already at increased genetic risk.’
The authors of the study, from various Scandinavian institutions, note that depression, anxiety, and sleep disturbances have been shown to have ‘detrimental effects’ on brain cells, resulting in ‘structural brain change concurrent with ALS’.
MND, which includes ALS, is a progressive disease that affects around 5,000 adults in the UK, and was famously suffered by the physicist Stephen Hawking.
In the study, which was conducted in Sweden, experts looked at 1,057 patients with an average age of 67, who were diagnosed with the disease between January 2015 and July 2023, as well as medications they had taken.
Researchers followed the patients for an average of 1.33 years after their diagnosis.
They matched these patients with a group of healthy controls to look for differences that could contribute to the disease.
Writing in the journal JAMA open network, the researchers found prescribed use of anxiolytics was associated with 34 per cent increased risk of developing MND.
Taking antidepressants, meanwhile, was linked with a 26 per cent raised chance, and sedatives and sleeping pills 21 per cent.
Taking psychiatric drugs such as anti-depressants, anti-anxiety medications, hypnotics and sedatives has been linked with an increased risk of the most common form of MND
The use of antidepressants pre-diagnosis in particular was also associated with a faster rate of functional decline.
Lead author, Dr Charilaos Chourpiliadis, said that more work still needs to be done to understand the link.
However, he said: ‘Closer monitoring in younger patients with psychiatric symptoms might lead to an earlier ALS diagnosis.’
Dr Brian Dickie, chief scientist at MND Association also flagged that the study may be flawed, because the most common genetic risk factor for ALS—a repeat expansion in the C9orf72 gene—is most prevalent in the Scandinavian population.
‘A study in the Swedish population will most likely have a higher proportion of people with this particular genetic form of the disease,’ he explained.
‘Not only would higher use of psychiatric medication be likely, but this genetic form is also linked with faster progression and shorter survival, which could explain the association between psychiatric medication and more aggressive disease.’
