Regular, over-the-counter drugs used to treat a number of common ailments could significantly increase the risk of developing dementia.
According to a large-scale study carried out by the University of Washington, pills to treat insomnia, hay fever and heart problems are among those capable of doubling a person's chance of suffering from the mental illness in old age.
Dementia is a category of brain diseases linked to a long-term and gradual decrease in cognitive ability, affecting memory, mood and ability to speak.
Tablets found to pose a danger to health included Nytol, Benadryl and Piriton, and the risk appeared to continue for years after usage stopped.
The researchers looked at 3,434 people aged 65 and over who did not suffer from dementia at the start of the study, and monitored their use of over-the-counter and prescription drugs for 10 years after that.
In particular, they focused on anticholinergic drugs, which work by blocking the chemical transmitter acetylcholine in the nervous system.
By the end of the study, it was found that people who consumed a daily dose of this category of drugs more than 1,095 times during the period were 54 per cent more likely to have dementia by the end of it. For those who had between 366 and 1,095 doses, risk increased by 23 per cent.
Dementia afflicts a huge portion of the country's aged population – more than 300,000 people are currently diagnosed with it each year, and 10 years from now it is predicted that one million people will be living with the problem the UK.
In light of the findings, the researchers have advised users in the UK not to take the pills unless it is completely necessary.
George Savva, a lecturer at the University of East Anglia’s school of health sciences, told The Times:
If strong anticholinergics increase dementia risk then there is an important opportunity to prevent dementia by discouraging their long- term use.But we have to remember that anticholinergics do vastly improve quality of life for a lot of people, and so it is important to weigh up the benefits against possible harms. It is important for individuals to discuss the benefits and harms with their doctors before stopping any medication.
Some in the industry are more sceptical of the results, however, since the results do not definitively prove there is a link between the drugs and dementia. In particular, individuals who take the pills in the first place may be more prone to illness.