Want the best of The Telegraph direct to your email and WhatsApp? Sign up to our free twice-daily Front Page newsletter and new audio briefings. The study found that urological anticholinergics were associated with 18 per cent increased risk of dementia, while antidepressants were associated with an 11 per cent increased risk.Nationally, 7.1 per cent of all people over the age of 65 suffer from the disease.Professor Clive Ballard, Professor of Age-Related Diseases at University of Exeter Medical School, said: “This is a very large and well conducted study demonstrating a clear association between the use of drugs with anticholinergic side-effects and the risk of dementia / cognitive decline.“The important thing is that even individual drugs which only have a very modest anticholinergic effects, when taken in combination with other drugs, can lead to a combined anticholinergic burden that may have a significant impact on cognition, highlighting the importance of care medication review.” Antidepressants, bladder drugs and Parkinson’s drugs were looked at in the study Credit:vasiliki Chris Fox, Professor of Clinical Psychiatry at UEA’s Norwich Medical School and one of the authors, said the the study revealed a “potentially important risk”.“Doctors and patients should therefore be vigilant about using anticholinergic medications,” he said.“They need to consider the risk of long-term cognitive effects, as well as short-term effects associated with specific drugs when weighing up risks and benefits.”Anticholinergics work by blocking a key neurotransmitter called acetylocholine.Professor Fox said the medication may cause dementia by prompting a “inflammatory cascade” which then leads to deposits of tau and amyloid, known to be a factor in the disease. Meanwhile a dementia risk was also associated with the bladder drugs Tolterodine, Oxybutynin and Solifenacin, as well as the Parkinson’s drug Procyclidine.It is believed nearly 2,000,000 people in England are taking these and other similar drugs.No link was found between anticholinergics antihistamines and those prescribed for stomach cramps, dispelling previous fears. Anticholinergics, which have been available for more than 50 years, target a part of the nervous system affecting learning and memory, as well as the heart, eye, stomach mouth and bladder.While short-term side-effects such as confusion are well known, the new research is the first to examine the possible effects across a wide population and over a long period of time, as well as by medicine.Scientists at the University of East Anglia (UEA) and Aston University studied approximately 27 million prescriptions from more than 324,000 NHS patients going back 20 years.The structure of the study means a causal link cannot be proved, however the researchers noted there was a greater incidence of dementia among patients prescribed more anticholinergic antidepressants and other medication. Antidepressants may significantly increase the risk of developing dementia, experts have warned.A major new study, published in the British Medical Journal, found a “robust link” between the degenerative disease and the medication, even when taken up to 20 years before a diagnosis.It suggests some patients with long-term exposure to the drugs could face a 30 per cent increased chance of dementia.Researchers warned there may be 20,000 people currently suffering from dementia as a result of taking the medication, part of a wider group called anticholinergics, which is also prescribed for patients with bladder conditions and Parkinson’s disease.The Government medicines safety regulator said it was scrutinising the new findings and last night leading medics called on colleagues to consider alternative prescriptions, although they cautioned patients not to abandon the drugs before consulting their doctor.The antidepressant medications most implicated by the study include Amitriptyline, Dosulepin and Paroxetine.