People with autism are at a significantly greater risk of developing memory-robbing dementia, experts warn. 

At the world’s largest dementia conference this week, researchers suggested that the swift rise in autism spectrum disorder (ASD) could potentially increase the risk of dementia, a condition affecting 9 million Americans.

One study, which analyzed data from nearly 800,000 individuals, found that adults with autism and other intellectual disabilities were up to three times more likely to show signs of cognitive decline and dementia.

And even autistic people under 50 were 30 percent more likely to be diagnosed with dementia than their neurotypical peers.

Another study revealed that nearly one in three autistic adults displayed at least two signs of cognitive decline, such as forgetting words or wandering at night.

Experts in Pennsylvania and Washington DC suggested the increased risk could be due to higher rates of other conditions in people with autism, like depression and diabetes, which have been shown to cause damaging inflammation in the brain.

Drugs that block neurotransmitters responsible for memory like bladder drugs and Benadryl may also be to blame, one of the studies suggested. 

The emerging research comes as one in 31 children in the US now have autism, a staggering increase from about one in 150 in the early 2000s.

Newly presented research shows autism may increase dementia risk (stock image)

Experts suspect the surge is due to doctors getting better at detecting the disorder and increased awareness. 

However, health secretary Robert F Kennedy Jr earlier this year announced a series of studies to hone in on ‘environmental toxins’ he believes are responsible, including pollution, ultra-processed foods and ultrasound scans.

Dr Lindsay Shea, one of the study authors and director of the Policy and Analytics Center at Drexel University’s AJ Drexel Autism Institute, said during a conference presentation: ‘We see that autistic children have grown up to become mostly autistic adults and now older adults. 

‘The first generation of autistic adults are now in their 80s and 90s.’

Dementia is also on the rise, with experts suspecting it could strike 14million Americans by 2060.

In one study presented this week at the Alzheimer’s Association International Conference, researchers pulled Medicare and Medicaid claim data from 2017 to 2019 of nearly 800,000 Americans ages 30 and over. 

Participants were split into four groups: autism, autism plus intellectual disability (fetal alcohol syndrome, for example) or intellectual disability.

There were 60,087 people in the autism group, 101,748 with both autism and intellectual disability and 632,607 with only an intellectual disability.

They were then compared to about 760,000 adults in the general population. 

The researchers found 30 percent of adults over 65 with autism were diagnosed with dementia compared to 19 percent in the general population, a 45 percent increased risk.

The difference was even greater for people with autism and intellectual disability, as 32 percent of this group developed dementia. 

Among 50- to 64-year-olds, eight percent of people with autism had dementia compared to five percent of the general population, a 46 percent difference. And people with autism and another intellectual disability were three times more likely to have dementia than neurotypical people. 

The team also found 1.1 percent of autistic individuals between ages 30 and 49 had dementia compared to 0.8 percent in the general population, a 31 percent difference.

Dr Shea said: ‘This data supports the idea of both early onset and higher prevalence rates of dementia in these populations.’

Another study from George Washington University looked at two samples of 210 independent and 500 dependent autistic adults who reported signs of cognitive decline like trouble recalling tasks or words, impaired judgment or changes in behavior. 

Caregivers also noted their dependent loved ones wandered at night, avoided initiating conversation and lost track of time. 

Independent participants were between 42 and 81 years old with an average age of 54. Autistic adults dependent on a caregiver were 18 to 68 years old with an average age of 

About 30 percent of independent autistic people had two or more signs of cognitive decline while 10 percent of dependent adults had caregivers report at least one sign of impairment.

The most common cognitive decline indicators were less interest in activities, everyday thinking problems and judgment issues.

Dr Gregory Wallace, study author and associate professor at George Washington University, said: ‘That’s very high given the average age.’

Dr Wallace believes certain medications could be to blame. Nearly two-thirds of adults in the study were taking anticholinergics, drugs that block the neurotransmitter acetylcholine, which is crucial for muscle contractions, memory, learning and other functions.

The above map shows dementia risk divided by geographic region

They’re used to treat a variety of issues including urinary incontinence, gastrointestinal distress, chronic obstructive pulmonary disease (COPD) and Parkinson’s disease, which are all more common in autistic people than the general population. 

These drugs are also sold over the counter in as Benadryl, Tylenol, Advil PM and Dramamine, among others.

It’s thought that anticholinergics blocking the neurotransmitter acetylcholine over repeated use could lead to permanent damage to cognitive functions. Autistic people also tend to be more sensitive to medications.

The increased dementia risk also may be tied to chronic conditions like depression, diabetes and high blood pressure, which induce harmful inflammation in the brain and damage neurons responsible for memory. 

Dr Shea said: ‘This is particularly noteworthy because all of these diagnoses are more prevalent in autism than they are in the general population.

‘We know that autistic adults are often unemployed, often don’t have community integration and have high rates of obesity.’