Having autism or ADHD could mean a higher risk of premature death when compared to the general population, new research suggests.
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Having autism or ADHD could come with a higher risk of dying earlier than normal, according to new research.

Several previous studies have suggested these neurodevelopmental disorders might be linked with a higher risk of premature death, but findings were inconsistent, according to a new meta-analysis, or review of data from many previous studies, published Monday in the journal JAMA Pediatrics. The meta-analysis examined 27 studies that were based in North America and Europe and published between 1988 and 2021, amounting to more than 642,000 participants.

The new research found that early mortality – which, in the meta-analysis, was usually death in childhood or by midlife – from natural and unnatural causes was more than two times more likely for both people with autism and those with ADHD than for the general population, said the review’s lead author Ferrán Catalá-López, via email. Natural causes included cardiac events and seizures; unnatural causes included unintentional injuries, suicide and homicide.

Among those with ADHD, the number of premature deaths from unnatural causes (847) was higher than expected, but their risk of early death from natural causes wasn’t as significant as that of people with autism, according to the meta-analysis. But Catalá-López, a scientist at the National School of Public Health and Network Centre for Biomedical Research in Mental Health – both at the Institute of Health Carlos III in Madrid – said the findings shouldn’t be viewed as a death sentence.

“The results of our study should not be interpreted as that having any of these disorders means that people who suffer from them will (necessarily) die prematurely due to traffic accidents, poisoning or suicide,” he said via email.

In a commentary on the meta-analysis, neurodevelopment experts Russell A. Barkley and Geraldine Dawson – who weren’t involved in the research – also highlighted how preventive health care can make a difference.

“After all, ELE (estimated life expectancy) is malleable,” wrote Barkley and Dawson, a former clinical professor of psychiatry at the Virginia Commonwealth University Medical Center and the William Cleland Distinguished Professor of Psychiatry and Behavioral Sciences at Duke University, respectively. “Change the adverse health and lifestyle factors affecting it, and one can improve quality of life, as well as life expectancy.”

People with autism or ADHD “frequently die of preventable natural causes,” they also wrote. “This knowledge demands widespread recognition and the implementation of systematic screening and preventive approaches.”

Factors raising early death rate

The authors of the meta-analysis didn’t have details on participants’ lifestyles, socioeconomic factors or specific causes of death. But prior research has highlighted several factors that could explain the higher early death rate among children and young people with autism or ADHD, the authors wrote.

Around 1% of people worldwide have autism, while roughly 5% of people have ADHD, according to the Autism Society and World Health Organization surveys, respectively. People with ADHD or autism have been found to be at higher risk for coexisting mental disorders and neurological conditions such as depression, anxiety, substance misuse or abuse, eating disorders, epilepsy, or conduct or tic disorders.

These groups have also been linked with higher rates of obesity; dental trauma or decay; sedentary behavior or low exercise participation; sleeping problems; migraines; heart disease; and less involvement in preventive practices concerning health, nutrition and dental hygiene, Barkley and Dawson wrote.

Impulsive or inattentive behaviors that are characteristic of these disorders can be contributing factors for injuries and unintentional incidents, according to the meta-analysis.

The editorial’s authors suggested that early mortality could explain something that has stumped clinical researchers for decades: the decline in the prevalence of ADHD with age. About 5% to 8% of children might meet diagnostic criteria for ADHD while that figure falls to up to 5% of adults and nearly 3% of older adults.

Some researchers have thought this declining prevalence might be due to people experiencing fewer ADHD symptoms as they age or not getting rediagnosed. But the findings “make plain that another explanation is the greater loss of individuals with these conditions from the population over time owing to heightened mortality compared with typical peers,” Barkley and Dawson wrote.

What people with autism or ADHD need

Addressing the issue of premature mortality in people with ADHD and autism is challenging and starts with health care providers, both the meta-analysis and editorial authors said.

“Clinicians and health care professionals can be encouraged to routinely collect information on behavioral, medical conditions and health outcomes related to ASD (autism spectrum disorder)/ADHD, emphasizing the need to recognize and address modifiable vulnerability factors and prevent delays in health care provision,” the meta-analysis authors wrote.

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“This approach is imperative for individuals with ADHD (or ASD) as the higher risk for mortality reported in this review could be reduced by doing so,” according to Barkley and Dawson’s editorial.

Some organizations have resources for how children and adults with autism or ADHD can increase their chances of doing things that could help their quality of life or life expectancy, including exercise, dental care and sleep.