The researchers estimate that one in five of the vehicle accidents
among more than 2 million people with ADHD during the study period
could have been avoided if these individuals had been receiving
medication the entire time.
"The patients should be aware of the potential risk of (motor
vehicle crashes), and seek specific treatment advice from their
doctors if they experience difficulties in driving from their
condition," said lead author Zheng Chang, of the Karolinska
Institute in Stockholm, Sweden.
Chang told Reuters Health that motor vehicle crashes claim the lives
of over 1.25 million people around the world each year.
ADHD is a common disorder with symptoms that include poor sustained
attention, impaired impulse control and hyperactivity, he added.
Past studies have found that people with ADHD are at an increased
risk for crashes, and that medication may reduce symptoms and
ultimately improve driving skills.
To examine the risk of crashes with ADHD and how it is influenced by
medication, the researchers analyzed U.S. commercial health
insurance claims between 2005 and 2014.
They identified 2,319,450 people over age 18 with an ADHD diagnosis,
half of whom were over 33 years old. About 1.9 million of them
received at least one prescription to treat their ADHD during the
There are a number of medications used to treat ADHD, including the
brand names Adderall and Dexedrine.
Overall, 11,224 people in the study had at least one emergency
department visit for a motor vehicle crash. Compared to people
without ADHD, the researchers found men with the condition had a 49
percent increased risk of being in a crash and women had a 44
percent increased risk.
When the researchers looked at data for each individual with ADHD,
they found the men's risk of motor vehicle crashes dropped by 38
percent during months when they received prescriptions to treat
their ADHD. Similarly, women's risk fell by 42 percent during months
when they received a prescription.
The study team estimates that 22 percent of accidents among people
with ADHD that occurred during the study period wouldn't have
happened if every individual had been on medications the entire
The reduced risk among people being treated for ADHD was consistent
across all age groups and was not largely influenced by other
medication use, the authors note in JAMA Psychiatry.
[to top of second column]
Chang said the results can't explain why people treated for ADHD
have a reduced risk of crashes, but there are a few possible
"It could be due to alleviation of the core symptoms of ADHD
(inattention, hyperactivity, and impulsivity), as well as to control
of problems that frequently co-occur with ADHD, such as excessive
risk taking, poor control of aggression, and substance use," Chang
said by email.
"I think with psycho-stimulant medications, we’re oftentimes
concerned about side effects and the potential for abuse, but the
focus on those risks can sometimes distract from the benefits people
get from the medication," said Dr. Jonathan Posner, an associate
professor of psychiatry at Columbia University Medical Center in New
Other studies show the benefits of treating ADHD with medications,
he added. For example, one found that people treated for ADHD had a
lower risk of incarceration.
"Psycho-stimulants can reduce some of the really negative
consequences of ADHD and really help people with ADHD lead safer
lives," said Posner, who was not involved with the new study.
The main concern with ADHD medications is abuse, he noted, but the
risk is small if the drugs are taken as prescribed.
In an editorial accompanying the study, Dr. Vishal Madaan and Daniel
Cox, of the University of Virginia Health System in Charlottesville
remind clinicians treating ADHD patients that inattention and
impulsivity symptoms may persist into adulthood. The need to manage
ADHD extends beyond the needs of school and workplace, and crashes
often happen later in the evening when medication wears off.
"Individualizing and optimizing ADHD pharmacotherapy, while being
mindful of adverse effects and the potential for abuse, is the most
prudent way forward," they write.
SOURCE: http://bit.ly/2qrX2Kz and http://bit.ly/2qrNgIj JAMA
Psychiatry, online May 10, 2017.
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