ADHD May Increase Risk of Traffic Accidents

ADHD patients had increased risk of traffic accidents but medication may lower risk in men

(RxWiki News) Millions of traffic accidents happen each year, and they are often due to people being distracted. People with ADHD pose a unique risk.

A recent study found that ADHD patients were at an increased risk of serious traffic accidents.

The researchers discovered that the use of ADHD medication was linked to a reduced rate of accidents among men with ADHD.

"Discuss the risks and benefits of ADHD medication with your psychiatrist."

The lead author of this study was Zheng Chang, PhD, from the Department of Medical Epidemiology and Biostatistics at the Karolinska Institutet in Stockholm, Sweden.

The study included 17,408 men and women diagnosed with ADHD between January 1, 2006 and December 31, 2009. These participants were 18 to 46 years old in 2006. All participants were from Sweden.

A serious traffic accident was considered an accident that resulted in an emergency room visit or death.

This study also included a control group of people with no ADHD diagnosis, chosen from the general population of Sweden. Each study participant was matched with 10 controls by age, sex and residential area at the time of diagnosis.

The findings showed that 58 percent of the men had been prescribed ADHD medication, and 7 percent were involved in at least one serious traffic accident.

In the male control group, less than 1 percent of participants were prescribed ADHD medication and 3 percent had been involved in at least one major traffic accident.

Of the women, 65 percent had been prescribed ADHD medication and 4 percent had been in at least one serious traffic accident.

Less than 1 percent of the female control group was prescribed ADHD medication and 2 percent had been involved in at least one major traffic accident.

The researchers determined that men with ADHD were 47 percent more likely to be involved in a traffic accident than the men with no ADHD diagnosis.

Compared to the women with no ADHD diagnosis, the women with ADHD were 45 percent more likely to be involved in an accident.

The findings of this study also revealed that the use of medication reduced the rate of accidents by 29 percent among men.

The researchers considered a participant to be 'on medication' if they picked up two prescriptions within a period of less than six months, and a participant was considered 'off medication' if six or more months passed between prescription pick-ups. 

Medication use did not significantly affect the rate of accidents among the female participants.

The researchers then compared medicated periods versus non-medicated periods in each individual participant.

For male participants, individual use of medication versus no use of medication was associated with a 58 percent decrease in the accident rate.

For individual women, ADHD medication use did not significantly affect the rate of accidents.

At the end of the study period, 37 percent of the men with ADHD were on medication. Therefore, the researchers estimated that 41 percent of the accidents among the men with ADHD were linked to periods of non-medication.

Because there were not significant associations between ADHD medication and accident risk in women, the researchers concluded that only the men with ADHD were at an increased risk for a serious traffic accidents, and this risk was reduced with ADHD medication.

The authors mentioned a few limitations of their study. First, the researchers measured ADHD medication use by prescription records, and some of the participants may not have taken their medication regularly. Second, the small study population did not allow the researchers to compare the effects of different types of ADHD medication. Third, the study outcome was based on accidents that ended in death or emergency room visits; there may have been other accidents with less severe results. Lastly, the researchers did not have data on who or what caused each accident.

This study was published on January 29 in JAMA Psychiatry.

The Swedish Research Council, the Swedish Council for Working Life and Social Research and the National Institute of Child Health and Human Development provided funding.

Review Date: 
January 29, 2014