People with attention deficit hyperactivity disorder (ADHD) may have an increased risk of suicide, according to a new study. Researchers also found an increased risk of suicide in the parents and siblings of people with ADHD.
The findings suggest that genetics may link ADHD and suicidal behavior, the researchers said.
"Our study is the first, to our knowledge, to show that ADHD and suicidal behavior share genetic risk factors," the researchers wrote in their article, published today (June 25) in the journal JAMA Psychiatry. Previous studies showed that genetic influences affect people's risk of both ADHD and suicide, the researchers noted. [5 Myths About Suicide, Debunked]
The results suggest it could be important to reach people with ADHD and their relatives with efforts aimed at suicide screening and prevention, the researchers said.
In the study, researchers at the Karolinska Institutet in Sweden compared suicide rates of patients with ADHD to suicide rates of people without the disorder, using data from the country's national database. The researchers looked at nearly 52,000 patients with ADHD, about a third of whom also had another psychiatric disorder, as well as about 260,000 people without ADHD.
Suicide rates have increased in recent years, but the act is still uncommon. The researchers found that, of the study participants without ADHD, 1.3 percent attempted suicide and 0.02 percent completed suicide.
However, people in the study with ADHD had a higher risk of suicide: 9.4 percent attempted suicide, and 0.2 percent committed suicide.
Parents and siblings of people with ADHD also had an increased risk of suicide, according to the study. The researchers found that 6.6 percent of the parents of people with ADHD attempted suicide, and 0.7 percent completed suicide. Among the siblings, 3.4 percent attempted suicide, and 0.2 percent committed suicide.
The risk was much lower among more distantly related family members such as cousins, according to the study.
The researchers said the elevated risk in close family members could mean that ADHD and suicidal behavior share a genetic factor, and the elevated risk could be passed from parents to kids.
Previous studies of ADHD and suicide risk have primarily been done in small groups of people, the researchers said.
Doctors already know that people with ADHD are more likely to have other mental health disorders, such as schizophrenia and depression, the researchers said. Previous research has suggested that people with ADHD may have a higher suicide risk because they may have more than one mental health disorder.
However, the researchers adjusted their data to exclude people with multiple psychiatric disorders; results showed that the risk of suicide among ADHD patients remained well above that for people without ADHD.
The researchers acknowledged that environmental factors like abuse and even ADHD medication could also contribute to the high suicide risk among ADHD patients, and said that future research should examine the influence of these factors.