Prior research had hinted that ADHD drugs might raise the risk of suicidal behavior, according to the authors of the new report. However, they believe that the findings of those studies were questionable due to their studies' small size or the methods used.
The new study, led by Henrik Larsson of the Karolinska Institute in Stockholm, Sweden, included all of the nearly 38,000 people in Sweden diagnosed with ADHD between 1960 and 1996.
Larsson's team tracked their rates of suicidal behaviors between 2006 through 2009, at times when they were taking ADHD drugs or not taking the medications.
The result: The study found no evidence that taking ADHD drugs raised the risk of suicide attempts or suicide, the investigators reported online June 18 in the BMJ.
"Our work in several ways shows that most likely there is no link between treatment with ADHD drugs and an increased risk of suicide attempts or suicide. The results rather indicate that ADHD drugs may have a protective effect," Larsson said in an institute news release.
The authors said a particular strength of their study was that they compared patients when they were and were not taking ADHD drugs. Larsson noted that many population-based studies on risks related to particular medications "fail to adjust for the differences between individuals who take the drugs and those who do not. This is a critical limitation given that the individuals on medication are usually more severely ill than the others."
One U.S. expert in the care of people with ADHD said the study gives valuable reassurance to patients.
"This rigorous study is a real contribution to the field and should be recognized as such by laypeople and the scientific community alike," said Dr. Aaron Krasner, service chief of the Adolescent Transitional Living Program at Silver Hill Hospital in New Canaan, Conn.
He said the study was well designed, both because of its very large sample size and the fact that it tracked suicidal behaviors when individual patients were either on or off the medications.
Krasner added that the study findings "make intuitive clinical sense to the average practitioner... We know that our treatments work and should not be withheld from patients unnecessarily, provided adequate monitoring and assessment is ensured."
The U.S. National Institute of Mental Health has more about attention-deficit/hyperactivity disorder.