No increase in serious heart risks for adults taking ADHD drugs

By Sophie Ramsey

BMJ Group News

What do we know already?

Attention deficit hyperactivity disorder (ADHD) is a condition often associated with children, but adults can also have ADHD. It can cause symptoms such as impulsive behaviour and difficulty concentrating.

To manage these symptoms, many people take medications, including methylphenidate, dexamfetamine and other drugs, which help people concentrate and feel calmer. Some people may take a drug called atomoxetine to help some of the other symptoms of ADHD.

These treatments can work well, but there is concern that they make people more likely to have serious heart and circulation problems, such as heart attacks, strokes and sudden cardiac death (when the heart suddenly stops pumping).

This concern stems from previous studies that have found that these drugs can raise a person’s heart rate and blood pressure, which might increase the risk of these problems.

Earlier this year the results of a large study showed there was no increase in serious heart and circulation problems among children and teenagers taking these drugs. This study in adults seems to show similar results.

The researchers compared more than 150,000 adults aged 25 to 64 who were taking ADHD drugs with more than 443,000 adults not taking these drugs. People were studied for different lengths of time, ranging from less than a year to more than 13 years. The researchers could then see if people who took ADHD drugs were more likely to have heart or circulation problems than those who did not.

What does the new study say?

Using medical and death records, the researchers recorded 1357 heart attacks, 575 strokes and 296 cases of sudden cardiac death. After accounting for things that can affect a person’s risk of these problems (such as their age, and whether they have heart disease or diabetes), they found that people who took ADHD medicines were no more likely to have had one of these problems than people who weren’t taking these drugs. In fact, people taking these medicines actually had a 17% lower risk than people who weren’t taking ADHD drugs.

The researchers think the lower risk is because of ‘healthy-user bias’. This means that people managing their ADHD with medications may have been better about managing their health in general. To account for this, the researchers also compared people who previously took ADHD medicines with those currently taking them, assuming that these groups would be similarly attentive to their health. In this comparison, the groups had nearly identical risks of heart attacks, strokes and sudden cardiac death.

The researchers calculated that even the highest estimate of additional risk from taking ADHD medications would mean there would be less than one extra heart attack or stroke for every thousand patients taking the drugs for one year.