By Imogen Howse via SWNS Medication given to young adults with attention deficit hyperactivity disorder ( ADHD ) may increase their risk of heart damage, a new study has warned. Researchers from the
United States discovered that those prescribed stimulants for ADHD were ‘significantly’ more likely to develop cardiomyopathy, (weakened heart muscle), than those who were not prescribed any medication. Prescriptions of drugs such as Adderall and Ritalin led to a 17 percent increased risk of cardiomyopathy after a year, and a 57 percent increased risk of cardiomyopathy after eight years. However, the team said the overall risk of cardiomyopathy remained low, even when stimulants were used over a long period. “This means our findings do not necessarily point to a need for clinicians to change their approach to screening patients or prescribing stimulants,” said the study’s lead author Pauline Gerard, a medical student at the University of Colorado. ADHD is one of the most common neurodevelopmental disorders, affecting around ten percent of
American children and five percent of
UK children. It is typically treated with behavioral therapy, but this can be combined with stimulant medications that help control ADHD behaviors that affect the patient’s daily life. Scientists have previously assessed the safety of these stimulants and found no evidence of harm to the heart, but their studies have only focused on the first year or two of use. Gerard therefore wanted to assess stimulants' potential to cause harm over a longer time period, given that most people with ADHD start taking stimulants as children and continue this into adulthood. She particularly wanted to examine any relation to cardiomyopathy, a condition that involves the weakening of the heart muscle. This causes a person to tire easily and limits their ability to perform daily tasks. The research team from the University of
Colorado gathered participants aged between 20 and 40 from across 80 hospitals in the US, all of whom had been diagnosed with ADHD. From this group, they paired each person who had been prescribed stimulants with a person who had not, making sure the pairs were as similar as possible in all other aspects, such as age, sex, and other health conditions. Overall, they created 12,759 pairs whom they followed for at least a decade. Results of the study, published by the American College of Cardiology , revealed that people prescribed stimulants were significantly more likely to develop cardiomyopathy throughout the ten-year period. The gap increased each year except for the last two when it narrowed slightly. However, despite this difference, the overall prevalence of cardiomyopathy remained low among both groups. After being prescribed stimulants for 10 years, 0.72 percent of patients developed cardiomyopathy, compared with 0.53 percent of those who were not prescribed stimulants. Gerard said: “The longer you leave patients on these medications, the more likely they are to develop cardiomyopathy, but the risk of that is still very low. “To put the numbers into context, you can have almost 2,000 patients on these medications for a year and you might only cause one of them to have a cardiomyopathy that they otherwise would not have had. “But, if you leave them on it for 10 years, one in 500 will have that happen.” Gerard said that the findings do not suggest that ‘aggressive’ testing for risk of heart damage is warranted before stimulant prescriptions, given that the potential benefits of testing must be balanced against the potential risks. She also argued that the study does not indicate a need to stop prescribing these medications. “I don’t think this is a reason to stop prescribing these medications,” Gerard said. “There’s very little increased risk of these medications over the long term; it’s a real risk, but it’s small.” She added that in future studies, she would like to identify subgroups who may be at greater risk of cardiomyopathy – and therefore may benefit from screening – and compare the differences between different types of ADHD medications .