The benefits of taking drugs for attention deficit hyperactivity disorder outweigh the impact of increases in blood pressure and heart rate, according to a new study.
An international team of researchers led by scientists from the University of Southampton found the majority of children taking ADHD medication experienced small increases in blood pressure and pulse rates, but that the drugs had “overall small effects”. They said the study’s findings highlighted the need for “careful monitoring”.
Prof Samuele Cortese, the senior lead author of the study, from the University of Southampton, said the risks and benefits of taking any medication had to be assessed together, but for ADHD drugs the risk-benefit ratio was “reassuring”.
“We found an overall small increase in blood pressure and pulse for the majority of children taking ADHD medications,” he said. “Other studies show clear benefits in terms of reductions in mortality risk and improvement in academic functions, as well as a small increased risk of hypertension, but not other cardiovascular diseases. Overall, the risk-benefit ratio is reassuring for people taking ADHD medications.”
About 3 to 4% of adults and 5% of children in the UK are believed to have ADHD, a neurodevelopmental disorder with symptoms including impulsiveness, disorganisation and difficulty focusing, according to the National Institute for Health and Care Excellence (Nice).
Doctors can prescribe stimulants, such as methylphenidate, of which the best-known brand is Ritalin. Other stimulant medications used to treat ADHD include lisdexamfetamine and dexamfetamine. Non-stimulant drugs include atomoxetine, an sNRI (selective norepinephrine reuptake inhibitor), and guanfacine.
The study of children, adolescents and adults states: “There is uncertainty regarding whether medications that are used for the treatment of ADHD may lead to cardiovascular diseases, and concerns remain around their cardiovascular safety.” It found all ADHD medications were associated with small increases of blood pressure and heart rate, except guanfacine, which led to decreased blood pressure and heart rate.
There were no significant differences regarding the impact on blood pressure and heart rate between stimulants (including methylphenidate and amphetamine) and non-stimulants (atomoxetine and viloxazine). The researchers advised people with existing heart conditions to discuss the side effects of ADHD medications with a specialist cardiologist before starting treatment.
Dr Ulrich Müller-Sedgwick, a consultant psychiatrist and expert on ADHD, said most clinicians prescribing ADHD medication understood the cardiovascular risks and followed Nice guidelines for monitoring blood pressure, pulse and weight. “We need more detailed guidelines for scenarios when ADHD medication needs to be adjusted or stopped,” he said.
Last year, a thinktank warned that the NHS was experiencing an “avalanche of need” over autism and ADHD, and said the system in place to cope with surging demand for assessments and treatments was “obsolete”. The number of prescriptions issued in England for ADHD medication has risen by 18% year on year since the pandemic, with the biggest rise in London.
Dr Tony Lord, a former chief executive of the ADHD Foundation, said the long-term benefits of ADHD medication were well established, and included a reduced risk of anxiety and depression, eating disorders, harm from smoking, improved educational outcomes and economic independence.
“Sadly ignorance about ADHD medications persists – a throwback to the 80s and 90s when ADHD medications were mistakenly viewed as a morality pill that made naughty, fidgety disruptive children behave – which of course it is not,” he said.
“It is simply a cognitive enhancer that improves information processing, inhibits distractions, improves focus, planning and prioritising, self monitoring and reduces impulsivity of thought and action.”