It was the summer of 2014, I was deep into A-level revision and my mornings all began the same way.After breakfast, I would take two small, white pills. By the time I had showered, my heart would be beating so fast it felt like it was going to burst out of my chest.But I’d ignore this and sit at my desk, where I’d often stay for four or five hours at a time, not even getting up to go to the toilet or eat.The pills were Ritalin, a stimulant ADHD medication I had been prescribed two years previously.Attention deficit hyperactivity disorder, or ADHD, is characterised by an inability to concentrate or stay still for extended periods.Previously it was considered a rare condition. However, there are now 750,000 children and 1.5million adults diagnosed with ADHD in the UK.As a result, there are a record number of patients taking ADHD medicines, according to Oxford University research published in January.Prescriptions for these tablets – which increase heart rate and blood pressure – have risen across all age groups, including in older adults and children as young as three.But in recent years various studies have called into question the safety of these medicines.Last week, the charity Cardiac Risk In The Young warned that ADHD patients are at risk of deadly heart complications. The charity argued that all NHS patients placed on the tablets should be screened for heart defects – that affect one in 300 people – first. Ethan Ennals in 2012... I took Ritalin for two years as a teenager, he writes. The tablets left me anxious and anti-socialThe warning comes a year after the death of 28-year-old Jacob Wooderson, who passed away after taking another ADHD called Elvanse.The finance worker suffered sudden arrhythmic death syndrome – when a young and seemingly healthy person dies of cardiac arrest – shortly after his dose was increased.At the time, coroner Sarah Bourke called on the Government to launch an inquiry into the tablet’s safety, which is ‘increasingly being prescribed in the NHS’. However, no such inquiry was ever commenced.So why was I on the pills?As a child I’d been quiet and well-behaved. However, at 14 things changed drastically when my parents’ divorce threw home life into chaos.I would skip school, argue with teachers and disrupt lessons. When I could be convinced to sit still, my mind wandered and I’d spend more time doodling than doing any work.Six months before my GCSEs, I was on course to fail them all. In desperation, my parents took me to see a psychiatrist who diagnosed me with ADHD and prescribed Ritalin.The idea was to take them every day, but I quickly found that was impossible. When I took them at school, my concentration on tasks would improve, but I also found it challenging to talk or write essays. It was as though the pills dulled my creativity. Ethan says his experience led him to believe that many people currently taking ADHD tablets should not be on them