The research was carried out by Dr Vibhore Prasad and other researchers working at the University of Nottingham and King's College London, funded by the Academy of Medical Sciences.

Dr Prasad, who is now an NIHR East Midlands Scholar, associated with the University of Nottingham, a visiting Lecturer at King's College London and a GP in Nottinghamshire, undertook the research after his previous work indicated ADHD diagnosis is often missed and delayed in the UK.

We know that children with ADHD often face long delays in diagnosis. We didn't know, until now, that they seek help from the healthcare services twice as often as children without ADHD in the run up to diagnosis. Our findings demonstrate the need for further research so we can identify children with ADHD earlier to get them effective help.

The results are significant because we know that identifying ADHD earlier can lead to effective treatment, including talking treatments and medicines, which can prevent a range of serious harms to young people and future adults."

Dr Vibhore Prasad, University of Nottingham

The study looked at medical records of children and young people aged between four and 17 years old from the Clinical Practice Research Datalink, a primary care database containing the records of around 15 million people from 730 GP practices and representing seven per cent of the population of the UK. The findings were based on around half of the patients from England who also had linked hospital medical records.

The research focused on the reasons why children see their GP, receive prescriptions from the GP, attend hospital for overnight admissions and have operations in hospital. It showed that children with ADHD make twice as much use of all these services in the two years before diagnosis compared to children without ADHD.

Professor Edmund Sonuga-Barke (senior author), NIHR Maudsley Biomedical Research Centre, and Dr Johnny Downs, Consultant Child and Adolescent Psychiatrist (co-author) based at King's College London, said: "Dr Prasad's study provides a powerful reminder of both the physical and mental health difficulties that young people have to confront in the years leading up to an ADHD diagnosis. At this point, we cannot be certain that earlier access to ADHD assessment and treatment would alleviate all these difficulties. However, Dr Prasad's work does highlight that young people who have suspected ADHD are already a vulnerable group and may benefit from coordinated multi-disciplinary care that can provide holistic support whilst they are waiting for specialist mental health services."

Michele Reilly, Lead of Lambeth ADHD Support Group, said: "Dr Vibhore visited the Lambeth ADHD Support Group on several occasions in the process of his research, and has diligently captured the voices of the parents and carers of young people with ADHD. This attention to detail and genuine interest in the welfare of families, has provided valuable insights into how families navigate the healthcare system and engage with their GP prior to an ADHD diagnosis. The identification of patterns of GP interaction for families with a child with ADHD offers valuable insights for both families themselves and professionals."

Children and young people with ADHD regularly see healthcare professionals but guidance from organisations such as the National Institute for Health and Care Excellence (NICE) and the American Academy of Pediatrics does not currently detail how to detect ADHD earlier. Many parents or carers report needing to know about ADHD in order for the professionals to consider this as a diagnosis.

The researchers say this study shows that more should be done to develop and test interventions to identify ADHD earlier in primary care. There is also a need to urgently review how the health services cater for young people with undiagnosed ADHD.

Dr Tony Lloyd, CEO of the ADHD Foundation Neurodiversity Charity, said: "This is groundbreaking research that demonstrates to the Department of Health, NHS UK & local NHS Commissioners, that ADHD should not be trivialised and reduced to core symptoms of hyperactivity, impulsivity and inattention. Undiagnosed untreated ADHD is now proven to result in double the number of health care appointments and procedures children using the NHS for other avoidable health problems and accidents."