A group of UK Attention Deficit Hyperactivity Disorder (ADHD) experts, including a senior consultant from the South Eastern Trust, are warning that delays in spotting ADHD in children can cause serious damage to their mental health.
It comes as they call for an urgent review of mental health policies for children with the disorder.
The group have issued a stark warning that young people in the UK with the common neurodevelopmental disorder remain at serious risk of social and mental health harm due to some of the longest and most complicated delays to diagnosis anywhere in Europe.
It is estimated that there are currently in the region of 40,000 people with ADHD in Northern Ireland.
A report launched on Friday highlights that nearly a third (28%) of children with ADHD can wait two or more years before receiving a diagnosis in the UK, despite the availability of several effective management strategies for the condition.
It also reveals that 51% of cases experienced a lack of recognition for ADHD as a real condition from those on the front lines of helping children, including GPs, specialists and school staff.
The report warns that if ignored, ADHD brings consequences that can range from school exclusion and increased risk of anxiety and depression through to self-harm and even suicide.
Attention deficit hyperactivity disorder (ADHD) is a neurodevelopmental disorder caused by structural and functional abnormalities in the brain that result in a group of behavioural symptoms including inattentiveness, hyperactivity and impulsiveness.
Dr Matthew McConkey, Consultant Paediatrician at the Lagan Valley Hospital in Lisburn believes much more needs to be done.
He said: "ADHD remains chronically underdiagnosed and access to services and treatment in the UK is woefully inconsistent."
Dr McConkey added: "Long-term solutions must be put in place by the NHS to ensure no child falls through the gaps - this includes improving the patient journey to diagnosis and challenging the stigma prevalent throughout the healthcare community."
The report includes results from a survey of 104 adults or parents of children diagnosed with ADHD across the UK.