Patients with ADHD (Attention-Deficit Hyperactivity Disorder) are 60-90 percent more likely to miss appointments with their doctors, compared to the general population, according to the first study to examine this issue within general medical practice.

Multiple missed doctors’ appointments, referred to as ‘missingness’, are a significant concern for patient care. Previous research by the same team of researchers has shown that missing appointments is linked to a greatly increased risk of illness and early death.

The new three-year study from the Universities of Bath, Glasgow, Aberdeen and Copenhagen, analysed data from 136 GP practices in Scotland to establish the prevalence of recorded ADHD and assess whether it is associated with an increased risk of missing scheduled appointments. This included over 1,400 patients with an ADHD diagnosis.

The researchers found that for children and adolescents with recorded ADHD, 21 percent missed at least one face to face appointment annually, compared to 10 percent of people without ADHD, and 8 percent missed two or more annually.

In adults, 38 percent missed at least one appointment annually, versus 23 percent without ADHD, and 16 per cent missed two or more.

Professor David Ellis, from the University of Bath’s School of Management, said: “Missed appointments can have short and long-term consequences for society as a whole, but crucially we know multiple misses are a red flag for poor patient outcomes. It can mean missed opportunities for providing care where it is often most needed.

“Our study showed patients with ADHD have higher rates of both mental and physical health problems than those without the condition, so multiple missed appointments will take their toll. Missing appointments may also be playing a role in delayed diagnosis and treatment of ADHD.”

ADHD is relatively common, with an estimated prevalence of 2-5 percent of the population, but is often not diagnosed formally. Symptoms usually persist throughout life but are commonly interpreted as indicating diagnoses other than ADHD.

In the sample of Scottish patients, from September 2013-2016, the recorded prevalence of ADHD was 0.3 percent, with 84 percent of all recorded diagnoses being in patients under 35 years of age. This apparently low prevalence is comparable to other studies using data derived from medical records.

Professor Andrea Williamson, from the University of Glasgow, said: “We often hear criticism of people who miss GP appointments, but patients with ADHD may struggle to attend due to cognitive impairments associated with their condition. These impairments can affect their ability to schedule and remember appointments. Understanding and addressing ‘missingness’ is a complex issue that requires research and targeted interventions in health care to improve outcomes.”

The researchers hope that the study will lead to more awareness of the challenges facing the diagnosis and treatment of ADHD and that health services will look to work with patients, care providers and technology developers to improve access to appointments.

Professor Philip Wilson, from the Universities of Aberdeen and Copenhagen, said: “ADHD is associated with other brain conditions such as dyslexia which can lead to problems with appointments. It is also associated with behaviours which increase health risks. It is therefore particularly important that we find ways to allow ADHD patients to engage effectively with health services.”

The study is funded by the Chief Scientist Office, Scottish Government (reference CZH/4/1118).

Attention-Deficit/Hyperactivity Disorder and serial missed appointments in general practice is published in PLOS Mental Health.