Dr Elizabeth O’Nions and Professor Joshua Stott on ADHD and life expectancy

ADHD is a neurodevelopmental condition characterised by symptoms of inattention and hyperactivity/impulsivity. Many people with ADHD have problems that fall into both categories, but this is not always the case. There is no single cause of ADHD and research suggests it involves genetic, environmental, and neurological factors. Whilst commonly thought of as a childhood disorder, there has been a significant rise in ADHD diagnoses in the UK, with the relative increase largest among adults.

Effective management of ADHD often includes a combination behavioural therapy, medication and lifestyle adjustments. However, if left untreated, people with ADHD can struggle with significant disruption to their personal and professional lives.

In this Q&A, we spoke to Dr Elizabeth O’Nions and Professor Joshua Stott who recently published a paper finding that adults diagnosed with ADHD may have reduced life expectancies.

How does ADHD impact the brain’s ability to regulate attention and focus?

Joshua: What an ADHD diagnosis requires is symptoms relating to a lack of focus and/or impulsivity and hyperactivity. Those symptoms need to have been going on for at least six months, be affecting various areas of life and to have been something present since before the age of seven. Some people will experience all the symptoms whereas others will just have a few.

Often when you meet someone with ADHD, they may find it difficult to keep still or may interrupt someone when they are speaking because it is hard to stop themselves ‘getting the thought out’, or struggle to pay attention to mundane tasks while being able to maintain hyperfocus on tasks they are really interested in.

What are the most common symptoms of ADHD in adults, and how do they differ from those in children?

Joshua: Symptoms in adults and children tend to be quite similar, however, for those who struggle with impulsivity, research suggests that addiction can become an issue in adult life. This might be partly to do with the fact that people with ADHD struggle to gain the same amount of dopamine signals to their brain when compared to people who do not have ADHD. In order to gain that dopamine hit, they may participate in potentially harmful activities; and their struggles with impulsivity may make it hard for them to stop doing this.

What are some of the challenges of diagnosing and treating adults with ADHD?

Elizabeth: ADHD is a relatively recent diagnosis so if you are about 40 years old or older, people probably weren’t wondering if you had ADHD when you were a child. Diagnoses are mostly made in children, and awareness of ADHD in adults is quite poor. This means that many adults who might meet criteria for ADHD don’t know that they have it. 

Surveys conducted internationally suggest that 2.8% of the adult population have ADHD. Only 0.32% of adults had an ADHD diagnosis in our UK study, meaning 8 out of 9 UK adults with ADHD are undiagnosed and are therefore unable to access support and treatment.

We know that adults with ADHD often experienced social exclusion throughout their lives - for example, because the education system is not designed to accommodate their needs, leading to educational under-attainment and under-employment. They may have developed self-regulation strategies that are harmful to health like smoking, substance use, or over-eating.

Adults with ADHD are also more likely to have experienced more stressful life events on average than the general population, with adverse impacts on mental health and physical health. Evidence from England suggests that adults with ADHD are presenting to services, but services are not equipped to support them: a previous (2014) national survey found that nearly 8% of people who screened positive for ADHD had requested a particular mental health treatment in the past 12 months but had not received it, compared to 1% of those who did not screen positive.

In your recent study, you found a reduced life expectancy for those with ADHD, compared to those without. The average reduction was larger for women than men, do you have any insight as to why this may be?

Joshua: We looked at a representative sample of GP records from people across the UK and, using the life expectancy prediction methods of the Office of National Statistics, we compared the life expectancy of people with ADHD to those without it.

We found that men with ADHD were expected to live 6.7 years less than those without it. The life expectancy of women with ADHD, meanwhile, was 8.64 years shorter than their counterparts.

We don’t know why this discrepancy exists between genders, but perhaps because ADHD is viewed stereotypically as a male condition and it’s seen as something that is less common in women there may not be the same level of reasonable adjustments made for women as there is with men. However, that is purely a hypothesis as there is no data on that.

What are some of the modifiable risk factors that contribute to the reduced life expectancy in adults with ADHD?

Elizabeth: We don’t believe that a shorter life expectancy is inherent to ADHD, but rather a consequence of what happens when people with ADHD don’t receive the right support and treatment at the right time. 

We didn’t look at causes of death in our study, so from our work, we don’t know what the factors are. 

Based on wider evidence, we think that some modifiable risk factors could be behaviours often used to self-regulate or self-manage ADHD, such as smoking, over-eating, substance use, and risk taking. We know that ADHD symptoms also contribute to social exclusion, financial difficulties, and unemployment, harming mental health and self-esteem. They can also make it difficult for people to remember to take medications consistently, book and attend appointments regularly, and engage in positive health behaviours. Making services more readily accessible and providing support for physical and mental health tailored to the needs of people with ADHD could make a big difference. 

How can healthcare providers better support adults with ADHD to potentially improve their life expectancy?

Elizabeth: We need more evidence to determine what the best approaches are. My belief is that ADHD-specific support and treatment for physical and mental health support needs could address some of the barriers that prevent adults with ADHD engaging with services and accessing help when they need it.