Autistic people and people with attention deficit hyperactivity disorder (ADHD) often experience anxiety and depression. When these conditions occur together, though – as they often do – it can be hard to unpick which one is contributing the most to poor mental health. Our latest study aimed to find out.
We discovered that people with more ADHD personality traits were more likely to experience common mental health problems like depression and anxiety than people with more autistic traits. This is the first study, as far as we are aware, which shows that people with ADHD are more likely to have poor mental health than autistic people.
To conduct our study, we asked over 500 adults in the UK to complete questionnaires measuring autistic and ADHD traits. We also asked them to complete standard questionnaires for depression and anxiety.
This is known as a “trait approach” to autism and ADHD. It involves looking at people’s individual characteristics rather than their diagnoses. This allows us to indirectly understand how much different conditions overlap.
We then used statistical tests to measure the strength of the relationship between autistic traits and mental health problems and compared this to the link between ADHD traits and poor mental health.
Our results showed both ADHD and autistic personality traits could predict the severity of a person’s anxiety and symptoms of depression. But what was new was that people were more likely to experience these symptoms if they had many ADHD traits compared with those who had a lot of autistic traits. We found that the link between ADHD and poor mental health was around three times stronger than the link between poor mental health and autism.
These results were replicated in computerised simulations with a 100% “reproducibility rate”. In other words, ADHD traits are almost certainly more linked to poor mental health than autistic traits in the UK population.
Our study highlights a clear link between ADHD and common mental health problems in adults. The next step is to examine the factors that might be driving this relationship. Scientists know that the genes linked to ADHD are also linked with certain mental health conditions, such as depression. People with ADHD are also more likely to experience stressful life events, which can lead to mental health difficulties.
It will now be important to look at how environmental and social cognitive factors (such as how well people understand others) may influence mental health in this group. This research is crucial for identifying people who are most at risk of poor mental health. Knowing what signs to look out for could let doctors intervene early, before people become severely anxious or depressed.
But to better understand the links between ADHD and mental health, and which support approaches may be most effective for this group, more funding needs to be invested in research. Funding for ADHD research is lacking in comparison to other conditions, such as autism. Yet, considering that almost 30% of autistic people also have ADHD, it’s clear that greater funding into this research area could have far-reaching benefits for many people.
Luca Hargitai receives funding from the Economic and Social Research Council.
Lucy Anne Livingston has received funding from the UKRI Medical Research Council and The Waterloo Foundation.
Punit Shah receives or has received funding from the UKRI Medical Research Council and the Economic and Social Research Council.