Researcher’s Journal: How my ADHD journey shaped my PhD

In this blog, PhD student Isabella Barclay discusses their recently published paper on ADHD diagnosis, exploring why some individuals receive a diagnosis later than others and how sex differences play a role in missed or delayed diagnoses. They share their personal motivations, key findings, and next steps in their research journey.  

My name is Isabella Barclay, and I am a third and final year PhD student in the Wolfson Centre for Young People’s Mental Health. My main area of interest is attention deficit hyperactivity disorder (ADHD), specifically sex differences and late or missed ADHD diagnosis. This stems from my own lived experience, combined with an academic history of studying neuroscience.

I received my ADHD diagnosis four years ago at the age of 22, after struggling for many years.  This made me want to pursue a PhD in this area as I know firsthand the struggles associated with a late diagnosis of ADHD. Learning how it disproportionately affects girls and women made me want to investigate this further.

I’ve recently published a paper on the topic. This is my first ever published paper, so I’m really excited about it and proud that it is now out in the world! It addresses the core questions of my PhD – why are some people diagnosed with ADHD later than others, or not at all despite having ADHD symptoms? I also wanted to find out what difference a person’s sex makes in their likelihood of being diagnosed with ADHD.

This is such an important topic area when you consider that many people aren’t diagnosed with ADHD until late adolescence or even adulthood and therefore haven’t had the additional help (for example, in school or from their friends) that could have significantly improved their outcomes.

This is especially an issue for girls and women, as they are more likely to be diagnosed later. The aim of my paper was to further investigate why some people are diagnosed later or not at all and to gather some answers as to why girls and women are so disproportionately affected. This is important because understanding the characteristics that may be linked with an individual being less likely to be diagnosed can help clinicians identify those who might otherwise be overlooked.

I looked at these questions in a large sample of young people across the UK, who were part of the Millenium Cohort Study, a data collection study that follows the development of participants since they were born. We compared a range of factors between those who had an ADHD diagnosis at different ages, as well as those whose parents reported high ADHD symptoms but they never received a diagnosis.

We were interested in how these groups differed on various behavioural and emotional scales, cognition, autism diagnosis, physical activity and engagement in hobbies. I discovered that those who received an earlier ADHD diagnosis were more likely to have lower cognition, lower prosocial skills (sharing and caring behaviours) and more behavioural (how disruptive they are) and emotional difficulties (symptoms of anxiety and depression, and dysregulation of emotions) compared to those diagnosed later. A similar pattern, plus a diagnosis of autism and less physical activity, appeared when investigating why some people had recognised ADHD while others had unrecognised ADHD (symptoms without a diagnosis).

This suggests that if a young person displays other difficulties on top of their ADHD, they are more likely to be diagnosed with ADHD, and earlier, than those without these additional difficulties. Therefore, it highlights the need for any young person displaying ADHD symptoms, regardless of cognitive or prosocial ability, or other diagnoses, to be considered for ADHD referral.

I also investigated sex differences in the comparison between recognised and unrecognised ADHD. Emotional dysregulation (difficulty controlling emotions and reactions) was the only significant difference. Boys with recognised ADHD were more likely to have more emotional regulation difficulties compared to their unrecognised peers, but this difference was not seen in recognised vs unrecognised girls. This is an interesting discovery and suggests that societal expectations may play a role in diagnosis likelihood. Boys with greater emotional dysregulation may be more likely to be identified as needing referral for a condition such as ADHD, while girls with similar difficulties might be overlooked.

Now that this paper is finished and published, my next step is to build on this research using different data. I have access to another great dataset from Sweden that I plan to use to explore similar questions but with more specific data, as well as examining some other interesting factors. This is what I am currently focusing on, and I am really looking forward to the results!

Isabella’s paper, “Investigating the reasons behind a later or missed diagnosis of attention-deficit/hyperactivity disorder in young people: A population cohort study” is published on JCPP Advances and available to view online.

Thank you, Isabella, for writing this blog for us!

Keen to hear more from our researchers and PhD students? 

Read about Abbey’s experiences in the first and second year of her PhD, along with her blog reflecting on what type of researcher she is.