What is this important?

So many times, people with ADHD or their family members have told me that they felt relieved about receiving confirmation that they have ADHD. They have faced many struggles with poor concentration, overactivity, and impulsivity throughout their lives, and now they know why. They are also happy to know that there are medications, such as stimulant medications, that can help them manage these symptoms.

And then so often they ask me: ‘Doctor, is this medication going to help me?’. ‘Well, we can definitely say that stimulant medication generally works, but to date we cannot predict in advance who is going to respond.’ This unfortunately leaves individuals and their families with the difficult decision as to whether try the medication, and maybe experience side effects, or not. They may also need to try more than one medication before finding the right one, which is not ideal because it takes time and may delay them getting better.

In our research, we aim to change this.

What we did

We wanted to understand whether brain characteristics can help us understand in advance who is going to respond to methylphenidate, a very common stimulant medication for ADHD. We recruited 60 adults with ADHD and used magnetic resonance imaging to take images of their brain before giving them the medication. To better interpret our findings, we also recruited 20 people without ADHD.

We used an advanced imaging technique known as ‘tractography’ to identify two main brain connections affected in ADHD. These are like paths that connect brain regions supporting cognitive functions such as attention and inhibition. We then tested whether the characteristics of these connections, such as their size or organization, before starting treatment could tell us about the probability of responding to two months of treatment. Finally, to see if we could be more accurate in determining this probability, we combined information on brain connections with other individual characteristics, such as symptom severity and performance at cognitive tests measuring attention and inhibition.

Key findings

We observed that, as a group, individuals with ADHD that do not respond to methylphenidate have a smaller left dorsal attentive network as compared to those who respond and people without ADHD. This brain connection is important to voluntarily direct our attention, thus the fact that its size is linked to how well someone with ADHD responds to medication makes sense. This characteristic had a fair ability to tell us whether an individual would respond to the medication when considered alone and a good ability when combined with other individual characteristics, such as better performance at the cognitive tests.

What next?

Our study takes an important first step toward personalized ADHD treatment in adults. While there is still much work ahead, with further confirmation in independent studies and clinical trials needed, our findings could pave the way for tailored treatments that address the unique needs of each individual with ADHD. This kind of research opens the door to a more promising future for those living with ADHD.

If you want to know more, you can read the full-text here: https://www.nature.com/articles/s41398-023-02598-w

Thanks

A special thanks to all the participants  who took part in this research!