Clinical observation has long shown that individuals with attention-deficit/ hyperactivity disorder (ADHD) often have emotional problems, such as chaotic emotional responses, anxiety and depression.

Yet the link between ADHD and impaired emotional regulation has not been identified, even though theories have proposed that both conditions are rooted in a dysfunction in how the brain processes information.

Now a new Swedish study finds that the brains of people with ADHD and those with emotional instability disorders (borderline personality disorder, antisocial personality disorder and conduct disorder in children) may exhibit similar changes in overlapping areas, suggesting the two types of conditions should be seen as related.

For the study, researchers at Karolinska Institutet in Sweden observed more than 1,000 adolescents to study the brain images of those with ADHD and emotional instability traits (conduct disorder). The findings, published in the journal Molecular Psychiatry, may lead to a broader treatment for both conditions.

“We can call them sibling conditions, since they both involve partly overlapping underlying brain mechanisms, and therefore attention should be paid to both dimensions during diagnosis,” said Dr. Predrag Petrovic, associate professor at the Department of Clinical Neuroscience at Karolinska Institutet and consultant psychiatrist at North Stockholm Psychiatry.

Structural magnetic resonance imaging (MRI) was able to demonstrate how both ADHD and conduct disorder traits in adolescents manifested themselves in the form of reduced brain volume and surface area in parts of the frontal lobe and nearby regions.

The affected parts of the brain were generally overlapping, but the researchers also found changes that were specifically related to ADHD symptoms or symptoms seen in conduct disorder. The study also included behavioral experiments that demonstrated both conditions.

“These results are important not least for the patients with emotional instability, since in many cases they are treated with scepticism and feel frustrated at not being taken seriously,” said Petrovic.

“We now show that this is related to changes in the brain that resemble those that have been observed in patients with ADHD, which can lead to a broader understanding and better diagnosis.”

The research was part of the IMAGEN-project, an EU-funded collaboration amongst several European countries that aims to better understand how the brain and behavior develop.

The researchers hope the new findings will not only lead to better diagnoses but also to better treatments, where people with an ADHD diagnosis can receive special therapy to help them better handle their emotions.

“We also need to do more research to understand if central stimulant medication used for ADHD can also produce positive results for people with emotional instability disorders,” Petrovic said.

Source: Karolinska Institutet