How Does ADHD Affect Emotion Recognition in the Brain?

What you need to know

• People with ADHD showed less brain activity in regions involved in processing emotions when viewing emotional faces compared to those without ADHD
• The connection between two key brain regions involved in emotion processing worked differently in those with ADHD
• These brain differences may help explain why some people with ADHD have difficulty recognizing emotions in others

Background on ADHD and Emotion Recognition

Attention-deficit/hyperactivity disorder (ADHD) is a common neurodevelopmental disorder that affects about 5% of children and 2.5% of adults. While the core symptoms involve problems with attention, hyperactivity, and impulsivity, many people with ADHD also struggle with recognizing and regulating emotions.

Being able to accurately recognize emotions in other people is an important skill for social interactions and relationships. Some studies have found that individuals with ADHD tend to be less accurate at identifying emotions from facial expressions. This difficulty with emotion recognition may contribute to some of the social challenges and emotional regulation problems that often occur with ADHD.

To better understand the brain processes involved, researchers used functional magnetic resonance imaging (fMRI) to look at brain activity while adolescents and young adults with and without ADHD performed an emotion recognition task. The study aimed to identify differences in how the brains of people with ADHD respond when viewing emotional faces compared to those without ADHD.

How the Study Worked

The researchers recruited 61 participants with ADHD and 51 participants without ADHD, ranging in age from 12 to 28 years old. While undergoing an fMRI brain scan, the participants completed a task where they had to match emotional facial expressions (showing either fear or anger) or match the orientation of elliptical shapes as a control condition.

The researchers then compared the brain activity patterns between the ADHD and non-ADHD groups to look for differences in how their brains processed the emotional faces versus the neutral shapes. They were particularly interested in examining activity in the amygdala, a region of the brain involved in processing emotions, as well as how the amygdala interacted with other brain regions during the task.

Key Findings on Behavior and Brain Activity

Behavioral Results

Participants with ADHD were slower and less accurate at matching the emotional faces compared to the control group. However, they performed similarly to controls on the shape-matching control task. This suggests the ADHD group had more difficulty specifically with processing the emotional information rather than general problems with the task.

Brain Activation Differences

When viewing emotional faces compared to shapes, participants with ADHD showed less activation in several brain regions involved in visual processing and emotion, including:

• Left amygdala
• Hippocampus
• Fusiform gyrus
• Occipital cortex
• Posterior temporal cortex

The reduced activation in the left amygdala is particularly notable, as the amygdala plays a key role in processing emotional information. This lower amygdala response in the ADHD group may reflect differences in how their brains detect and process emotional cues from faces.

Brain Connectivity Differences

In addition to looking at activation of individual brain regions, the researchers examined how different regions communicated with each other during the task. They found an important difference in the functional connection between the right amygdala and an area called the ventromedial prefrontal cortex.

In participants without ADHD, there was increased positive coupling (i.e. synchronized activity) between the right amygdala and ventromedial prefrontal cortex specifically when viewing emotional faces compared to shapes. However, in the ADHD group, the coupling between these regions did not differ significantly between emotional and non-emotional stimuli.

This suggests the interaction between the amygdala and prefrontal regions during emotion processing works differently in individuals with ADHD. The connection between these areas is thought to be important for recognizing emotions and regulating emotional responses.

Implications of the Findings

The behavioral results showing slower and less accurate emotion matching in the ADHD group align with previous research indicating difficulties with emotion recognition in ADHD. The brain imaging findings provide new insight into the neural processes that may underlie these challenges.

The reduced amygdala activation when viewing emotional faces suggests the brains of people with ADHD may be less responsive to emotional cues. This could make it harder to detect and interpret emotions from facial expressions.

Additionally, the lack of increased coupling between the amygdala and ventromedial prefrontal cortex during emotion processing in the ADHD group may reflect problems with how emotional information is relayed to higher-level processing regions. The connection between these areas is thought to be important for categorizing emotions and generating appropriate responses.

Together, these differences in brain activation and connectivity could help explain why some individuals with ADHD struggle to quickly and accurately recognize emotions in others. This in turn may contribute to difficulties with social interactions and emotional self-regulation.

Limitations and Future Directions

It’s important to note that this study only examined brain responses during a simple emotion matching task. Future research using more complex and realistic emotion recognition scenarios could provide additional insights. The study also focused only on fearful and angry expressions, so it’s unclear if similar patterns would be seen for other emotions like happiness or sadness.

Additionally, the researchers did not find a direct relationship between participants’ brain activity patterns and their scores on a questionnaire measure of emotion regulation problems. This suggests the observed brain differences may not fully account for real-world emotional difficulties in ADHD. Other factors likely also play a role.

More research is needed to understand how these brain differences in emotion processing relate to social and emotional challenges in daily life for people with ADHD. Future studies could also examine whether treatments for ADHD affect these patterns of brain activation and connectivity.

Conclusions

• Adolescents and adults with ADHD showed reduced brain activation in regions involved in processing emotions, particularly the amygdala, when viewing emotional faces.
• The functional connection between the amygdala and prefrontal cortex worked differently in those with ADHD during emotion processing.
• These brain differences may contribute to difficulties recognizing emotions in others, which could impact social functioning in ADHD.
• Understanding the brain basis of emotion recognition challenges in ADHD may help inform the development of new interventions targeting these skills.

While more research is still needed, this study provides new insight into how the brains of people with ADHD process emotional information differently. The findings highlight the importance of considering emotional and social aspects of ADHD in addition to the core symptoms of inattention and hyperactivity/impulsivity. Improving our understanding of the neurobiology underlying emotion recognition difficulties may ultimately lead to better ways to support individuals with ADHD in navigating social and emotional challenges.