About five percent of people are affected with ADHD, according to a study published in The Lancet Psychiatry in 2018. Beyond that five percent, even more do not meet the full criteria, but still have difficulties with focusing and impulse control. Many kids with ADHD tend to struggle more in school. According to the study, if left undiagnosed, ADHD can lead to an unsuccessful adult life both socially and financially. However, some of the specific causes of ADHD are still a mystery — particularly in girls — which contributed to the prevalence of people who are undiagnosed or misdiagnosed.
It was originally thought that ADHD was just a human condition, but a recent study published in Translational Psychiatry in 2021 found that “canine hyperactivity, impulsivity, and inattention share similar demographic risk factors and behavioral comorbidities with human ADHD.” This suggests that this condition appears in dogs as well. Observing how ADHD affects dogs has useful applications for studying humans. Results showed that high levels of hyperactivity inattention were more common in young male dogs. This is notable considering that ADHD is also often noticed in young, male humans, suggesting that dogs might be a good model for studying ADHD. There was also a correlation shown with being aggressive or shy, something that is also documented in humans with ADHD. Given that dogs have many similar traits to humans, this doesn’t come as much of a surprise. The study also found that many of the neurological pathways that play a role in ADHD in humans are similarly affected in dogs, further solidifying that dogs may be a good model for ADHD research. ADHD and impulsive behavior can come from disruptions in the frontostriatal circuit and activation of the prefrontal cortex (PFC). The anterior cingulate cortex (ACC) and striatum are also involved in human ADHD as well as in dogs. Neurological pathways involved in aggressiveness also connect to PFC and striatum, and fear and anxiety are also associated with activity in PFC and ACC in both humans and dogs.
“…many of the neurological pathways that play a role in ADHD in humans are similarly affected in dogs, further solidifying that dogs may be a good model for ADHD research.”
The study also found that dogs who spend more time alone and lack exercise and socialization are more prone to developing ADHD. Some can get stressed when they are alone, which leads to increased levels of fear and anxiety. The pathways in the brain relating to the PFC can be overactivated and contribute to impulsive behaviors and ADHD traits. While all dogs can exhibit ADHD symptoms, some breeds may be more vulnerable than others. For working breeds such as the border collie and German shepherd, ADHD characteristics were more common. In contrast, dogs kept usually as pets like poodles and chihuahuas were calmer but also displayed inattention. Dogs kept as pets were shown to not display ADHD traits at all or in the same capacity that work-bred dogs did. The study notes that this could be because these dogs don’t have to concentrate in the same capacity that dogs bred for work have to.
“…dogs who spend more time alone and lack exercise and socialization are more prone to developing ADHD.”
Research in humans shows an ADHD brain differs from a neurotypical one, but how do increased levels of hyperactivity and inattention affect dogs’ brains? Do parts of a dog’s brain also mature at slower rates, similar to humans with ADHD? Future research should investigate these kinds of questions. According to the article “The ADHD vs. Non-ADHD Brain” published in Very Well Mind, the amygdala and hippocampus — responsible for emotional processing — are smaller in the brains of those with ADHD. Dopamine regulation is also different. Evidence also showed that ADHD may be related to dysfunctional brain connectivity. Research using resting-state MRIs suggests that individuals with ADHD may have “increased functional connectivity in certain regions of the brain” which is interesting when comparing it to a neurotypical brain, and raises questions for how and why ADHD increases the functionality of only some parts of the brain. One might wonder if these neurological differences are similar in dogs, and if they are, what could work in dogs to regulate traits of ADHD that could work in humans.
Translational Psychiatry (2021). DOI: 10.1038/s41398-021-01626-x
The Lancet Psychiatry (2018). DOI: 10.1016/ S2215-0366(17)30167-0
