Is ADHD a Mental Illness?

Attention Deficit Hyperactivity Disorder (ADHD) is one of the most common mental health conditions in children and teens, affecting 18% of the worldwide population under age 18, and the number is steadily rising.  But what exactly is ADHD? And is it a mental illness?

What is Mental Illness?

According to the American Psychiatric Association, mental illnesses are health conditions involving changes in emotion, thinking or behavior, or a combination of these. Mental illnesses can be associated with distress and/or problems functioning in social, work or family activities. It is estimated that more than 1 in 5 adults in the U.S. has a diagnosable mental disorder.

What is ADHD?

ADHD is classified as a mental disorder and is diagnosed using criteria from the Diagnostic and Statistical Manual of Mental Disorders (DSM-5). These criteria include symptoms of inattention, hyperactivity and impulsivity. But as research in and knowledge of neuroscience increases, and we learn more about differences in brain structure and functioning, many question this blanket definition and look for alternative views of understanding one another.

ADHD is a neurodevelopmental condition, which means it is not strictly a mental health condition. And having ADHD doesn't inherently mean poor mental health. Traits like creativity, unique thinking, and high energy are hallmarks of ADHD, alongside the some more challenging symptoms. And because ADHD is one of the most researched of psychiatric disorders, neuroimaging and neuropsychological studies have pointed clearly to brain differences, providing strong evidence of it simultaneously being a biological disorder.

The latest research illustrates that ADHD is a genetic, neurological, nutritional and environmental condition, in which an imbalanced brain triggers imbalanced behaviors. It affects executive functioning and self-regulation across attention, behavior and emotion. As a result, people with ADHD struggle more than most in two areas:

(1) Persisting toward goals while resisting distractions

(2) Inhibiting impulsive actions.

How ADHD Affects the Brain

You may have heard the words neurodiverse or neurodivergent. According to Robert Jason Grant, founder of the AutPlay ™ Therapy Program and author of several books on Autism, neurodiversity is “the diversity that exists in neurotype among humans. Neurodivergent is a term that refers to individuals that diverge from societal constructed concepts of what is ‘typical’ or ‘normal’ in terms of navigating a society’s systems. Neurodivergent identity would include (but is not limited to) Autistic, ADHD, sensory differences, learning differences, intellectual development disorder, etc.”

Let’s take a quick look at what this means and how ADHD affects the brain.

ADHD impacts the executive functioning area of the brain, which is located in the prefrontal cortex and is the last area of the brain to develop. For neurotypical brains, adult maturation of the prefrontal cortex occurs between the ages of 25 and 30. Executive functioning skills include attention, focus, organization, planning, mental flexibility, emotion regulation, and impulse control.

In other words, the prefrontal cortex is the intersection for attention, behavior and emotional response. People with ADHD may have a thinner prefrontal cortex and/or one with a different structure than a neurotypical brain. This means that those with ADHD may have shortfalls in one or more of these areas: decision-making, planning, time management, procrastination, social skills development, maintaining relationships, and externalization of behaviors such as disruptive, aggressive, and defiant behaviors, or lack of impulse control.

The hippocampus, on the other hand, which is associated with long-term memory and working memory, is larger in individuals with ADHD. Working memory is the ability to hold on to information in your memory while performing other tasks, a skill often used when following instructions, concentrating, or memory that's needed in the present moment—for example, listing to directions while remembering an address, remembering the steps of a math problem while doing a math problem—all skills that lag in people with ADHD. Researchers have concluded that this size difference may be the brain's attempt to compensate for disruptions in time perception, tendency to avoid waiting, and sensation-seeking behaviors associated with ADHD.  

But let’s not forget the positive qualities of ADHD and there are many. The ADD & ADHD Answer Book, by Susan Ashley, Ph.D. recommends a few reframes and how we can view these as ADHD “Gifts:”

Impulsive                      Lives Fully in the Moment

Hyperactive                 Energetic

Obsessed                    Passionate

Loses Things                 Unattached to Material Objects

Selfish                          Knows How to Get Needs Met

Daydreamer                Get Access States of Relaxation

Tunes Out Others        Strong Sense of Purpose

All of this amounts to what we call a neurodiverse brain, the opposite of neurotypical. So although the DSM-5 is the gold standard for diagnosing mental health conditions, neuroscience research is forcing us to take another look at how we define and diagnose mental illness and conditions such as ADHD.