Is ADHD a Mental Illness?

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ADHD is a diagnosable mental disorder that is characterized by problems with focus, hyperactivity, and impulsiveness. It is estimated to affect 4% of adults and 9% of children in the United States. At the same time, whether ADHD can be considered a mental illness is less clear.

Kara Nassour, LPC, NCC, a licensed professional counselor practicing at Shaded Bough Counseling in Austin, Texas addresses this complication:

"ADHD is a mental disorder listed alongside other mental disorders by the American Psychiatric Association. But the idea of it as an 'illness' has become more complicated in recent years," Nassour says. "The neurodiversity movement argues that many things considered 'disorders' are actually healthy differences in brain development. These differences may appear 'disordered' because our culture doesn't take ADHD people's needs into account, so they face extra difficulties at school and work."

It's clear that ADHD can present challenges in life, but the question of whether it is a mental illness may still be up for debate.

What Is a Mental Illness?  

A mental illness is defined as a health condition that changes a person’s thinking, feelings, or behavior (or all three) and that causes the person distress and difficulty functioning. A mental illness can be caused by a reaction to a traumatic event, a genetic predisposition, or a chemical imbalance. Mental illnesses are often treated with therapy, medication, or both.

Each mental illness has a defined set of diagnostic criteria laid out by the American Psychiatric Association in the Diagnostic and Statistical Manual of Mental Disorders (DSM). The DSM is the standard reference used by mental health professionals to diagnose mental disorders.

To be diagnosed with a mental illness, a person must meet the criteria laid out in the DSM for that specific disorder. The DSM criteria for each mental illness are based on extensive research and are constantly being updated as new information becomes available.

However, the term "mental illness" is sometimes considered to be a stigmatizing label. In recent years, there has been a push to use the more neutral term "mental health condition" instead.

Types of Mental Illnesses

Below are some of the most common mental illnesses.

Anxiety Disorders

These disorders involve persistent and excessive fear or worry. Examples include the following:

Mood Disorders

These disorders involve persistently depressed mood or loss of interest in activities. Examples include the following:

Eating Disorders

These disorders involve distorted eating habits and severe distress or concern about body weight or shape. Examples include the following:

Trauma-Related Disorders

These disorders are caused by exposure to a traumatic event. Examples include the following:

Psychotic Disorders

These disorders involve a break from reality. Examples include the following:

Personality Disorders

These disorders involve rigid and unhealthy patterns of thinking, feeling, and behaving. Examples include the following:

Developmental Disorders

These disorders begin in childhood and can affect a person's ability to function socially, academically, and vocationally. Examples include the following:

What’s the Difference Between a Mental Illness and a Mental Disorder? 

The terms "mental illness" and "mental disorder" are often used interchangeably, but there is a distinction between the two.

  • Mental illness is a general term that refers to all mental health conditions.
  • Mental disorder is a more specific term that refers to mental illnesses that are diagnosable according to a set of criteria.

In terms of whether these terms can be used interchangeably, the answer is yes and no. In general, the terms can be used interchangeably because they both refer to mental health conditions that affect a person’s thinking, feelings, or behavior.

However, there are some instances where it is important to use the term "mental illness" instead of "mental disorder." For example, when discussing mental health in a general sense or when referring to someone who does not have a diagnosable mental disorder.

Other terms used to describe mental health concerns, in general, include the following:

  • Mental health issues
  • Mental health problems
  • Mental health challenges

Other terms used to describe mental health disorders include the following:

With respect to the difference between the terms "mental health condition" and "mental disability," the following can be noted:

  • "Mental health condition" refers to any type of mental illness.
  • "Mental disability" is used to describe a mental illness that significantly interferes with one or more major life activities.

It’s important to note that not all mental health conditions are considered mental illnesses. For example, grief is a normal reaction to loss and does not necessarily constitute a mental illness. Similarly, stress can be a normal part of life and is not always indicative of a mental health condition.

In terms of stigma, the term "mental illness" is often seen as more stigmatizing than the term "mental disorder." This is likely because the word "illness" implies that there is something wrong with a person. In contrast, the term "disorder" suggests that a person has an imbalance or abnormality.

How Is ADHD Classified?

ADHD is classified according to the DSM as a mental disorder. Specifically, it is classified as a neurodevelopmental disorder in the fifth edition, text revisions of the DSM (DSM-5-TR). Other classification systems, such as the International Classification of Diseases (ICD), also consider ADHD to be a mental disorder.

In contrast, some individuals with ADHD choose not to see it as a mental disorder. This is often because they feel that the term "disorder" is stigmatizing. Instead, they prefer to think of ADHD as a difference or neurodiversity.

History of the Classification of ADHD

In terms of how the classification of ADHD has changed throughout history, it is worth noting that the condition was not always considered a mental disorder. In fact, it was not until the early 1900s that ADHD began to be seen as a medical condition.

The first time ADHD was mentioned in the DSM was in the third edition (DSM-III), which was published in 1980. At this time, ADHD was classified as a disorder of childhood onset. In the DSM-III-R, which was published in 1987, ADHD was reclassified as a disorder that could occur in both children and adults.

In the DSM-IV, which was published in 1994, ADHD was classified as a disorder that could occur in three different subtypes: predominantly inattentive, predominantly hyperactive-impulsive, and combined. The DSM-5, which was published in 2013, made some changes to the age of onset criteria.

Classification and Controversy

In more general terms, the classification of ADHD as a mental illness has been controversial. Some people argue that ADHD is not a mental illness because it does not fit the traditional definition of a mental disorder. Others argue that ADHD should be classified as a mental disorder because it can significantly impair a person’s ability to function in daily life.

Scott Allen, PsyD, Director of Neurodiversity Services at Just Mind Counseling in Texas, notes the following:

"Although ADHD is classified as a 'mental disorder,' it represents a different way of thinking and processing the world. With the right opportunities, settings and support, people with ADHD can and do live and work successfully," Allen says.

Many of our innovators/groundbreakers have neurological profiles consistent with ADHD, which makes sense because they often have to 'improvise' or use 'lifehacks' in order to adhere to current societal demands.


The debate over whether or not ADHD is a mental illness is likely to continue. However, it is important to remember that how a condition is classified does not necessarily change the way it is treated. Whether or not ADHD is considered a mental illness, there are effective treatments available that can help people manage the symptoms and live productive and fulfilling lives.

6 Sources
Verywell Mind uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. National Institute of Mental Health. Attention-Deficit/Hyperactivity Disorder (ADHD).

  2. American Psychiatric Association. What Is Mental Illness?

  3. World Health Organization. Mental Disorders.

  4. Linden M. Definition and Assessment of Disability in Mental Disorders under the Perspective of the International Classification of Functioning Disability and Health (ICF)Behav Sci Law. 2017;35(2):124-134. doi:10.1002/bsl.2283

  5. Doernberg E, Hollander E. Neurodevelopmental Disorders (ASD and ADHD): DSM-5, ICD-10, and ICD-11CNS Spectr. 2016;21(4):295-299. doi:10.1017/S1092852916000262

  6. Lange KW, Reichl S, Lange KM, Tucha L, Tucha O. The history of attention deficit hyperactivity disorder. Atten Defic Hyperact Disord. 2010 Dec;2(4):241-55. doi: 10.1007/s12402-010-0045-8. Epub 2010 Nov 30. PMID: 21258430; PMCID: PMC3000907.

By Arlin Cuncic, MA
Arlin Cuncic, MA, is the author of "Therapy in Focus: What to Expect from CBT for Social Anxiety Disorder" and "7 Weeks to Reduce Anxiety." She has a Master's degree in psychology.