Examples of Mental Illness

Examples of mental illness, when added to a definition of mental illness, help deepen our understanding of what mental disorders really are. Mental illness examples can be found among the approximately 300 mental disorders listed and explained in the nearly 1000-page Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5). The DSM-5 is the official and universally accepted (although sometimes criticized) guide to mental illness published by the American Psychiatric Association (2013). Some disorders are extremely rare, and other mental disorders are relatively common.

Before we get into examples of mental health disorders, it's important to note that some mental illnesses are recognized more than others because they affect so many people, both people who live with them and those who are connected to those individuals. For example, while many people have at least heard of obsessive-compulsive disorder (OCD)—thanks in part to the term being not only overused but misused—not everyone has heard of excoriation, a skin-picking disorder in the same diagnostic category as OCD. Here are some examples of mental illness that occur somewhat frequently. 

Common Examples of Mental Illness

The following psychiatric disorders are among the most prevalent mental illnesses negatively impacting people and interfering in their lives:

Knowing examples of mental illness helps us understand what mental illness is, what it does. Here are common examples of mental illness?

Examples of Mental Illness in Clusters

Mental health experts from various fields sometimes use clusters to help people better understand what mental illness is and how it affects human beings. Not everyone uses the exact same clusters, but that's okay. The clusters aren't official, but they are helpful. When placed into clusters, examples of mental illness have more meaning.

McNally (2011) discusses psychiatrist Paul McHugh's division of mental health conditions into four clusters. These clusters describe the characteristics of the disorders that belong to each.

  • What someone has
  • Problems in the brain impacting perception, thoughts, and/or emotions
  • Examples include schizophrenia, bipolar disorders, and Alzheimer's disease
  • What someone is like
  • When someone falls onto the extreme points of the continua of each of the Big Five personality traits (extraversion, agreeableness, conscientiousness, neuroticism, and openness)
  • Challenges here aren't always a mental illness; extreme shyness, for example, doesn't always produce the severity of distress that social anxiety disorder does
  • A very important note: mental illness is never who somebody is, nor can someone described as a mental illness. This category looks at official personality traits to see how extremes measures of the traits relate to defined mental illnesses.
  • Personality disorder types, incidentally, aren't included in this cluster because they're not considered to be mental illness (at least not in the U.S.) Personality disorders, rather than being illnesses, are rigid, inflexible behavior patterns and responses to social situations.
  • What someone is doing
  • What someone has encountered
  • Problems that are more like injuries that diseases
  • PTSD is the most common example of mental illness in this cluster

Examples of Mental Illness Are Important

Knowing examples of mental illness is another step in understanding exactly what mental illness is and how it impacts people's lives. When people increase awareness of what, exactly, mental illness is, society will be less quick to use the terms incorrectly (ever heard someone say that "the weather is so bipolar"?). This means that we'll be more likely to understand each other as human beings.

APA Reference
Peterson, T. (2019, October 1). Examples of Mental Illness, HealthyPlace. Retrieved on 2024, May 28 from

Last Updated: October 23, 2019

Medically reviewed by Harry Croft, MD

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