Psychological Disorders: Types, Diagnosis, and Facts

Author: Disabled World (DW)
Updated/Revised Date: 30 Jul 2026

Table of Contents:
Synopsis - Definition - About This Section - FAQs - Publications - Subtopics

Synopsis

An overview of psychological disorders, including how they are defined, classified, and diagnosed, plus types, the DSM, counseling, and key statistics.

At a Glance

• 1 - For a mental state to be classed as a disorder, it generally needs to cause dysfunction.
• 2 - The DSM-IV is published by the American Psychiatric Association and is sometimes called the Psychiatrists Bible.
• 3 - The DSM-IV organizes psychological disorders across five Axes, ranging from clinical syndromes to a person's highest level of functioning.
• 4 - Roughly 26.2 percent of American adults, about one in four, have a diagnosable mental disorder in a given year, equal to about 57.7 million people.

Topic Definition

Psychological Disorders

Psychological disorders, also known as mental illnesses or psychiatric disorders, are patterns of thinking, feeling, or behavior that cause a person distress or impair their ability to function in everyday life, and that fall outside what is considered a developmental or social norm. For a mental state to be classified as a disorder, it generally needs to cause meaningful dysfunction rather than simply reflect ordinary variation in mood or personality. These conditions cover a wide spectrum, from anxiety disorders and phobias to mood disorders, personality disorders, psychotic disorders, and substance-related disorders, and their effects can range from mild and short-lived to severe and lasting. Health care providers often draw on the Diagnostic and Statistical Manual of Mental Disorders to help identify and classify these conditions, though diagnosis ultimately relies on professional judgment, research, and experience. Because a person's mental and physical health are deeply connected, addressing a psychological disorder through counseling, treatment, and support benefits overall well-being, and such conditions can affect anyone regardless of age, wealth, or outward appearance.

Overview

The World Health Organization (WHO) estimates 1 in 8 people (almost 1 billion in total) live with some form of psychiatric condition.

A mental disorder, also called a mental illness or psychiatric disorder, is a mental or behavioral pattern or anomaly that causes either suffering or an impaired ability to function in ordinary life (disability), and which is not a developmental or social norm. The definition and classification of mental disorders are key issues for researchers as well as service providers and those who may be diagnosed. For a mental state to classify as a disorder, it generally needs to cause dysfunction.

There are many psychological disorders that people may experience in life, ranging from Post-Traumatic Stress Disorder to common phobias. Diagnosis and treatment of psychological disorders is an objective procedure that involves prior research as well as experience for the health care provider.

Some disorders may be very limited in their functional effects, while others may involve substantial disability and support needs. The degree of ability or disability may vary over time and across different life domains. Furthermore, continued disability has been linked to institutionalization, discrimination and social exclusion as well as to the inherent effects of disorders. Alternatively, functioning may be affected by the stress of having to hide a condition in work or school etc., by adverse effects of medications or other substances, or by mismatches between illness-related variations and demands for regularity. Knowledge of psychological disorders has been compiled into a large and comprehensive manual called the 'DSM-IV,' which is used by health care providers today.

The Diagnostic and Statistical Manual of Mental Disorders (DSM-IV)

The Diagnostic and Statistical Manual of Mental Disorders (DSM-IV) is published by the American Psychiatric Association. The book contains all the known mental health and psychological disorders impacting both adults and children.

The DSM-IV lists the names and symptoms of psychological disorders, as well as potential causes, treatments, statistics, and research that is being pursued related to these disorders. The DSM-IV is sometimes referred to as the 'Psychiatrists Bible,' because it enhances the understanding of persons with these disorders, their treatment options, and even third-party insurance payers.

Psychological disorders in the DSM-IV are both classified and explained. Within the DSM-IV there are five, 'Axes,' that cover psychological disorders:

• Axis 1: Presents Clinical Syndromes, also known as the diagnosis of the psychological disorder.
• Axis 2: Presents Developmental Disorders and Personality Disorders. Developmental disorders typically occur in childhood, and can affect physical, intellectual, and emotional development (e.g., autism, Down's syndrome). Personality disorders have long-lasting symptoms that alter one's interaction in the world.
• Axis 3: Presents Physical Conditions, such as brain injuries or physical impairments. Some psychological disorders spring from physical aspects, others have unknown causes.
• Axis 4: Presents Severity of Psychosocial Stressors, including events in the patient's life; deaths, divorces, traumas, celebrations, new beginnings, etc. Lifestyle influences most psychological disorders.
• Axis 5: Presents The Highest Level of Functioning - describes how well the person functions at present and within the last year, with the psychological disorder.

The DSM-IV is not necessarily used or involved in the diagnostic process or treatment of every psychological disorder. Reference to and use of the DSM-IV depends on the Psychologist, Psychiatrist, or Counselor. Whether the DSM-IV was used in the diagnostic process, it is important to get objective support regarding any psychological condition or disorder.

Counseling and Psychological Disorders

There has been an amount of social stigma associated with counseling and psychological disorders, or psychological disorders in general, causing unnecessary burden and people with disabilities, their family members and friends.

The counseling process can be trying enough without dealing with any stigmas associated with it. Insurance companies may not cover counseling easily as well. Overcoming these hurdles related to seeing a psychologist, psychiatrist, or a counselor can be extremely valuable to a person as a whole; not just their emotions and mind.

A person's physical health is intrinsically connected to their mind and soul; dealing with your mental well-being inevitably benefits your overall health. As with any physical disease, a psychological disorder can affect any person at any time in their life; it does not matter how happy, wealthy, or seemingly well-adjusted they may be.

Types of Psychological Disorders:

Anxiety Disorders

Childhood Disorders

Eating Disorders

Mood Disorders

Cognitive Disorders (Delirium, Dementia, Amnestic Disorders)

Personality Disorders

Schizophrenia and Other Psychotic Disorders

Substance-Related Disorders

Facts and Statistics

• An estimated 26.2 percent of Americans ages 18 and older, or about one in four adults, suffer from a diagnosable mental disorder in a given year. When applied to the 2004 U.S. Census residential population estimate for ages 18 and older, this figure translates to 57.7 million people.
• Many people suffer from more than one mental disorder at a given time. In particular, depressive illnesses tend to co-occur with substance abuse and anxiety disorders.
• Approximately about 18% of people, ages 18- 54 in a given year, have an anxiety disorder in a given year. Anxiety disorders include: panic disorder, obsessive-compulsive disorder (OCD), post-traumatic stress disorder (PTSD), generalized anxiety disorder (GAD), and phobias (social phobia, agoraphobia, and specific phobia).
• Most people who commit suicide have a diagnosable mental disorder, most commonly a depressive disorder or a substance abuse disorder.

Frequently Asked Questions

What is the difference between the DSM-IV and the DSM-5?

The DSM-5 is a later edition that replaced the multi-axis system of the DSM-IV with a single-axis approach and updated several diagnostic categories. Both are published by the American Psychiatric Association.

What is the difference between a psychologist and a psychiatrist?

A psychiatrist is a medical doctor who can prescribe medication, while a psychologist typically focuses on assessment and talk therapy. Many people work with both as part of a treatment plan.

Can psychological disorders be cured?

Many disorders are highly manageable rather than fully cured. With therapy, medication, and support, people often reduce symptoms significantly and lead full, productive lives.

When should someone seek help for a mental health concern?

It is wise to seek help when symptoms interfere with work, relationships, or daily functioning, or cause ongoing distress. Early support often leads to better outcomes.

Are psychological disorders hereditary?

Genetics can raise the risk for some disorders, but environment, life stress, and other factors also play a role. Having a family history does not guarantee a person will develop a condition.

How are psychological disorders treated?

Common treatments include psychotherapy, medication, lifestyle changes, and support groups. The right combination depends on the specific disorder, its severity, and the individual's needs.

Does health insurance cover mental health treatment?

Coverage varies by plan and region. Many policies include mental health benefits, but it is best to confirm details such as copays, provider networks, and session limits directly with the insurer.

Curated and edited by Ian C. Langtree, Founder & Editor-in-Chief, Disabled World. This section is maintained by the Disabled World editorial team.

Last updated: 30 Jul 2026