Types of Mental Illness
There are many different conditions that are recognized as mental illnesses. The
more common types include:
Anxiety disorders: People with anxiety disorders respond to certain objects or
situations with fear and dread, as well as with physical signs of anxiety or panic, such
as a rapid heartbeat and sweating. An anxiety disorder is diagnosed if the person’s
response is not appropriate for the situation, if the person cannot control the
response, or if the anxiety interferes with normal functioning. Anxiety disorders
include generalized anxiety disorder, panic disorder, social anxiety disorder, and
Mood disorders: These disorders, also called affective disorders, involve persistent
feelings of sadness or periods of feeling overly happy, or fluctuations from extreme
happiness to extreme sadness. The most common mood disorders
are depression, bipolar disorder, and cyclothymic disorder.
Psychotic disorders: Psychotic disorders involve distorted awareness and thinking.
Two of the most common symptoms of psychotic disorders are hallucinations — the
experience of images or sounds that are not real, such as hearing voices — and
delusions, which are false fixed beliefs that the ill person accepts as true, despite
evidence to the contrary. Schizophrenia is an example of a psychotic disorder.
Eating disorders: Eating disorders involve extreme emotions, attitudes, and
behaviors involving weight and food. Anorexia nervosa, bulimia nervosa, and binge
eating disorder are the most common eating disorders.
Impulse control and addiction disorders: People with impulse control disorders are
unable to resist urges, or impulses, to perform acts that could be harmful to
themselves or others. Pyromania (starting fires), kleptomania (stealing), and
compulsive gambling are examples of impulse control disorders. Alcohol and drug
are common objects of addictions. Often, people with these disorders become so
involved with the objects of their addiction that they begin to ignore responsibilities
Personality disorders: People with personality disorders have extreme and
inflexible personality traits that are distressing to the person and/or cause problems
in work, school, or socialrelationships. In addition, the person’s patterns of thinking
and behavior significantly differ from the expectations of society and are so rigid
that they interfere with the person’s normal functioning. Examples include antisocial
personality disorder, obsessive-compulsive personality disorder, and paranoid
Obsessive-compulsive disorder (OCD): People with OCD are plagued by constant
thoughts or fears that cause them to perform certain rituals or routines. The
disturbing thoughts are called obsessions, and the rituals are called compulsions. An
example is a person with an unreasonable fear of germs who constantly washes his
or her hands.
Post-traumatic stress disorder (PTSD): PTSD is a condition that can develop
following a traumatic and/or terrifying event, such as a sexual or physical assault,
the unexpected death of a loved one, or a natural disaster. People with PTSD often
have lasting and frightening thoughts and memories of the event, and tend to be
Stress response syndromes (formerly called adjustment disorders):Stress response
syndromes occur when a person develops emotional or behavioral symptoms in
response to a stressful event or situation. The stressors may include natural
disasters, such as an earthquake or tornado; events or crises, such as a car accident
or the diagnosis of a major illness; or interpersonal problems, such as a divorce,
death of a loved one, loss of a job, or a problem withsubstance abuse. Stress response
syndromes usually begin within three months of the event or situation and ends
within six months after the stressor stops or is eliminated.
Dissociative disorders: People with these disorders suffer severe disturbances or
changes in memory, consciousness, identity, and general awareness of themselves
and their surroundings. These disorders usually are associated with overwhelming
stress, which may be the result of traumatic events, accidents, or disasters that may
be experienced or witnessed by the individual. Dissociative identity disorder,
formerly called multiple personality disorder, or “split personality,” and
depersonalization disorder are examples of dissociative disorders.
Factitious disorders: Factitious disorders are conditions in which a person
knowingly and intentionally creates or complains of physical and/or emotional
symptoms in order to place the individual in the role of a patient or a person in need
Sexual and gender disorders: These include disorders that affect sexual desire,
performance, and behavior. Sexual dysfunction, gender identity disorder, and the
paraphilias are examples of sexual and gender disorders.
Somatic symptom disorders: A person with a somatic symptom disorder, formerly
known as a psychosomatic disorder orsomatoform disorder, experiences physical
symptoms of an illness or of pain, even though a doctor can find no medical cause for
Tic disorders: People with tic disorders make sounds or display body movements
that are repeated, quick, sudden, and/or uncontrollable. (Sounds that are made
involuntarily are called vocal tics.) Tourette’s syndrome is an example of a tic
Other diseases or conditions, including various sleep-related problems and many
forms of dementia, including Alzheimer’s disease, are sometimes classified as mental
illnesses, because they involve thebrain.