Learning about common mental illnesses

The Substance Abuse and Mental Health Services Administration (SAMHSA) defines mental health problems as health conditions that involve changes in thinking, mood, and/or behavior and are associated with distress or impaired functioning. When these problems become more severe, they become mental illnesses.

These include anxiety disorders, eating disorders, schizophrenia, and others. When these occur in a child under 18, they are referred to as serious emotional disturbances (SEDS). SAMHSA’s descriptions of these disorders can be read below, or by selecting the appropriate category link to the left.

Much more information can be found at the National Institute of Mental Health website.

Is drug addiction a mental illness? Yes, according to the National Institute on Drug Abuse (NIDA). That’s because addiction changes the brain in fundamental ways, disturbing a person's normal hierarchy of needs and desires and substituting new priorities connected with procuring and using the drug. The resulting compulsive behaviors that override the ability to control impulses despite the consequences are similar to hallmarks of other mental illnesses.

In fact, the Diagnostic and Statistical Manual of Mental Disorders (DSM), which is the definitive resource of diagnostic criteria for all mental disorders, includes criteria for drug use disorders, distinguishing between two types: drug abuse and drug dependence. Drug dependence is synonymous with addiction. By comparison, the criteria for drug abuse hinge on the harmful consequences of repeated use but do not include the compulsive use, tolerance (i.e., needing higher doses to achieve the same effect), or withdrawal (i.e., symptoms that occur when use is stopped) that can be signs of addiction.

What is Comorbity?

When two disorders or illnesses occur in the same person, simultaneously or sequentially, they are described as comorbid. Comorbidity also implies interactions between the illnesses that affect the course and prognosis of both.

How common are comorbid drug use and other mental disorders?

Many people who regularly abuse drugs are also diagnosed with mental disorders and vice versa. The high prevalence of this comorbidity has been documented in multiple national population surveys since the 1980s. Data show that persons diagnosed with mood or anxiety disorders are about twice as likely to suffer also from a drug use disorder (abuse or dependence) compared with respondents in general. The same is true for those diagnosed with an antisocial syndrome, such as antisocial personality or conduct disorder. Similarly, persons diagnosed with drug disorders are roughly twice as likely to suffer also from mood and anxiety disorders

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ADHD affects as many as 2 million American children and is a diagnosis applied to children and adults who consistently display certain characteristic behaviors over a period of time. The most common behaviors fall into three categories: inattention, hyperactivity, and impulsivity. People who are inattentive have a hard time keeping their mind on any one thing and may get bored with a task after only a few minutes.

People who are hyperactive always seem to be in motion. They can't sit still and may dash around or talk incessantly. People who are overly impulsive seem unable to curb their immediate reactions or think before they act. Not everyone who is overly hyperactive, inattentive, or impulsive has an attention disorder. While the cause of ADHD is unknown, in the last decade, scientists have learned much about the course of the disorder and are now able to identify and treat children, adolescents, and adults who have it. A variety of medications, behavior-changing therapies, and educational options are already available to help people with ADHD focus their attention, build self-esteem, and function in new ways.

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Panic Disorder

Panic disorder affects about 2.4 million adult Americans and is twice as common in women as in men. A panic attack is a feeling of sudden terror that often occurs with a pounding heart, sweating, nausea, chest pain or smothering sensations and feelings of faintness or dizziness. Panic disorder frequently occurs in addition to other serious conditions like depression, drug abuse, or alcoholism. If left untreated, it may lead to a pattern of avoidance of places or situations where panic attacks have occurred. In about a third of cases, the threat of a panic attack becomes so overwhelming that a person may become isolated or housebound—a condition known as agoraphobia. Panic disorder is one of the most treatable of the anxiety disorders through medications or psychotherapy. Early treatment of panic disorder can help prevent agoraphobia.

Obsessive-Compulsive Disorder (OCD)

OCD affects about 3.3 million adult Americans, and occurs equally in men and women. It usually appears in childhood. Persons with OCD suffer from persistent and unwelcome anxious thoughts, and the result is the need to perform rituals to maintain control. For instance, a person obsessed with germs or dirt may wash his hands constantly. Feelings of doubt can make another person check on things repeatedly. Others may touch or count things or see repeated images that disturb them. These thoughts are called obsessions, and the rituals that are performed to try to prevent or get rid of them are called compulsions. Severe OCD can consume so much of a person's time and concentration that it interferes with daily life. OCD responds to treatment with medications or psychotherapy.

Post-Traumatic Stress Disorder (PTSD)

PTSD affects about 5.2 million adult Americans, but women are more likely than men to develop it. PTSD occurs after an individual experiences a terrifying event such as an accident, an attack, military combat, or a natural disaster. With PTSD, individuals relive their trauma through nightmares or disturbing thoughts throughout the day that may make them feel detached, numb, irritable, or more aggressive. Ordinary events can begin to cause flashbacks or terrifying thoughts. Some people recover a few months after the event, but other people will suffer lasting or chronic PTSD. People with PTSD can be helped by medications and psychotherapy.

Generalized Anxiety Disorder (GAD)

GAD affects about 4 million adult Americans and twice as many women as men. GAD is more than day-to-day anxiety. It fills an individual with an overwhelming sense of worry and tension. A person with GAD might always expect disaster to occur or worry a lot about health, money, family, or work. These worries may bring physical symptoms, especially fatigue, headaches, muscle tension, muscle aches, trouble swallowing, trembling, twitching, irritability, sweating, and hot flashes. People with GAD may feel lightheaded, out of breath, or nauseous, or might have to go to the bathroom often. When people have mild GAD, they may be able to function normally in social settings or on the job. If GAD is severe, however, it can be very debilitating. GAD is commonly treated with medications.

Social Anxiety Disorder

Social phobia affects about 5.3 million adult Americans. Women and men are equally likely to develop social phobia, which is characterized by an intense feeling of anxiety and dread about social situations. These individuals suffer a persistent fear of being watched and judged by others and being humiliated or embarrassed by their own actions. Social phobia can be limited to only one type of situation-fear of speaking in formal or informal situations, eating, drinking, or writing in front of others-or a person may experience symptoms any time they are around people. It may even keep people from going to work or school on some days, as physical symptoms such as blushing, profuse sweating, trembling, nausea, and difficulty talking often accompany the intense anxiety. Social phobia can be treated successfully with medications or psychotherapy.

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Autism is a group of developmental brain disorders, collectively called autism spectrum disorder (ASD). The term “spectrum” refers to the wide range of symptoms, skills, and levels of impairment, or disability, that children with ASD can have. Some children are mildly impaired by their symptoms, but others are severely disabled.
ASD is diagnosed according to guidelines listed in the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition - Text Revision (DSM-IV-TR). The manual currently defines five disorders, sometimes called pervasive developmental disorders (PDDs), as ASD:

  • Autistic disorder (classic autism)
  • Asperger's disorder (Asperger syndrome)
  • Pervasive developmental disorder not otherwise specified (PDD-NOS)
  • Rett's disorder (RETT syndrome)
  • Childhood disintegrative disorder (CDD)

Information can also be found on the Eunice Kennedy Shriver National Institute of Child Health and Human Development website.

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About 18.8 million American adults experience a depressive illness that involves the body, mood, and thoughts. Depression affects the way a person eats and sleeps, the way one feels about oneself, and the way one thinks about things. People with a depressive illness cannot just "pull themselves together" and get better. Without treatment, symptoms can last for weeks, months, or years.

Major Depressive Disorder

Major depressive disorder involves a pervading sense of sadness and/or loss of interest or pleasure in most activities that interferes with the ability to work, study, sleep, eat, and enjoy once pleasurable activities. This is a severe condition that can impact a person's thoughts, sense of self worth, sleep, appetite, energy, and concentration. The condition can occur as a single debilitating episode or as recurring episodes.


Dysthymia involves a chronic disturbance of mood in which an individual often feels little satisfaction with activities of life most of the time. Many people with dysthymia also experience major depressive episodes in their lives leading to a recurrent depressive disorder. The average length of an episode of dysthymia is about four years.

Minor Depression

Minor depression is characterized by having symptoms for 2 weeks or longer that do not meet full criteria for major depression. Without treatment, people with minor depression are at high risk for developing major depressive disorder. Some forms of depression are slightly different, or they may develop under unique circumstances. However, not everyone agrees on how to characterize and define these forms of depression. They include:

  • Psychotic depression, which occurs when a person has severe depression plus some form of psychosis, such as having disturbing false beliefs or a break with reality (delusions), or hearing or seeing upsetting things that others cannot hear or see (hallucinations).
  • Postpartum depression, which is much more serious than the “baby blues” that many women experience after giving birth, when hormonal and physical changes and the new responsibility of caring for a newborn can be overwhelming. It is estimated that 10 to 15 percent of women experience postpartum depression after giving birth.
  • Seasonal affective disorder (SAD), which is characterized by the onset of depression during the winter months, when there is less natural sunlight. The depression generally lifts during spring and summer. SAD may be effectively treated with light therapy, but nearly half of those with SAD do not get better with light therapy alone. Antidepressant medication and psychotherapy can reduce SAD symptoms, either alone or in combination with light therapy.

Bipolar Disorder

Bipolar Disorder, or manic-depressive illness, is a type of mood disorder characterized by recurrent episodes of highs (mania) and lows (depression) in mood. These episodes involve extreme changes in mood, energy, and behavior. Manic symptoms include extreme irritable or elevated mood, a very inflated sense of self-importance, risk behaviors, distractibility, increased energy, and a decreased need for sleep.

The most important thing to do for people with depression is to help them get an appropriate diagnosis and treatment. Treatment, usually in the form of medication or psychotherapy, can help people who suffer from depression.

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Anorexia Nervosa

People with this disorder see themselves as overweight despite their actual body weight. With this disorder, a person works to maintain a weight lower than normal for their age and height. This is accompanied by an intense fear of weight gain or looking fat. At times, a person can even deny the seriousness of their low body weight. Eating becomes an obsession and habits develop, such as avoiding meals, picking out a few foods and eating these in small quantities, or carefully weighing and portioning food. People with anorexia may repeatedly check their body weight, and many engage in other techniques to control their weight, like compulsive exercise or purging by vomiting or using laxatives. Some people fully recover after a single episode; some have a pattern of weight gain and relapse; and others experience a deteriorating course of illness over many years.

Bulimia Nervosa

Bulimia is characterized by episodes of binge eating-eating an excessive amount of food at once with a sense of lack of control over eating during the episode-followed by behavior in order to prevent weight gain, such as self-induced purging by vomiting or misuse of laxatives, diuretics, enemas, or other medications; fasting; or excessive exercise. Because purging or other compensatory behavior follows the binge-eating episodes, people with bulimia usually weigh within the normal range for their age and height. However, like individuals with anorexia, they may fear gaining weight, desire to lose weight, and feel dissatisfied with their bodies. People with bulimia often perform the behaviors in secrecy, feeling disgusted and ashamed when they binge, yet relieved once they purge.

For more information on eating disorders, visit the National Association of Anorexia Nervosa and Associated Disorders website.

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More than 2 million Americans a year experience this disorder. It is equally common in men and women. Schizophrenia tends to appear earlier in men than in women, showing up in their late teens or early 20s as compared to their 20s or early 30s in women. Schizophrenia often begins with an episode of psychotic symptoms like hearing voices or believing that others are trying to control or harm you. The delusions - thoughts that are fragmented, bizarre, and have no basis in reality - may occur along with hallucinations and disorganized speech and behavior, leaving the individual frightened, anxious, and confused. There is no known single cause of schizophrenia. Treatment may include medications and psychosocial support like psychotherapy, self-help groups, and rehabilitation.

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