context: Nearly 5 million children in the U. S. have some type of serious mental illness (one that significantly interferes with daily life). In any given year, 20% of American children will be diagnosed with a mental illness. The term "mental illness" is not entirely accurate, because there are many "physical" factors -- including heredity and brain chemistry -- that might be involved in the development of a mental disorder. As such, many mental disorders can be effectively treated with medication, psychotherapy (a type of counseling), or a combination of both. Identifying mental disorders in children can be tricky for health care providers. Children differ from adults in that they experience many physical, mental, and emotional changes as they progress through their natural growth and development. They also are in the process of learning how to cope with, adapt, and relate to others and the world around them. Furthermore, each child matures at his or her own pace, and what is considered "normal" in children falls within a wide range of behavior and abilities. For these reasons, any diagnosis of a mental disorder must consider how well a child functions at home, within the family, at school, and with peers, as well as the child's age and symptoms. There are several different types of mental disorders that can affect children and adolescents, including: Anxiety disorders: Children with anxiety disorders respond to certain things or situations with fear and dread, as well as with physical signs of anxiety (nervousness), such as a rapid heartbeat and sweating. Attention-deficit/hyperactivity disorder ( ADHD): Children with ADHD generally have problems paying attention or concentrating, can't seem to follow directions, and are easily bored and/or frustrated with tasks. They also tend to move constantly and are impulsive (do not think before they act). Disruptive behavior disorders: Children with these disorders tend to defy rules and often are disruptive in structured environments, such as school. Pervasive development disorders: Children with these disorders are confused in their thinking and generally have problems understanding the world around them. Eating disorders: Eating disorders involve intense emotions and attitudes, as well as unusual behaviors associated with weight and/or food. Elimination disorders: Disorders that affect behavior related to using the bathroom. Enuresis, or bed-wetting, is the most common of the elimination disorders. Learning and communication disorders: Children with these disorders have problems storing and processing information, as well as relating their thoughts and ideas. Affective (mood) disorders: These disorders involve persistent feelings of sadness and/or rapidly changing moods, and include depression and bipolar disorder. A more recent diagnosis is called disruptive mood dysregulation disorder, a childhood and adolescent condition involving chronic or persistent irritability and frequent angry outbursts. Schizophrenia: This disorder involves distorted perceptions and thoughts. Tic disorders: These disorders cause a person to perform repeated, sudden, involuntary (not done on purpose), and often meaningless movements and sounds, called tics. Some of these disorders, such as anxiety disorders, eating disorders, mood disorders and schizophrenia, can occur in adults as well as children. Others begin in childhood only, although they can continue into adulthood. It is not unusual for a child to have more than one disorder. Symptoms in children vary depending on the type of mental illness, but some of the general symptoms include: Abuse of drugs and/or alcohol Inability to cope with daily problems and activities Changes in sleeping and/or eating habits Excessive complaints of physical ailments Defying authority, skipping school, stealing, or damaging property Intense fear of gaining weight Long-lasting negative moods, often accompanied by poor appetite and thoughts of death Frequent outbursts of anger Changes in school performance, such as getting poor grades despite good efforts Loss of interest in friends and activities they usually enjoy Significant increase in time spent alone Excessive worrying or anxiety Hyperactivity Persistent nightmares or night terrors Persistent disobedience or aggressive behavior Hearing voices or seeing things that are not there (hallucinations) The exact cause of most mental disorders is not known, but research suggests that a combination of factors, including heredity, biology, psychological trauma, and environmental stress, might be involved. Heredity (genetics): Many mental disorders run in families, suggesting that the disorders, or more accurately, a vulnerability to the disorders, might be passed on from parents to children through genes. Biology: As in adults, many mental disorders in children have been linked to abnormal functioning of particular brain regions that control emotion, thinking, perception, and behavior. Head traumas also can sometimes lead to changes in mood and personality. Psychological trauma: Some mental disorders might be triggered by psychological trauma, such as severe emotional, physical, or sexual abuse; an important early loss, such as the loss of a parent; and neglect. Environmental stress: Stressful or traumatic events can trigger a disorder in a person with a vulnerability to a mental disorder. As with adults, mental disorders in children are diagnosed based on signs and symptoms; however, diagnosing mental illness in children can be especially difficult. Many behaviors that are seen as symptoms of mental disorders, such as shyness, anxiety (nervousness), strange eating habits, and outbursts of temper, can occur as a normal part of a child's development. Behaviors become symptoms when they occur very often, last a long time, occur at an unusual age, or cause significant disruption to the child's and/or family's life. If symptoms are present, the doctor will begin an evaluation by performing a complete medical and developmental history and physical exam. Although there are no lab tests to specifically diagnose mental disorders, the doctor might use various diagnostic tests, such as neuroimaging and blood tests, to rule out physical illness or medication side effects as the cause of the symptoms. If no physical illness is found, the child may be referred to a child and adolescent psychiatrist or psychologist, health care professionals who are specially trained to diagnose and treat mental illness in children and teens. Psychiatrists and psychologists use specially designed interview and assessment tools to evaluate a child for a mental disorder. The doctor bases a diagnosis on reports of the child's symptoms and observation of the child's attitude and behavior. The doctor often must rely on reports from the child's parents, teachers, and other adults, because children often have trouble explaining their problems or understanding their symptoms. The doctor then determines if the child's symptoms point to a specific mental disorder. Mental illnesses are like many medical disorders, such as diabetes or heart disease, that require ongoing treatment. Although much progress has been made in the treatment of adults with mental disorders, the treatment of children is not as well understood. Experts are still exploring which treatments work best for which conditions in children. For now, many of the treatment options used for children, including many medications, are the same as those used in adults but with different dosing. The most common treatment options used include: Medication: The drugs often used to treat mental disorders in children include antipsychotics, antidepressants, anti-anxiety drugs, stimulants, and mood stabilizing drugs. Psychotherapy: Psychotherapy (a type of counseling often simply called therapy) addresses the emotional response to mental illness. It is a process in which trained mental health professionals help people deal with their illness, often by talking through strategies for understanding and dealing with their symptoms, thoughts, and behaviors. Types of psychotherapy often used with children are supportive, cognitive-behavioral, interpersonal, group, and family therapy. Creative therapies: Certain therapies, such as art therapy or play therapy, might be helpful, especially with young children who might have trouble communicating their thoughts and feelings. Different medications have different side effects, and some children are not able to tolerate certain drugs. Although the medications approved by the FDA to treat mental disorders in children are generally considered safe, the doctor might need to change drugs or dosages to minimize side effects. It may take some trial and error to find the medications that work best for an individual child. Without treatment, many mental disorders can continue into adulthood and lead to problems in all areas of the person's adult life. People with untreated mental disorders are at high risk for many problems, including alcohol or drug abuse, and (depending on the type of disorder) violent or self-destructive behavior, even suicide. When treated appropriately and early, many children can fully recover from their mental disorder or successfully control their symptoms. Although some children become disabled adults because of a chronic or severe disorder, many people who experience a mental illness, such as depression or anxiety, are able to live full and productive lives. To date, most research on mental illness has centered on adults. However, the mental health community has now begun to focus on mental illness in children. Researchers are looking at childhood development in terms of what is normal and abnormal, trying to understand how factors affecting development can have an impact on mental health. The goal is to try to predict, and ultimately, prevent, developmental problems that could lead to mental illness. A key part of this research is the identification of risk factors that increase a child's chances of developing a mental disorder. In addition, the mental health community is calling for additional research on medications used to treat children with mental disorders. Most mental disorders are caused by a combination of factors and cannot be prevented. However, if symptoms are recognized and treatment is started early, many of the distressing and disabling effects of a mental disorder may be prevented or at least minimized.