Mental Illness

Mental Illness, a prolonged disturbance of thought and emotion, marked by behavior not appropriate to reality. As used by most medical researchers and practitioners, the term does not include mental retardation, which means the failure to develop normal intelligence. Mental illness differs from insanity in that insanity is a legal term, not a medical one. The term applies either to certain specific types of mental illness or to severe mental retardation.


Mental Illness Terms

  • Anxiety is a condition of worry, tension, or uneasiness produced by the anticipation of some danger whose source may be largely unknown.
  • Compulsion is an irresistible impulse to perform a certain action again and again.
  • Delusion is a false belief that a person maintains in spite of evidence that proves it untrue.
  • Dementia is decreased mental ability, especially in memory and judgement, caused by conditions that destroy brain tissue.
  • Eating disorder is a condition characterized by severe disturbances in eating behavior and body image.
  • Hallucination is the perception of something that is not actually present.
  • Major depression is a mental disorder characterized by feelings of deep sadness, hopelessness, and worthlessness.
  • Mania means a mental disorder that involves extreme optimism and excessive energy, often accompanied by uncontrollable irritability and anger.
  • Mood disorder is a mental illness that mainly affects a person's mood.
  • Obsession is a recurring thought that a person considers senseless or terrible but cannot ignore.
  • Personality disorder is a condition characterized by patterns of thinking and behavior that create significant difficulties in relationships with other people.
  • Phobia means a strong, unreasonable fear of a particular object or situation.
  • Schizophrenia is a severe mental disorder characterized by psychotic symptoms, such as delusions and hallucinations. These symptoms are accompanied by a significant decline in the ability to function in many areas, including work, school, and relationships with other people.Unconscious refers to thoughts and feelings that a person is not directly or fully aware of.

Mental illness is not a single disease; the term covers a number of disorders. A mental illness may be so mild that it is unrecognized. For example, a person may suffer from constant unreasonable anxiety without realizing that the condition is abnormal or that it might be curable. Other kinds of mental illness may be so severe that the sufferer can no longer manage his or her life and requires hospitalization.

The causes of mental illness are varied and sometimes unknown. Among the numerous organic causes are imbalance of neurotransmitters, biochemical substances that facilitate nerve impulse transmission; deterioration of central nervous tissue by diseases or drugs; injury to the brain by a hard blow to the skull; and inherited emotional abnormalities.


Some kinds of mental illness result from severe emotional stress, especially if such stress occurs in infancy or early childhood. Such illnesses are called psychogenic. Many psychiatrists believe that mental illnesses are seldom entirely psychogenic, but are produced by a combination of causes. For example, manic depression and schizophrenia, which were once thought to be purely psychogenic, are now believed to be the result of severe emotional stress upon persons suffering from inherited constitutional defects.

Not only do physical factors play a part in mental illness, but mental factors can influence physical illness. A person with a psychosomatic disorder has a physical disease that is worsened or partially caused by mental factors. Such diseases include hypertension, colitis, asthma, and eczema. A person with a somatoform disorder has physical symptoms caused by mental factors, but does not actually have a physical disease.

The branch of medicine that deals exclusively with mental illness is called psychiatry. Neurologists (doctors of medicine who treat disorders of the nervous system) are concerned with the organic elements of mental illness. Psychologists and sociologists may be involved in the prevention and treatment of mental illness.

Some behavior problems of organic origin disappear with successful treatment of the cause. For example, erratic behavior caused by a brain tumor usually ends with surgical removal of the tumor. Behavior problems such as phobias or unresolved and unconscious tensions can be treated with such psychological techniques as psychoanalysis.

Most persons who suffer from mental illness can be treated without hospitalization. Those who require short-term hospitalization can be treated in most large general hospitals. State mental hospitals, private mental hospitals, and veterans' mental hospitals are equipped to give long-term treatment.

Many hospitals have programs for discharged patients that include halfway houses, where they can live for a limited time and learn basic skills before taking on an independent life, and group homes, where a small number of people live together and manage their housekeeping and cooking on their own while social workers visit regularly. Some communities have clinics that cooperate in such programs; these clinics may also treat patients with mild disorders and help prevent more serious illness.

The National Mental Health Association sponsors research on mental illness, promotes the founding of mental health clinics, and provides information about mental illness. It was formed in 1909. Headquarters are in Alexandria, Virginia.

The National Institute of Mental Health, an agency of the U.S. Public Health Service, promotes research on mental illness and provides technical assistance to other mental-health agencies. The National Alliance on Mental Illness, one of the earliest of these groups, was established in 1979.