Mental Illness

D

Among the Poor

Like physical diseases, the highest rates of mental illness occur among people in the lower socioeconomic classes, especially those living in severe poverty. Rates of almost all mental illnesses decline as levels of income and education increase. A national survey published in 1994 indicated that people who earned $19,000 or less annually in the United States were twice as likely to have experienced an anxiety disorder as people who earned $70,000 or more. The hardships associated with poverty seem to contribute to the development of some mental illnesses, particularly anxiety disorders and depression. In addition, debilitating mental illnesses, such as schizophrenia, may cause individuals to drift to lower socioeconomic classes.

E

Among Men and Women

Generally, the overall prevalence rates of mental illnesses among men and women are similar. However, men have much higher rates of antisocial personality disorder and substance abuse. In the United States, women suffer from depression and anxiety disorders at about twice the rate of men. The gender gap is even wider in some countries. For example, in China, women suffer from depression at nine times the rate of men.

F

Changing Rates of Mental Illness

Mental illness is becoming an increasing problem for two reasons. First, increases in life expectancy have brought increased numbers of certain chronic mental illnesses. For example, because more people are living into old age, more people are suffering from dementia. Second, a number of studies provide evidence that rates of depression are rising throughout the world. The reasons may be related to such factors as economic change, political and social violence, and cultural disruptions. While some have questioned these findings, dramatic increases in the numbers of refugees and people dislocated from their homes by economic forces or civil strife are associated with great increases in a variety of mental illnesses for those populations. According to the United Nations High Commissioner for Refugees, the number of refugees worldwide increased from 2.5 million in 1971 to 13.2 million in 1996, peaking at 17 million in 1991.

VII

Kinds of Mental Illnesses

A number of mental illnesses—such as depression, anxiety disorders, schizophrenia, and bipolar disorder—occur worldwide. Others seem to occur only in particular cultures. For example, eating disorders, such as anorexia nervosa (compulsive dieting associated with unrealistic fears of fatness), occur mostly among girls and women in Europe, North America, and Westernized areas of Asia, whose cultures view thinness as an essential component of female beauty. In Latin America, people who experience overwhelming fright after a dangerous or traumatic event are said to have susto (fright), an illness in which their soul has been frightened away. In some societies of West Africa and elsewhere, brain fag describes individuals (usually students) who experience difficulties in concentrating and thinking, as well as physical symptoms of pain and fatigue.

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Most mental health professionals in the United States use the Diagnostic and Statistical Manual of Mental Disorders(DSM), a reference book published by the American Psychiatric Association, as a guide to the different kinds of mental illnesses. The fourth edition, known as DSM-IV, describes more than 300 mental disorders, behavioral disorders, addictive disorders, and other psychological problems and groups them into broad categories. This article describes some of the major categories, including anxiety disorders, mood disorders, schizophrenia and other psychotic disorders, personality disorders, cognitive disorders, dissociative disorders, somatoform disorders, factitious disorders, substance-related disorders, eating disorders, and impulse-control disorders. Mental health professionals in many other parts of the world use a different classification system, the International Classification of Diseases (ICD), published by the World Health Organization.

The DSM and ICD are both categorical systems of classification, in which each mental illness is defined by its own unique set of symptoms and characteristics. In theory, each disorder should possess diagnostic criteria that are independent of one another, just as tuberculosis and lung cancer are discrete diseases. Yet symptoms of many mental disorders overlap, and many people—such as those who experience both depression and severe anxiety—show symptoms of more than one disorder at the same time. For these reasons, some mental health professionals advocate a dimensional system of classification. In contrast to the categorical approach, which sees mental disorders as qualitatively distinct from normal behavior, a dimensional system views behavior as falling along a continuum of normality, with some behaviors considered more abnormal than others. In a dimensional system, diagnoses do not describe discrete diseases but rather portray the relative importance of an array of symptoms.

Definitions and classifications of mental illnesses change as research improves understanding of them. For example, DSM-IV allows a diagnosis of schizophrenia only when characteristic symptoms have lasted at least one month, whereas the previous edition of DSM required a duration of only one week.

A

Anxiety Disorders

Anxiety disorders involve excessive apprehension, worry, and fear. People with generalized anxiety disorder experience constant anxiety about routine events in their lives. Phobias are fears of specific objects, situations, or activities. Panic disorder is an anxiety disorder in which people experience sudden, intense terror and such physical symptoms as rapid heartbeat and shortness of breath. People with obsessive-compulsive disorder experience intrusive thoughts or images (obsessions) or feel compelled to perform certain behaviors (compulsions). People with post-traumatic stress disorder relive traumatic events from their past and feel extreme anxiety and distress about the event.

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