A condition characterized by patterns of thought, emotion, or behavior that are maladaptive, disruptive, or uncomfortable either for the person affected or for others.
While psychological disorders are generally signaled by some form of abnormal behavior or thought process, abnormality can be difficult to define, especially since it varies from culture to culture. Psychologists have several standard approaches to defining abnormality for diagnostic purposes. One is the statistical approach, which evaluates behavior by determining how closely it conforms to or deviates from that of the majority of people. Behavior may also be evaluated by whether it conforms to social rules and cultural norms, an approach that avoids condemning nonconformists as abnormal for behavior that, while unusual, may not violate social standards and may even be valued in their culture. Yet another way to gauge the normality of behavior is by whether it is adaptive or maladaptive—and to what extent it interferes with the conduct of everyday life. In some situations, psychologists may also evaluate normality solely on the basis of whether or not a person is made unhappy or uncomfortable by his or her own behavior.
The official standard for the classification of psychological disorders is the American Psychiatric Association's Diagnostic and Statistical Manual of Mental Disorders, whose most recent edition is also referred to as DSM-IV. Its five dimensions, or axes for evaluating behavior and thought patterns, provide a thorough context in which to assess an individual's psychological profile. Axis I lists major mental disorders that may affect a patient. Axis II is for assessing of personality disorders—lifelong, deeply ingrained patterns of behavior that are destructive to those who display them or to others. Axis III deals with any organic medical problems that may be present. The fourth axis includes any environmental or psychosocial factors affecting a person's condition (such as the loss of a loved one, sexual abuse , divorce , career changes, poverty, or homelessness). In Axis V, the diagnostician assesses the person's level of functioning within the previous 12 months on a scale of one to 100.
Conditions that would formerly have been described as neurotic are now found in five Axis I classifications: anxiety disorders, somatoform disorders, dissociative disorders, mood disorders, and sexual disorders. Anxiety disorders—conditions involving longstanding, intense, or disruptive anxiety—are the most common of psychological disorders among Americans. These include phobias (a strong fear of a specific object or situation); generalized anxiety (a diffuse, free-floating anxiety); panic disorder (an acute anxiety attack often accompanied by agoraphobia, or fear of being separated from a safe place); and obsessive-compulsive disorder (a repetitive, uncontrollable behavior triggered by persistent, unwanted thoughts).
Somatoform disorders are characterized by psychological problems that take a physical, or somatic, form. A person suffering from a somatoform disorder will show persistent physical symptoms for which no physiological cause can be found. Included among these disorders are hypochondriasis (a strong, unjustified fear of contracting a serious disease); pain disorder (severe pain with no apparent physical cause); and somatization disorder (complaints about a variety of physical problems). Another somatoform condition, conversion disorder (formerly called conversion hysteria), is characterized by apparent blindness, deafness, paralysis, or insensitivity to pain with no physiological cause. Conversion disorders, which are most prevalent in adolescence or early adulthood, are usually accompanied by some form of severe stress and often appear to elicit surprisingly little concern in the patient. Dissociative disorders involve the fragmentation, or dissociation, of personality components that are usually integrated, such as memory , consciousness , or even identity itself. These disorders include amnesia , dissociative identity disorder , and dissociative fugue (in which amnesia is accompanied by assumption of a new identity in a new location).
Mood disorders (also called affective disorders), are characterized by extremes of mood, abnormal mood fluctuations, or inconsistency between mood and the surrounding events or environment . The two leading mood disorders are depression and bipolar disorder . Major depressive disorder is characterized by feelings and behaviors that many people experience at times—sadness, guilt , fatigue, loss of appetite—but it is distinguished by their persistence and severity. Major depression may be accompanied by feelings of inadequacy and worthlessness, weight loss or gain, sleep disturbances, difficulty concentrating and making decisions, and, in the most severe cases, delusions and suicidal impulses. Depression is a major problem in the United States; one-third of all psychiatric outpatients suffer from depression. The percentage of Americans who will experience at least one major depressive episode during their lives has been estimated at between eight and 12 percent for men and between 20 and 26 percent for women. Bipolar disorder (also known as manic depression) is characterized by the alternation of depression with mania , an abnormally active and elated emotional state in which a person becomes overly optimistic, energetic, and convinced of his or her own powers and abilities. Manic episodes can result in impulsive and unwise decisions, and may even pose physical dangers.
The DSM-IV list of mental disorders also includes psychotic disorders , which are severe conditions characterized by abnormalities in thinking, false beliefs, and other symptoms indicating a highly distorted perception of reality and severe interference with the capacity to function normally. Probably the best known of these disorders is schizophrenia , which seriously disrupts communication and other normal functions, including profound disturbances in thinking, emotion , perception, and behavior. About one percent of Americans suffer from schizophrenia. Other mental disorders listed in DSM-IV include eating and sleep disorders ; impulse control and adjustment disorders ; substance-related disorders; cognitive disorders, such as delirium , and dementia ; and disorders usually diagnosed in infancy , childhood , or adolescence, such as hyperactivity, mental retardation , and autism . Personality disorders , which are listed in Axis II of DSM-IV, include narcissistic, dependent, avoidant, and antisocial personality types. This axis also includes developmental disorders in children.