Branch of psychology. It is concerned with mental and emotional disorders (e.g., neurosis, psychosis, mental deficiency) and with certain incompletely understood normal phenomena (such as dreams and hypnosis). The chief tool used in classifying psychological disorders is the American Psychiatric Assn.'s Diagnostic and Statistical Manual of Mental Disorders 4th edition (DSM-IV).
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Abnormal psychology is the interpretive and scientific study of abnormal thoughts and behavior in order to understand and correct abnormal patterns of functioning. The definition of what constitutes 'abnormal' has varied across time and across cultures, and varies among individuals within cultures. Today, persistent abnormal functioning is often associated with a mental disorder. In general, abnormal psychology can be described as an area of psychology that studies people who are consistently unable to adapt and function effectively in a variety of conditions. An individual's ability to adapt and function can be affected by a number of variables, including one's genetic makeup, physical condition, learning and reasoning, and socialization.
In the supernatural tradition, abnormal behaviors are attributed to agents outside human bodies. According to this model, abnormal behaviors are caused by demons, spirits, or the influences of moon, planets, and stars. During the Dark Ages, many Europeans believed in the power of witches, demons, and spirits. Abnormal behaviors were seen as the work of witches, demons, and spirits. People with psychological disorders were thought to be possessed by evil spirits that had to be exorcised through religious rituals. If exorcism failed, some authorities advocated steps such as confinement, beating, and other types of torture to make the body uninhabitable by witches, demons, and spirits. The belief that witches, demons, and spirits are responsible for the abnormal behavior continued into the 15th century. Swiss alchemist, astrologer, and physician Paracelsus (1493-1541) rejected the idea that abnormal behaviors were caused by witches, demons, and spirits and suggested that people’s mind and behaviors were influenced by the movements of the moon and stars.
This tradition is still alive today. Some people, especially in the developing countries and some followers of religious sects in the developed countries, continue to believe that supernatural powers influence human behaviors. However, this tradition has been largely replaced in Western academia by the biological and psychological traditions.
In the biological tradition, psychological disorders are attributed to biological causes and in the psychological tradition, disorders are attributed to faulty psychological development and to social context.
The Greek physician Hippocrates, who is considered to be the father of Western medicine, played a major role in the biological tradition. Hippocrates and his associates wrote the Hippocratic Corpus between 450 and 350 BC, in which they suggested that abnormal behaviors can be treated like any other disease. Hippocrates viewed the brain as the seat of consciousness, emotion, intelligence, and wisdom and believed that disorders involving these functions would logically be located in the brain.
These ideas of Hippocrates and his associates were later adopted by Galen, the Roman physician. Galen extended these ideas and developed a powerful and influential school of thought with in the biological tradition that extended well into the 19th century.
A more formalized response to spiritual beliefs about abnormality is the practice of exorcism. Performed by religious authorities, exorcism is thought of as another way to release evil spirits who cause pathological behavior within the person. In some instances, individuals exhibiting unusual thoughts or behaviors have been exiled from society or worse. Perceived witchcraft, for example, has been punished by death. Two Catholic Inquisitors wrote a manual, the Malleus Maleficarum, that became co-opted by many Inquisitors and witch-hunters. It contained an early taxonomy of deviant behavior and proposed guidelines for prosecuting deviant individuals.
The act of placing mentally ill individuals in a separate facility known as an asylum dates to 1547, when King Henry VIII of England established the St. Mary of Bethlehem asylum. Asylums remained popular throughout the Middle Ages and the Renaissance era.
The number of different theoretical perspectives in the field of psychological abnormality has made it difficult to properly explain psychopathology. The attempt to explain all mental disorders with the same theory leads to reductionism (explaining a disorder or other complex phenomena using only a single idea or perspective). Most mental disorders are composed of several factors, which is why one must take into account several theoretical perspectives when attempting to diagnose or explain a particular behavioral abnormality or mental disorder. Explaining mental disorders with a combination of theoretical perspectives is known as multiple causality.
The diathesis-stress model emphasizes the importance of applying multiple causality to psychopathology by stressing that disorders are caused by both precipitating causes and predisposing causes. A precipitating cause is an immediate trigger that instigates a person's action or behavior. A predisposing cause is an underlying factor that interacts with the immediate factors to result in a disorder. Both causes play a key role in the development of a psychological disorder.
A paradigm is a general viewpoint on the world and is much broader than a theory. Today's field of psychology revolves around two major paradigms for explaining mental disorders, the psychological paradigm and the biological paradigm. The psychological paradigm focuses more on the humanistic, cognitive and behavioral perspectives. The biological paradigm includes the theories that rely more on physical causes such as genetics and neurochemistry.