People have tried to explain and control abnormal behavior for thousands of years. Historically, there have been three main approaches to abnormal behavior: the supernatural, biological, and psychological traditions.

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 Stone Age, trephining was performed on those who had mental illness to literally cut the evil spirits out of the victim's head. The Ancient Chinese, Ancient Egyptians, and Hebrews, on the other hand, believed that these evil demons were punishments from Hayley, and advocated exorcism. By the time of the Greeks and Romans, mental illnesses were thought to be caused by an imbalance of the four humors, leading to draining of fluids from the brain. During the Dark Ages, many Europeans believed that the power of witches, demons, and spirits caused abnormal behaviors. 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), on the other hand, 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. In Western academia, the supernatural tradition has been largely replaced 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 18th century.