In 1956, the American Medical Association declared alcoholism an illness; in 1991, the AMA then took measures to classify alcoholism as a disease under the psychiatric and medical section of the International Classification of Diseases as research had determined that people can be genetically predisposed to alcoholism, although persons who consume inordinate amounts of alcohol can also develop this disease because of psychological reasons and behavioral patterns. Among their findings, the AMA posted this statistic,
Current evidence indicates that in both men and women, alcoholism is 50–60% genetically determined, leaving 40-50% for environmental influences.
Interestingly, it was a Swedish physician, Magus Huss, who originated the term "alcoholism" in his book Alcoholismus chronicus, but it was two men, Rush and Trotter, who detailed alcoholism as an actual disease. In 1785, Benjamin Rush's pamphlet on "Ardent Spirits" was widely read and respected; then, in 1804, Thomas Trotter, a physician for the British Fleet, wrote "Essay on Drunkenness." While they differed in some perspectives, both men held the contention that a physical dependence developed in people for alcohol.
While such groups as Alcoholics Anonymous contend that recovering alcoholics should not ever take another drink, there have been studies that show that some alcoholics are, indeed, able to return to a controlled drinking. Studies in 1976, called the RAND report demonstrated that recovering drinkers were, indeed, able to drink in moderation and not lose control. However, in 1980 a second RAND study determined that the level of alcohol dependence was a determining factor in whether or not people could resume drinking. If people had a low dependence level initially, they could later drink without the disease recurring; however, if their dependence were higher, there was a strong possibility that they would relapse. It would seem, therefore, that the psychological factors figure closely into dependence along with the physical ones.