Prospective studies of children of alcoholic parents.

Alcoholism tends to run in families: Compared with children of nonalcoholics (non-COA's), children of alcoholic parents (COA's) have an approximately four times greater risk of becoming alcoholic themselves (West and Prinz 1987; Cotton 1979; Merikangas et al. 1985). The causal factors underlying the development (i.e., the etiology) of alcohol abuse and dependence. however, have not yet been conclusively determined. Studies conducted in the 1950's and 1960's generally emphasized psychosocial explanations, such as poor parenting, lack of good role models, and impoverished home life. Research performed since the 1970's, however, also has investigated heritable components in the familial transmission of alcoholism. Adoption studies (Goodwin et al.1973; Cadoret et al. 1985,1987; Cloninger et al. 1981), analyses of half-siblings (Schuckit et al. 1972), and studies comparing identical (i.e., monozygotic) and fraternal (i.e., dizygotic) twins (Heath and Martin 1988; Heath et al. 1991; Kendler et al. 1992; McGue et al. 1992) have all provided evidence that genetic factors play a crucial role in the etiology of alcoholism. Despite this strong evidence for a genetic contribution, few researchers would deny the influence of environmental factors in the development of alcoholism. The term "environmental" refers here to all factors that do not directly contribute to the genetic risk for alcoholism, whether they act in the prenatal period, early childhood, or early or late adolescence. Examples of such variables include maternal drinking during pregnancy, temperament and personality traits of the parents and children, psychopathology in the parents and children, geographic location, family and community environment, religious involvement, academic failure, and association with deviant peers. Because some of these factors (e.g., psychopathology) also have a genetic component, they may indirectly increase the genetic predisposition for alcoholism in some COA's. A major task in determining the etiology of alcoholism is to closely examine the interaction among the various environmental and genetic factors that determine a child's pathway toward or away from alcoholism. Most likely, numerous such pathways exist, although only a limited number of critical variables may affect most of them (Sher 1994). The identification of these variables may help researchers distinguish "at-risk" populations that should be targeted for research and interventions aimed at prevention. To determine critical risk factors for alcoholism, particularly among COA's, scientists have employed several study designs, including retrospective, cross-sectional, and prospective studies. Retrospective and Cross-Sectional Studies Most of the information on the developmental pathways leading to alcoholism comes from retrospective or crosssectional studies. Retrospective studies gather pertinent information about the subjects' past based primarily on self-reports by the study participants. This information includes, for example, the age at which the subjects began to drink, the level and frequency of alcohol consumption, and the presence of certain types of psychopathology (e.g., depression and antisocial personality disorder [ASPD]). Although retrospective studies have yielded important information, the interpretation of these data often is limited because the subjects' recall may not always be accurate. For example, although most study participants are able to report on their youth or young adulthood, they may forget certain events that occurred in the past or mistake the order in which the events occurred (e.g., whether the onset of depression preceded or followed the onset of alcohol problems). At least in some alcoholic subjects, these recall problems may be caused or aggravated by memory deficits resulting from long-term alcohol abuse. Cross-sectional studies assess the subjects at one point in time. This method is useful in adults to determine traits that appear to be linked to alcoholism. …