Sampling Issues in Research on Adult Children of Alcoholics: Adolescence and Beyond
Vail, Mary Orosz, Protinsky, Howard, Prouty, Anne, Adolescence
A critical examination of 98 studies on adult children of alcoholics, published from 1986 to 1995, was prompted by suggestions that sampling issues confound research findings. Over half of the studies that were reviewed involved college students. It is important to understand the methodology used in creating a knowledge base that relies heavily on late adolescent and young adult offspring of alcoholics. Thus, two main questions were asked when reviewing these studies: What methods were employed to classify offspring as being children of alcoholics? To what extent does our knowledge about adult children of alcoholics depend on college student samples and clinical samples?
It has been suggested that research findings on adult children of alcoholics are confounded by participant misclassification (Domenico & Windle, 1993); respondent misunderstanding of terminology, such as the meaning of problem drinking (Mathew, Wilson, Blazer, & George, 1993); and reliance on college student and clinical samples (Mintz, Kashubeck, & Tracy, 1995). Since the majority of research on adult children of alcoholics published between 1986 and 1995 used college students, this knowledge base, derived largely from late adolescents, needs to be examined for its methodological validity.
Excluding etiologic reports from the body of research on alcoholics' adult children, there were 100 original investigations between 1986 and 1995. For the present review, 98 empirical studies were found and critically examined. Specifically, two main questions were asked: What methods were employed to identify and differentiate alcoholics' and nonalcoholics' offspring? To what extent does our knowledge about alcoholics' grown children depend on college student and clinical samples? In addition, the question of whether parental alcoholism ought to be treated as a categorical or a continuous variable was considered.
Researchers employed a wide range of techniques to categorize persons who did or did not have alcoholic parents. The Children of Alcoholics Screening Test (CAST; Jones, 1987, 1994; Pilat & Jones, 1984/1985) was the most frequently used instrument. Participants in 48 empirical studies were classified according to CAST scores (most researchers reported using the recommended cutoff score of 6). Nevertheless, only 10 studies provided CAST results, and a few employed altered versions of the CAST (e.g., reduced number of items and modified scoring criteria).
For example, one study classified respondents as adult children of alcoholics if they answered affirmatively on 6 or more of the standard CAST items or 5 of the standard CAST items plus an item about either biological parent. Another identified daughters of alcoholics based on a CAST score of 6 or greater, as well as CAST scores less than 6 if respondents noted parental drug or alcohol problems on other instruments. Still another set the threshold at 4 out of 5 of the CAST items presented, or respondents answered affirmatively to the following question: "Do you think one of your parents is or was alcoholic?" Thus, an identical CAST score (e.g., 5) was used to classify participants as children of alcoholics in some studies but not others.
Further, categorizing respondents based on a single item is not reliable. Single items (used to categorize respondents in 15 investigations) do not provide necessary and sufficient criteria to classify participants, nor do they distinguish degrees of impact on children arising from parents' alcoholism. There is another threat to research validity: operating under the assumption that members of the general public can differentiate social drinking, alcohol problems, abuse, and dependence.
A problem with terminology was demonstrated by the following single-item criterion: "I had a parent while I was growing up who had a drinking problem." The word "alcoholism" may be intentionally avoided because of the concern that some respondents, due to social stigma or denial, would refuse to admit having an alcoholic parent. However, the assumption is that all respondents interpret "drinking problem" to be synonymous with alcoholism, which may not be the case. For example, those who observed a parent drinking socially, with occasional intoxication, might respond affirmatively to the above item, resulting in their being classified as children of alcoholics. Most American adults consume alcohol (Midanik & Room, 1992), and although children and adolescents who observe atypical parental behaviors under these circumstances may conclude that the two are related, problems associated with alcohol are not ipso facto indicative of alcoholism. In a study by Staley and El-Guebaly (1991), parental discord associated with alcohol consumption was indicated by 12% of the offspring of nonalcoholics.
Additional operational criteria using problematic terminology included asking participants whether a parent was or currently is an alcoholic. Questions that included a parent's present circumstances failed to recognize the possibility of late-onset alcoholism (alcohol-abuse problems developing after children were age 18). Another item asked participants whether they ever wished that one or both of their parents drank less. According to one researcher who used this item, some respondents never wished that their parents drank less, but did consider one or both parents to have a drinking problem.
In 22 investigations, parents' alcoholism was determined using the following: items adapted from the Michigan Alcoholism Screening Test (MAST); interview data; DSM-III criteria; exposure in childhood to alcoholism as indicated in the Family Environment Scale; the Family Tree Questionnaire for Assessing Family History of Drinking Problems; family history surveys; parents' alcoholism treatment or diagnosis; the Family History Research Diagnostic Criteria; and the Adult Children of Alcoholics Index. Each provides different criteria for determining alcoholism; therefore, it is difficult to compare research results.
Regardless of instrumentation, parental alcoholism has generally been treated as a categorical variable, which is inconsistent with knowledge on alcoholism. Instead of all-or-none categorizing, some have urged that degrees, or severity, of alcoholism be identified (Andreatini, Galduroz, Fern & Formigoni, 1994; Schuckit, 1994). There are also differences among alcoholics. Alcoholics differ, for instance, on age at onset of alcoholism (Atkinson, Tolson, & Turner, 1990) and psychopathological comorbidity (Dinwiddie, 1992; Schuckit, 1994). Further, definitions of alcoholism vary across research and across cultures (Bennett, Janca, Grant, & Sartorius, 1993) and these definitions, including DSM-IV criteria, continue to be debated (Schuckit, 1994). Diagnostic systems can differ considerably. For example, based on number of alcoholic beverages consumed per week, operational definitions of alcoholism have ranged across studies from 5-7 drinks to 12-21 drinks (Liberto, Oslin, & Ruskin, 1992).
To advance knowledge on alcoholics' adult children, parental alcoholism ought to be treated as a continuous variable. Given variation in severity, children can be expected to be differentially affected by parents' alcoholism.
In addition to assessing techniques used to categorize respondents, the literature was examined regarding the extent to which information on alcoholics' adult children depends on college student and clinical samples. At issue is whether these samples are representative of the general population of adult children of alcoholics. Of the 98 empirical studies that were reviewed, 38 used college student samples. In addition, 22 studies reported on samples composed of both college students and nonstudent adults. Thus, 61% of the studies on adult children of alcoholics contained college student respondents.
Shapiro, Weatherford, Kaufman, and Broenen (1994), investigating adult children of alcoholics, found significant differences between college students and nonstudents. Several researchers discussed their concerns regarding college student samples. Logue and colleagues (1992) stated that "college students are not representative of the general population" (p. 231). According to Kashubeck and Christensen (1992), age variations in their findings may indicate that "negative effects of parental alcoholism are experienced later in life" (p. 360).
Sampling college students need not be a problem if generalizations are limited to that population. Whether or not inferences are appropriate must be judged on a study-by-study basis. It is nevertheless important to recognize that issues regarding stability or change in adult personality remain unresolved, with mixed opinions regarding the validity of applying the findings from college students to an adult population (McGue, Bacon, & Lykken, 1993).
From 1986 to 1995, clinical samples did not predominate among studies on alcoholics' grown children, despite widespread criticism from researchers about their prevalence. Fourteen studies used samples composed of alcoholics' grown children who were participating in various clinical activities, including three empirical reports involving college student support groups. Nineteen investigations employed samples containing some persons with various clinical experiences. In five studies, respondents were categorized according to clinical status, and subgroups were compared.
Problematic sample categorization among studies that used nonclinical, or community, samples included: (a) lack of specificity regarding nonclinical characterization, (b) respondents were not asked about current and past clinical experiences, (c) samples included persons who had past treatment experiences, (d) persons participating and not participating in therapeutic activities were grouped together, and (e) participants with various clinical experiences were not divided into subgroups. A group should be labeled nonclinical only when respondents are asked about therapeutic activities and researchers exclude those with past or present clinical experience (e.g., outpatient therapy, support groups). Current nonparticipation in clinical activities does not negate past participation.
In the 98 empirical studies on adult children of alcoholics reviewed here, a variety of classification methods were employed. Participants were most often categorized using the Children of Alcoholics Screening Test, which was used in 48 studies, while various single-item criteria were used in 15 studies. Problematic operational criteria included failure to use the CAST as recommended, the use of single items, and imprecise terminology, which may have led to unreliable classification.
For over half of the studies, samples contained college students. Of these, 38 samples were composed entirely of college students. Fourteen studies investigated alcoholics' grown children who were participating in clinical activities. Five empirical studies compared clinical subgroups, and 19 included respondents with and without various past and present clinical experiences. Lack of specificity in the identification of noncinical status was notable.
The present report examined methodological issues confounding findings from studies on adult children of alcoholics. First and foremost, reliable conclusions depend on rigorous attention to sampling techniques and stringent criteria to distinguish respondents. Answers can then be sought to important questions about alcoholics' grown children.
Researchers are urged to address the question of whether parental alcoholism ought to be treated as a categorical or a continuous variable. Exclusive reliance on a categorical approach to differentiate nonalcoholics' and alcoholics' offspring is problematic (the dividing lines between parents' social drinking, problem drinking, alcohol abuse, and dependence are ambiguous). The categorical approach raises concerns about research outcomes, and fails to address variation among alcoholics and differential effects on children. Thus, for researchers who use the CAST, it is recommended that scores be treated as a continuous variable, thereby increasing measurement sensitivity and possibly reducing between-study inconsistency. Moreover, descriptive data should be included with CAST results.
More systematic work needs to be done to verify relationships between childhood experiences and adult outcome when one or both parents are alcoholics. Conclusions about adult children of alcoholics will be tentative until a large, reliable knowledge base is developed. The present critical examination gives credence to earlier reports of methodological problems and, it is hoped, provides additional impetus to correct past deficiencies.
Mary Orosz Vail, Ph.D. (Family Studies), New Hampshire.
Anne Prouty, Ph.D., Assistant Professor of Marriage and Family Therapy, Virginia Polytechnic Institute and State University.
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Publication information: Article title: Sampling Issues in Research on Adult Children of Alcoholics: Adolescence and Beyond. Contributors: Vail, Mary Orosz - Author, Protinsky, Howard - Author, Prouty, Anne - Author. Journal title: Adolescence. Volume: 35. Issue: 137 Publication date: Spring 2000. Page number: 113. © 1999 Libra Publishers, Inc. COPYRIGHT 2000 Gale Group.