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Reliability of a family tree questionnaire for assessing family history of alcohol problems
Drug and Alcohol Dependence, 15 (1985) Elsevier Scientific Publishers Ireland Ltd.
61
61-67
RELIABILITY OF A FAMILY TREE QUESTIONNAIRE FOR ASSESSING FAMILY HISTORY OF ALCOHOL PROBLEMS*
ROBERT
E. MANN, LINDA C. SOBELL,
Addiction
Research
Foundation,
MARK B. SOBELL
33 Russell Street,
Toronto,
and DANIEL PAVAN
445s 2Sl
(Canada)
(Received August 6th, 1984)
SUMMARY
The test-retest reliability of a brief, easily administered questionnaire to assess family history of drinking problems was studied. Twenty alcoholic and twenty non-alcoholic volunteers completed the questionnaire on each of two occasions separated by about 2 weeks. The reliability of classification of first- and second-degree relatives as problem drinkers or alcoholics was examined, using both liberal and conservative diagnostic criteria. In general, both sets of criteria produced satisfactory test-retest reliability; one possible exception occurred when alcoholics’ seconddegree relatives were classified using the conservative criteria. The liberal criteria seemed to provide a more sensitive index of familial alcoholism. Key words:
Family
history
of problem
drinking
- Assessment
-
Reliability
INTRODUCTION
A knowledge of family history of alcohol problems may be an important variable in alcoholism treatment and research [l-4]. However, as Goodwin [l] has noted, assessment of family history of alcoholism presents formidable methodological problems. One difficulty is that studies utilizing familial alcoholism histories have typically gathered this information through selfreports [ 5,6]. Although corroborative data (e.g. official records, interviews with relatives) are desirable, such data are often difficult or impossible to obtain [ 71. Further, although acceptable inter-rater reliability of the diagnosis of alcoholism in relatives has been reported (based on material abstracted from family histories [ 7]), no studies have assessed the temporal
*The views expressed in this document are those of the authors and do not necessarily reflect those of the Addiction Research Foundation. 0376-8716/85/$03.30 o 1985 Elsevier Scientific Publishers Ireland Ltd. Printed and Published in Ireland
62
stability (test-retest reliability) of self-reports of familial history of alcohol problems. The present study examined the test-retest reliability of a questionnaire which assessed family history of drinking problems. The questionnaire was designed to provide subjects with a consistent set of cues for identifying relatives with drinking problems, by using a family tree diagram. Since Goodwin [ 61 has suggested that unreliability may result from less structured data collection procedures, it was hypothesized that these cues would help subjects to provide reliable information. METHOD
Subjects Twenty inpatient alcohol abusers at the Addiction Research Foundation (ARF) in Toronto and 20 non-alcoholic staff members at the ARF voluntarily participated in the study. The alcohol abusers, as compared to the nonalcoholic subjects, had a higher mean age (43.4 years vs. 34.5 years), a lower mean education (10.2 years vs. 14.2 years), and a greater proportion were married (65% vs. 55%) and male (85% vs. 55%). The alcohol abusers rep,orted a mean history of drinking problems of 11.4 years, a mean of 0.4 alcoholrelated hospitalizations, and a mean of 2.2 alcohol-related arrests. Assessment of family history of drinkingproblems Data were collected using a family tree diagram which included firstdegree (siblings, parents) and second-degree (grandparents, aunts, uncles) relatives (relatives identified as adopted or adoptive, from second marriages, or who were half- or step-siblings were excluded). Subjects coded each relative on the diagram as either (a) an abstainer - never drank; (b) a nonproblem drinker - drank but never experienced problems from drinking; or (c) a problem drinker - experienced drinking problems at some point in life. After completing the tree diagram, subjects were given a card with nine drinking-related consequences (marital problems; job problems; alcoholrelated arrests; major alcohol withdrawal symptoms. - seizures, hallucinations and/or delirium tremens; cirrhosis diagnosed by needle biopsy; inpatient or outpatient treatment for alcohol abuse; attended Alcoholics Anonymous (AA) meetings; frequent blackouts; and social disapproval by friends or parents of the relative’s drinking) and were asked to list all applicable drinking-related consequences for each relative coded as a problem drinker. Each relative identified by subjects as being a problem drinker was further evaluated by the investigators for evidence of a drinking problem. The subjects were not involved in this evaluation, and were not informed of the criteria used. For a relative to be classified as alcoholic, the subject must have indicated that the relative experienced consequences in a minimum of two of the following areas: (a) interpersonal (marital problems and/or
63
social disapproval by friends or relatives of the person’s drinking); (b) vocational; (c) legal (alcohol-related arrests); (d) physical (withdrawal symptoms, cirrhosis and/or frequent blackouts), and (e) treatment for drinking (inpatient, outpatient, AA). Procedures All subjects were given a description of the study and asked to sign a consent form. Subjects were individually interviewed at the ARF on two occasions separated by approx. 2 weeks. This 2-week interval corresponded approximately to the length of the inpatient programme, and it allowed for some flexibility in the scheduling of interviews. Subjects were told that the study was evaluating different ways of gathering information about people’s drinking behaviour and family drinking-histories and that they would be asked several questions on two different occasions. First and second interviews with subjects were counterbalanced across a male and a female interviewer, and the second interviewer was blind to the subject’s first interview answers. The second interview was identical to the first, except that the first interview required the signing of a consent form and provision of demographic and drinking-history information. The alcohol abusers (AB) were assured that their responses would be confidential, would not affect their treatment and that none of the information would be communicated to the treatment staff. All AB subjects who were approached agreed to participate in the study. All interviews were conducted when subjects were alcohol-free, as determined by breath test (one AB subject who participated in the first interview refused to take a breath test at the second interview and thus could not be interviewed; his data were excluded from the analyses). The mean number of days between the two interviews for the AB subjects was 11.2 (range = lo-14 days). The interview procedures for the non-alcoholic (NA) subjects were identical to those for the AB subjects except that the alcohol-related history questions were not asked and the breath alcohol test was not administered. Two individuals approached refused to participate. The mean number of days between the two interviews for the NA subjects was 12.9 (range = lo-20 days). RESULTS
The test-retest reliability of self-reports of family history of drinking problems was examined in two ways. First, the reliability of participants’ classifications of individual relatives as problem drinkers versus non-problem drinkers or abstainers was analysed. These analyses provided indices of reliability of classification when liberal criteria for diagnosis (i.e. subjects’ judgements of problem drinking status) were used. Second, the reliability of classification of individual relatives as alcoholics, based on applying the previously described criteria to the subjects’ reports, was evaluated. These
64
analyses provided indices of reliability when more conservative diagnostic criteria were used. The numbers of subjects in the AB and NA groups reporting any problem or alcoholic relatives in at least one of the interviews are presented in Table I; also provided are the numbers of subjects in each group who gave at least one inconsistent report (i.e. classification of a relative as a problem drinker or alcoholic in one interview but not the other). Table II summarizes the data on the reliability of subjects’ classification of relatives as problem drinkers versus non-problem drinkers or abstainers on the family tree diagram. These data clearly indicate that groups AB and NA both provided reliable classifications, with kappa values [8] ranging from 0.78 to 0.94. The lowest reliability was obtained when subjects reported on their second-degree relatives; however, the obtained kappa value is within acceptable limits. Reliability of classification of relatives as alcoholics by the investigators, based on applying to subjects’ reports the operationally defined criteria for diagnosis of alcoholism described earlier, is summarized in Table III. Again, reliabilities were high, with one exception. The kappa value for
TABLE I NUMBERS OF SUBJECTS ALCOHOL PROBLEMS
WHO REPORTED
THEY HAD RELATIVES
WHO HAD
No. of subjects who reported at least 1 problem drinker relative (liberal criteria)
No. of subjects with at least 1 inconsistent report of a problem drinker relative (liberal criteria)
No. of subjects who reported at least 1 alcoholic relative (conservative criteria)
No. of subjects with at least 1 inconsistent report of an alcoholic relative (conservative criteria)
11
2
I
2
Group AB Second-degree relatives
9
6
5
5
Group NA First-degree relatives
6
1
3
0
Group NA Second-degree relatives
6
1
3
1
Group AB First-degree relatives
65 TABLE II RELIABILITY OF CLASSIFICATION USING LIBERAL CRITERIA
OF RELATIVES
AS PROBLEM DRINKERS
Classification on T2
Classification on Tl
Problem drinker
kappa (2 SE.)
Non-problem drinker
Group AB First-degree relatives
Problem drinker Non-problem drinker
23 1
2 81
K = 0.92 f 0.05
Group AB Second-degree relatives
Problem drinker Non-problem drinker
21 3
I 155
K = 0.78 kO.07
Group NA First-degree relatives
Problem drinker Non-problem drinker
7 1
0
K = 0.93 + 0.07
85
Group NA Second-degree relatives
Problem drinker Non-problem drinker
8 1
203
0
K = 0.94 + 0.06
TABLE III RELIABILITY OF CLASSIFICATION CONSERVATIVE CRITERIA Classification on Tl
OF RELATIVES
AS ALCOHOLIC
Classification on T2 Alcoholic
Non-alcoholic
USING
kappa (+ S.E.)
Group AB First-degree relatives
Alcoholic Non-alcoholic
12 2
0 93
K = 0.91 ? 0.06
Group AB Second-degree relatives
Alcoholic Non-alcoholic
3 3
7 173
K = 0.35 + 0.20
Group NA First-degree relatives
Alcoholic Non-alcoholic
3 0
0 90
Group NA Second-degree relatives
Alcoholic Non-alcoholic
4 0
1 207
K = 1.00
K = 0.89 kO.11
66
AB subjects’ ratings of second-degree relatives is low (0.35), suggesting that classifications using these criteria may not be sufficiently reliable for research and clinical purposes in these instances. DISCUSSION These data demonstrate that both alcoholics and non-alcoholics can reliably classify relatives as alcoholics or problem drinkers over a 2-week interval. The observed kappa-values, with one exception, were within ranges acceptable for both research and clinical purposes. Previous studies have suggested that self-reports of drinking problems in family members have adequate validity [7,9,10]; the current data support that conclusion by demonstrating high levels of test-retest reliability as well. An exception to this general conclusion may be found in the reliability of classification of alcoholics’ second-degree relatives when subjects are required to indicate alcohol-related problems suffered by the relatives. The low kappa value observed suggests that adequate levels of reliability may not be obtained for these relatives. However, a large proportion of the AB group had immigrated to Canada either by themselves or with their parents, and reported little recent contact with their second-degree relatives. Thus, while they were able to classify these relatives reliably using liberal criteria, the lower level of reliability observed when the more conservative criteria were applied may have been due to the AB participants’ lack of specific knowledge about their second-degree relatives, and hence to the demographic characteristics of the sample. The question of whether conservative or liberal criteria should be used to classify relatives is one that cannot be answered directly from previous research. A major consideration when deciding which criteria to use may be the purpose for collection of family history information. Thus, liberal criteria may be suitable for identifying individuals with one or more heavy or problem drinkers in their family, while conservative criteria may be more appropriate for identifying relatives for whom there is little doubt about alcoholic status. Another consideration is the sensitivity of the measure; previous studies of family history self-reports suggest that individuals typically under-report psychiatric problems (including alcoholism) in relatives [ll]. Lower sensitivity of the conservative, as compared to the liberal, criteria is suggested by the observation that the number of identified firstdegree relatives with a drinking problem increased by about 100% when the liberal as opposed to conservative criteria were used. As well, previous literature [ 51 suggests that alcoholics or problem drinkers have significantly more relatives with drinking problems than do non-problem drinkers. In this regard, a significantly higher proportion of problem drinker first-degree relatives for the AB group was found with the liberal criteria (x: = 8.19, P < 0.05) but not with the conservative criteria (x: = 3.54, P > 0.05). Cotton [ 51 has also reported, in her review of 32 studies describing a total
67
of 3980 alcoholics and 922 non-alcoholics, that 30.8% of the parents of alcoholics were themselves alcoholics while 4.7% of the parents of nonalcoholics were alcoholics. In the present research the proportions of problem-drinking first-degree relatives obtained with the liberal criteria on the first interview concurs with Cotton’s [5] estimates (23% and 7.5% for the AB and NA groups, respectively). However, these proportions are substantially lower when the conservative criteria are applied (11.2% and 3.2% for the AB and NA groups, respectively). It appears, then, that the liberal criteria may provide a more sensitive estimate of the numbers of problem-drinking or alcoholic relatives. Research on the validity of diagnoses based on the various criteria is necessary before further estimates of sensitivity can be made. In summary, the test-retest reliability of the family tree method for assessing family history of drinking problems appears satisfactory for clinical and research purposes. A possible exception to this conclusion may occur when alcoholics’ second-degree relatives are classified using conservative criteria for diagnosis. As well, future research should examine the testretest reliability of these measures over longer periods of time. The present study examined classification of individual relatives. In many instances, family histories are assessed in order to classify the proband as family history positive or negative [ 3,121. Under these conditions, classification of probands would be as reliable, or more reliable, than the values reported here, since more general criteria are employed. Finally, the data suggest that the use of more liberal criteria for classification provides a more sensitive basis for diagnosis of relatives’ drinking problems. ACKNOWLEDGEMENTS
This work was supported, in part, by the National Health Research and Development Programme through a Postdoctoral Fellowship to the senior author. We wish to thank Mrs. Toby Levison and the staff of the Employed Problem Drinkers Programme for their assistance in recruiting subjects, and Anthony Cancilla for his assistance in data tabulation. REFERENCES 1 2 3 4 5 6 7 8 9 10 11 12
101. D.W. Goodwin, Subst. Alcohol Actions/Misuse, 1 (1980) A.I. Alterman and R.E. Tarter, J. Nerv. Ment. Dis., 171 (1983) 147. M.A. Schuckit, Biol. Psychiatry, 15 (1980) 437. B.J. Volicer et al., Drug Alcohol Depend., 12 (1983) 69. N.S. Cotton, J. Stud. Alcohol, 40 (1979) 89. D.W. Goodwin, J. Stud. Alcohol, 42 (1981) 156. 1229. N.C. Andreasen et al., Arch. Gen. Psychiatry, 34 (1977) J. Cohen, Educ. Psychol. Meas., 20 (1960) 37. J. Rimmer and D.S. Chambers, Am. J. Orthopsychiatry, 39 (1969) 760. 53. W.D. Thompson et al., Arch. Gen. Psychiatry, 39 (1982) S.B. Guze et al., Q.J. Stud. Alcohol, 24 (1963) 249. T.R. Lipscomb and P.E. Nathan, Arch. Gen. Psychiatry,
37 (1980)
576.
61
61-67
RELIABILITY OF A FAMILY TREE QUESTIONNAIRE FOR ASSESSING FAMILY HISTORY OF ALCOHOL PROBLEMS*
ROBERT
E. MANN, LINDA C. SOBELL,
Addiction
Research
Foundation,
MARK B. SOBELL
33 Russell Street,
Toronto,
and DANIEL PAVAN
445s 2Sl
(Canada)
(Received August 6th, 1984)
SUMMARY
The test-retest reliability of a brief, easily administered questionnaire to assess family history of drinking problems was studied. Twenty alcoholic and twenty non-alcoholic volunteers completed the questionnaire on each of two occasions separated by about 2 weeks. The reliability of classification of first- and second-degree relatives as problem drinkers or alcoholics was examined, using both liberal and conservative diagnostic criteria. In general, both sets of criteria produced satisfactory test-retest reliability; one possible exception occurred when alcoholics’ seconddegree relatives were classified using the conservative criteria. The liberal criteria seemed to provide a more sensitive index of familial alcoholism. Key words:
Family
history
of problem
drinking
- Assessment
-
Reliability
INTRODUCTION
A knowledge of family history of alcohol problems may be an important variable in alcoholism treatment and research [l-4]. However, as Goodwin [l] has noted, assessment of family history of alcoholism presents formidable methodological problems. One difficulty is that studies utilizing familial alcoholism histories have typically gathered this information through selfreports [ 5,6]. Although corroborative data (e.g. official records, interviews with relatives) are desirable, such data are often difficult or impossible to obtain [ 71. Further, although acceptable inter-rater reliability of the diagnosis of alcoholism in relatives has been reported (based on material abstracted from family histories [ 7]), no studies have assessed the temporal
*The views expressed in this document are those of the authors and do not necessarily reflect those of the Addiction Research Foundation. 0376-8716/85/$03.30 o 1985 Elsevier Scientific Publishers Ireland Ltd. Printed and Published in Ireland
62
stability (test-retest reliability) of self-reports of familial history of alcohol problems. The present study examined the test-retest reliability of a questionnaire which assessed family history of drinking problems. The questionnaire was designed to provide subjects with a consistent set of cues for identifying relatives with drinking problems, by using a family tree diagram. Since Goodwin [ 61 has suggested that unreliability may result from less structured data collection procedures, it was hypothesized that these cues would help subjects to provide reliable information. METHOD
Subjects Twenty inpatient alcohol abusers at the Addiction Research Foundation (ARF) in Toronto and 20 non-alcoholic staff members at the ARF voluntarily participated in the study. The alcohol abusers, as compared to the nonalcoholic subjects, had a higher mean age (43.4 years vs. 34.5 years), a lower mean education (10.2 years vs. 14.2 years), and a greater proportion were married (65% vs. 55%) and male (85% vs. 55%). The alcohol abusers rep,orted a mean history of drinking problems of 11.4 years, a mean of 0.4 alcoholrelated hospitalizations, and a mean of 2.2 alcohol-related arrests. Assessment of family history of drinkingproblems Data were collected using a family tree diagram which included firstdegree (siblings, parents) and second-degree (grandparents, aunts, uncles) relatives (relatives identified as adopted or adoptive, from second marriages, or who were half- or step-siblings were excluded). Subjects coded each relative on the diagram as either (a) an abstainer - never drank; (b) a nonproblem drinker - drank but never experienced problems from drinking; or (c) a problem drinker - experienced drinking problems at some point in life. After completing the tree diagram, subjects were given a card with nine drinking-related consequences (marital problems; job problems; alcoholrelated arrests; major alcohol withdrawal symptoms. - seizures, hallucinations and/or delirium tremens; cirrhosis diagnosed by needle biopsy; inpatient or outpatient treatment for alcohol abuse; attended Alcoholics Anonymous (AA) meetings; frequent blackouts; and social disapproval by friends or parents of the relative’s drinking) and were asked to list all applicable drinking-related consequences for each relative coded as a problem drinker. Each relative identified by subjects as being a problem drinker was further evaluated by the investigators for evidence of a drinking problem. The subjects were not involved in this evaluation, and were not informed of the criteria used. For a relative to be classified as alcoholic, the subject must have indicated that the relative experienced consequences in a minimum of two of the following areas: (a) interpersonal (marital problems and/or
63
social disapproval by friends or relatives of the person’s drinking); (b) vocational; (c) legal (alcohol-related arrests); (d) physical (withdrawal symptoms, cirrhosis and/or frequent blackouts), and (e) treatment for drinking (inpatient, outpatient, AA). Procedures All subjects were given a description of the study and asked to sign a consent form. Subjects were individually interviewed at the ARF on two occasions separated by approx. 2 weeks. This 2-week interval corresponded approximately to the length of the inpatient programme, and it allowed for some flexibility in the scheduling of interviews. Subjects were told that the study was evaluating different ways of gathering information about people’s drinking behaviour and family drinking-histories and that they would be asked several questions on two different occasions. First and second interviews with subjects were counterbalanced across a male and a female interviewer, and the second interviewer was blind to the subject’s first interview answers. The second interview was identical to the first, except that the first interview required the signing of a consent form and provision of demographic and drinking-history information. The alcohol abusers (AB) were assured that their responses would be confidential, would not affect their treatment and that none of the information would be communicated to the treatment staff. All AB subjects who were approached agreed to participate in the study. All interviews were conducted when subjects were alcohol-free, as determined by breath test (one AB subject who participated in the first interview refused to take a breath test at the second interview and thus could not be interviewed; his data were excluded from the analyses). The mean number of days between the two interviews for the AB subjects was 11.2 (range = lo-14 days). The interview procedures for the non-alcoholic (NA) subjects were identical to those for the AB subjects except that the alcohol-related history questions were not asked and the breath alcohol test was not administered. Two individuals approached refused to participate. The mean number of days between the two interviews for the NA subjects was 12.9 (range = lo-20 days). RESULTS
The test-retest reliability of self-reports of family history of drinking problems was examined in two ways. First, the reliability of participants’ classifications of individual relatives as problem drinkers versus non-problem drinkers or abstainers was analysed. These analyses provided indices of reliability of classification when liberal criteria for diagnosis (i.e. subjects’ judgements of problem drinking status) were used. Second, the reliability of classification of individual relatives as alcoholics, based on applying the previously described criteria to the subjects’ reports, was evaluated. These
64
analyses provided indices of reliability when more conservative diagnostic criteria were used. The numbers of subjects in the AB and NA groups reporting any problem or alcoholic relatives in at least one of the interviews are presented in Table I; also provided are the numbers of subjects in each group who gave at least one inconsistent report (i.e. classification of a relative as a problem drinker or alcoholic in one interview but not the other). Table II summarizes the data on the reliability of subjects’ classification of relatives as problem drinkers versus non-problem drinkers or abstainers on the family tree diagram. These data clearly indicate that groups AB and NA both provided reliable classifications, with kappa values [8] ranging from 0.78 to 0.94. The lowest reliability was obtained when subjects reported on their second-degree relatives; however, the obtained kappa value is within acceptable limits. Reliability of classification of relatives as alcoholics by the investigators, based on applying to subjects’ reports the operationally defined criteria for diagnosis of alcoholism described earlier, is summarized in Table III. Again, reliabilities were high, with one exception. The kappa value for
TABLE I NUMBERS OF SUBJECTS ALCOHOL PROBLEMS
WHO REPORTED
THEY HAD RELATIVES
WHO HAD
No. of subjects who reported at least 1 problem drinker relative (liberal criteria)
No. of subjects with at least 1 inconsistent report of a problem drinker relative (liberal criteria)
No. of subjects who reported at least 1 alcoholic relative (conservative criteria)
No. of subjects with at least 1 inconsistent report of an alcoholic relative (conservative criteria)
11
2
I
2
Group AB Second-degree relatives
9
6
5
5
Group NA First-degree relatives
6
1
3
0
Group NA Second-degree relatives
6
1
3
1
Group AB First-degree relatives
65 TABLE II RELIABILITY OF CLASSIFICATION USING LIBERAL CRITERIA
OF RELATIVES
AS PROBLEM DRINKERS
Classification on T2
Classification on Tl
Problem drinker
kappa (2 SE.)
Non-problem drinker
Group AB First-degree relatives
Problem drinker Non-problem drinker
23 1
2 81
K = 0.92 f 0.05
Group AB Second-degree relatives
Problem drinker Non-problem drinker
21 3
I 155
K = 0.78 kO.07
Group NA First-degree relatives
Problem drinker Non-problem drinker
7 1
0
K = 0.93 + 0.07
85
Group NA Second-degree relatives
Problem drinker Non-problem drinker
8 1
203
0
K = 0.94 + 0.06
TABLE III RELIABILITY OF CLASSIFICATION CONSERVATIVE CRITERIA Classification on Tl
OF RELATIVES
AS ALCOHOLIC
Classification on T2 Alcoholic
Non-alcoholic
USING
kappa (+ S.E.)
Group AB First-degree relatives
Alcoholic Non-alcoholic
12 2
0 93
K = 0.91 ? 0.06
Group AB Second-degree relatives
Alcoholic Non-alcoholic
3 3
7 173
K = 0.35 + 0.20
Group NA First-degree relatives
Alcoholic Non-alcoholic
3 0
0 90
Group NA Second-degree relatives
Alcoholic Non-alcoholic
4 0
1 207
K = 1.00
K = 0.89 kO.11
66
AB subjects’ ratings of second-degree relatives is low (0.35), suggesting that classifications using these criteria may not be sufficiently reliable for research and clinical purposes in these instances. DISCUSSION These data demonstrate that both alcoholics and non-alcoholics can reliably classify relatives as alcoholics or problem drinkers over a 2-week interval. The observed kappa-values, with one exception, were within ranges acceptable for both research and clinical purposes. Previous studies have suggested that self-reports of drinking problems in family members have adequate validity [7,9,10]; the current data support that conclusion by demonstrating high levels of test-retest reliability as well. An exception to this general conclusion may be found in the reliability of classification of alcoholics’ second-degree relatives when subjects are required to indicate alcohol-related problems suffered by the relatives. The low kappa value observed suggests that adequate levels of reliability may not be obtained for these relatives. However, a large proportion of the AB group had immigrated to Canada either by themselves or with their parents, and reported little recent contact with their second-degree relatives. Thus, while they were able to classify these relatives reliably using liberal criteria, the lower level of reliability observed when the more conservative criteria were applied may have been due to the AB participants’ lack of specific knowledge about their second-degree relatives, and hence to the demographic characteristics of the sample. The question of whether conservative or liberal criteria should be used to classify relatives is one that cannot be answered directly from previous research. A major consideration when deciding which criteria to use may be the purpose for collection of family history information. Thus, liberal criteria may be suitable for identifying individuals with one or more heavy or problem drinkers in their family, while conservative criteria may be more appropriate for identifying relatives for whom there is little doubt about alcoholic status. Another consideration is the sensitivity of the measure; previous studies of family history self-reports suggest that individuals typically under-report psychiatric problems (including alcoholism) in relatives [ll]. Lower sensitivity of the conservative, as compared to the liberal, criteria is suggested by the observation that the number of identified firstdegree relatives with a drinking problem increased by about 100% when the liberal as opposed to conservative criteria were used. As well, previous literature [ 51 suggests that alcoholics or problem drinkers have significantly more relatives with drinking problems than do non-problem drinkers. In this regard, a significantly higher proportion of problem drinker first-degree relatives for the AB group was found with the liberal criteria (x: = 8.19, P < 0.05) but not with the conservative criteria (x: = 3.54, P > 0.05). Cotton [ 51 has also reported, in her review of 32 studies describing a total
67
of 3980 alcoholics and 922 non-alcoholics, that 30.8% of the parents of alcoholics were themselves alcoholics while 4.7% of the parents of nonalcoholics were alcoholics. In the present research the proportions of problem-drinking first-degree relatives obtained with the liberal criteria on the first interview concurs with Cotton’s [5] estimates (23% and 7.5% for the AB and NA groups, respectively). However, these proportions are substantially lower when the conservative criteria are applied (11.2% and 3.2% for the AB and NA groups, respectively). It appears, then, that the liberal criteria may provide a more sensitive estimate of the numbers of problem-drinking or alcoholic relatives. Research on the validity of diagnoses based on the various criteria is necessary before further estimates of sensitivity can be made. In summary, the test-retest reliability of the family tree method for assessing family history of drinking problems appears satisfactory for clinical and research purposes. A possible exception to this conclusion may occur when alcoholics’ second-degree relatives are classified using conservative criteria for diagnosis. As well, future research should examine the testretest reliability of these measures over longer periods of time. The present study examined classification of individual relatives. In many instances, family histories are assessed in order to classify the proband as family history positive or negative [ 3,121. Under these conditions, classification of probands would be as reliable, or more reliable, than the values reported here, since more general criteria are employed. Finally, the data suggest that the use of more liberal criteria for classification provides a more sensitive basis for diagnosis of relatives’ drinking problems. ACKNOWLEDGEMENTS
This work was supported, in part, by the National Health Research and Development Programme through a Postdoctoral Fellowship to the senior author. We wish to thank Mrs. Toby Levison and the staff of the Employed Problem Drinkers Programme for their assistance in recruiting subjects, and Anthony Cancilla for his assistance in data tabulation. REFERENCES 1 2 3 4 5 6 7 8 9 10 11 12
101. D.W. Goodwin, Subst. Alcohol Actions/Misuse, 1 (1980) A.I. Alterman and R.E. Tarter, J. Nerv. Ment. Dis., 171 (1983) 147. M.A. Schuckit, Biol. Psychiatry, 15 (1980) 437. B.J. Volicer et al., Drug Alcohol Depend., 12 (1983) 69. N.S. Cotton, J. Stud. Alcohol, 40 (1979) 89. D.W. Goodwin, J. Stud. Alcohol, 42 (1981) 156. 1229. N.C. Andreasen et al., Arch. Gen. Psychiatry, 34 (1977) J. Cohen, Educ. Psychol. Meas., 20 (1960) 37. J. Rimmer and D.S. Chambers, Am. J. Orthopsychiatry, 39 (1969) 760. 53. W.D. Thompson et al., Arch. Gen. Psychiatry, 39 (1982) S.B. Guze et al., Q.J. Stud. Alcohol, 24 (1963) 249. T.R. Lipscomb and P.E. Nathan, Arch. Gen. Psychiatry,
37 (1980)
576.