Genetic factors influencing alcohol dependence

Plentiful data from both animal and human studies support the importance of genetic influences in substance abuse and dependence (Bierut et al., 1998; Tsuang et al., 1998; Kendler et al., 2003). This review summarizes the evidence supporting such genetic influences, places them into perspective regarding animal and human studies, discusses the importance of both genes and environment, and highlights some specific genes of interest regarding the vulnerabilities for problems associated with alcohol use disorders. A long history of repetitive heavy use of alcohol exists across generations as well as the high prevalence of alcohol-related problems in Western societies. Moreover, the information offered here addresses the importance of more general issues regarding genetics and gene expression related to alcohol abuse and dependence.

A 5-year prospective evaluation of DSM-IV alcohol dependence with and without a physiological component

BACKGROUND

The DSM-III-R removed tolerance and withdrawal as required elements for a diagnosis of alcohol dependence. Although this practice was continued in DSM-IV, the more recent manual asked clinicians to note whether physiological aspects of withdrawal (tolerance and withdrawal) had ever been experienced. Few studies have determined the prognostic meaning of a history of a physiological component to DSM-IV alcohol dependence.

METHODS

Face-to-face structured interviews were used to evaluate the course of alcohol, drug, and psychiatric problems during the subsequent 5 years for 1094 alcohol-dependent men and women. These subjects had been classified into subgroups at the time of initial interview regarding evidence of tolerance or withdrawal, and all evaluations were based on DSM-IV criteria. At baseline, the application of DSM-IV diagnostic guidelines resulted in 649 (59.3%) individuals having a history of an alcohol withdrawal syndrome, with or without tolerance (group 1); 391 (35.7%) with histories of tolerance but not withdrawal (group 2); and 54 (4.9%) with no lifetime histories of tolerance or withdrawal (group 3).

RESULTS

During the 5-year follow-up, both the broad (group 1 plus 2 versus group 3) and narrow (group 1 versus group 2 plus group 3) definitions of physiological dependence were associated with more alcohol and drug problems. However, for most items, this differential primarily reflected differences between groups 1 and 3, with a less impressive effect by group 2. Although no group differences were noted for the rate of independent major depressive episodes, substance-induced depressions did differentiate among groups, a finding also most closely related to the distinction between groups 1 and 3.

CONCLUSIONS

These data support the prognostic importance of noting the presence of a physiological component in alcohol dependence and indicate the potential relevance of limiting the definition of a physiological component to withdrawal.

A five-year prospective study of diagnostic orphans for alcohol use disorders

OBJECTIVE

One consequence of the DSM-IV diagnostic system for substance abuse and dependence is that there are individuals who might endorse one or two of the criterion items for dependence but not meet criteria for abuse. These persons have been referred to as "diagnostic orphans." The aim of the analyses presented here is to further understanding about this potentially important group.

METHOD

The DSM-IV categorical approach was used to determine alcohol-related diagnoses for 439 young adult men. Structured face-to-face follow-up interviews were administered 5 years later.

RESULTS

At the beginning of the evaluation period, 14.6% (n = 64) of the men were alcohol dependent, 18.2% (n = 80) fulfilled criteria for alcohol abuse, 16.4% (n = 72) did not meet criteria for an alcohol use disorder but endorsed one or two of the dependence criteria and 50.8% (n = 223) reported none of the dependence items. At the initial interview, and again 5 years later, the diagnostic orphans reported alcohol and drug use histories that fell between the histories of those with dependence and those with no alcohol-related difficulties. The orphans were most similar to the men with abuse, although they had lower quantities and frequencies of alcohol use, endorsed fewer additional alcohol-related problems and reported less involvement with drugs compared with that group.

CONCLUSIONS

Although the diagnostic orphans were more similar to the subjects with alcohol abuse than they were to those with dependence or no diagnosis, the data do not necessarily support combining the orphans with those with abuse. These diagnostic orphans do, however, constitute an important group that carries an enhanced risk for alcohol use disorders and should be closely followed.

Mood and anxiety symptoms among 140 children from alcoholic and control families

OBJECTIVE

Children of alcoholics have been reported to have elevated levels of internalizing symptoms, including anxiety and depression. However, many studies have not adequately controlled for the influence of independent (i.e. not substance-induced) parental mood or anxiety disorders and other factors. The present evaluations assess the relationships of the family histories of alcohol use disorders and independent mood and anxiety disorders to internalizing symptoms in children of alcoholic and nonalcoholic subjects.

METHOD

A behavioral checklist and a structured interview were administered to the parents of 140 children aged 7-18 years. The fathers of these offspring had been recruited 15 years previously from a university population to participate in a prospective study of 453 men from alcoholic and nonalcoholic families.

RESULTS

While a higher score for one of four measures of internalizing symptoms in the children was found to relate to a higher density of alcoholic relatives, this pattern was more robust in children of parents with mood or anxiety disorders. In a hierarchical regression, the family history of alcohol use disorders did not add significantly to the prediction of any of the four internalizing scores in the children after considering the impact of a family history of independent mood and anxiety disorders.

CONCLUSIONS

The results indicate that internalizing symptoms in children of alcoholics were more strongly influenced by a positive family history of mood and anxiety disorders than the family history of alcohol use disorders.

A comparison of alcohol-induced and independent depression in alcoholics with histories of suicide attempts

OBJECTIVE

Alcohol-dependent men and women are at high risk for two types of major depressive episodes and for suicide attempts. The aim of this study is to compare the characteristics of two groups: (1) alcohol-dependent subjects with histories of suicide attempts and independent mood disorders and (2) a similar population of alcoholics with histories of self harm but who have only experienced alcohol-induced depressions.

METHOD

As part of the Collaborative Study on the Genetics of Alcoholism (COGA), semistructured detailed interviews were administered to 371 alcohol-dependent individuals (62% women) with histories of suicide attempts and major mood disorders. Of the total, 145 (39.1%) had ever had an independent depressive episode and 226 (60.9%) had experienced only alcohol-induced depressions. Information was obtained about socioeconomic characteristics, suicidal behavior, independent and induced psychiatric conditions, and aspects of alcohol dependence.

RESULTS

Univariate and multivariate comparisons revealed that alcohol-dependent individuals with a history of suicide attempts and independent depression had a higher number of suicide attempts, were less likely to have been drinking during their most severe attempt, and were more likely to have an independent panic disorder. Univariate analyses indicated that these subjects reported a less severe history of alcohol dependence.

CONCLUSIONS

The results indicate that a distinction between independent and alcohol-induced mood disorders in alcoholics with a history of suicide attempts may be useful.

Comparison of 3190 alcohol-dependent individuals with and without suicide attempts

INTRODUCTION

Suicidal behaviors are often seen in alcohol-dependent individuals. The aim of this study is to identify and confirm risk factors for suicide attempts in a large, family-based sample of alcoholics.

METHODS

Semistructured, detailed interviews were administered to 3190 alcohol-dependent individuals as part of the Collaborative Study on the Genetics of Alcoholism (COGA). Information about suicidal behavior, socioeconomic characteristics, psychiatric comorbidity, substance use disorders, and characteristics of alcohol dependence were obtained from alcohol-dependent probands, controls, and their relatives.

RESULTS

As determined by both univariate comparison and multivariate logistic regression analysis, alcohol-dependent individuals with a history of suicide attempts were found to have a significantly more severe course of alcohol dependence and a higher prevalence of both independent and substance-induced psychiatric disorders and other substance dependence. First-degree relatives of subjects with suicide attempts showed a significantly higher rate of suicide attempts, even after controlling for additional relevant diagnoses.

CONCLUSION

These results support the hypothesis that alcohol-dependent individuals with a history of suicide attempts are more severely impaired. Screening and subsequent treatment of alcohol use disorder, psychiatric comorbidity, and substance use disorders among alcoholics may be crucial in preventing suicide attempts and completions.

A bootstrapped commingling analysis of platelet monoamine oxidase activity levels corrected for cigarette smoking

Monoamine oxidase (MAO) activity levels have been suggested as a possible biological marker for alcohol dependence and abuse, as well as for schizophrenia and other psychiatric conditions. Using platelet MAO activities in the Collaborative Study on the Genetics of Alcoholism data set, we applied bootstrapping methods as a novel way to test for admixture in families. This bootstrapping involved resampling in family units and hypothesis testing of the resampled datasets for commingling in the distribution of MAO activity levels. Prior to commingling analysis, we used linear models to find covariates of greatest effect on MAO activity levels. While an alcoholism diagnosis was significant in men (n = 1151, P < 0.0001) and women (n = 1254, P = 0.0003), the effect lost significance after controlling for cigarette smoking, indicating alcoholism and smoking behavior to be highly confounded. When smoking histories were compared, former smokers had levels (mean = 7.1) closer to those who never smoked (mean = 7.0) than to current smokers (mean = 5.4). Furthermore, current daily smoking and time since smoking cessation were significantly related to MAO levels, indicating smoking probably has a direct effect on MAO levels, rather than the reverse. These results suggest that studies using MAO levels as a biological marker should consider smoking as an important covariate. Finally, admixture was found in MAO levels controlled for smoking and sex, possibly indicating a major genetic locus; this confirms previous evidence for admixture.

A measure of the intensity of response to alcohol in a military population

Heavy drinking and associated problems are relatively common in young men, including those in a military setting. This article explores characteristics of alcohol intake and associated difficulties and their relationship to a self-report of the usual intensity of response to alcohol in a sample of U.S. Marines. Two questionnaires related to demography and alcohol use histories, along with a simple, 12-item self-report measure of the usual number of drinks to experience an effect (the Self-Rating of the Effects of Alcohol, SRE) were administered to 1320 U.S. Marines. The sample had an average age of 22 years, 78% were Caucasian, and 92% were enlisted personnel. The relationships and correlations among drinking characteristics and problems and the usual number of drinks for an effect were determined. These subjects drank an average of 6 days per month, consuming an average of almost six drinks per drinking day, and reported more than three times per month in which they consumed six or more drinks per occasion. Consistent with studies of other populations, the SRE measures of intensity of response to alcohol showed a positive correlation with both drinking practices and problems, with the latter remaining significant even after controlling for recent drinking practices. The prodigious level of alcohol intake and associated problems, along with the SRE scores, indicate that the Marine Corps personnel are at especially high risk for alcohol-related life problems. These data also support the potential usefulness of the SRE both in identifying individuals likely to have more severe alcohol profiles and in educating individuals regarding their levels of risk for alcohol abuse and dependence.

Five-year clinical course associated with DSM-IV alcohol abuse or dependence in a large group of men and women

OBJECTIVE

The prognostic validity of the DSM-IV diagnoses of alcohol abuse and alcohol dependence was evaluated by examining the 5-year clinical course associated with those diagnoses in a large group of predominantly blue-collar men and women.

METHOD

Personal semistructured interviews were carried out 5 years after an initial evaluation with 1,346 (75%) of the approximately 1,800 men and women participating in the Collaborative Study on the Genetics of Alcoholism who were eligible for follow-up.

RESULTS

About two-thirds of the 298 subjects with DSM-IV alcohol dependence at baseline maintained that diagnosis during the 5-year study period. Fifty-five percent of the 288 subjects with DSM-IV alcohol abuse at baseline continued to meet one or more of the 11 DSM-IV abuse/dependence criteria, and 3.5% went on to meet the criteria for dependence at follow-up. Among the 760 subjects with no alcohol diagnosis at baseline, 2.5% met the criteria for alcohol dependence and 12.8% for alcohol abuse at follow-up. Baseline characteristics that predicted the occurrence of any of the 11 DSM-IV abuse/dependence criteria during the 5-year interval included male gender, lack of marital stability, presence of several of the criteria for dependence, and history of illicit drug use.

CONCLUSIONS

The data suggest that over 5 years the DSM-IV diagnosis of alcohol dependence predicts a chronic disorder with a relatively severe course, while DSM-IV alcohol abuse predicts a less persistent, milder disorder that does not usually progress to dependence.

Correlates of unpredicted outcomes in sons of alcoholics and controls

OBJECTIVE

Several risk factors for alcohol abuse and dependence have been identified, including a family history of the disorder and a low response to alcohol. However, not everyone with these attributes develops an alcohol use disorder and some alcoholics have neither characteristic. This article evaluates factors that might have contributed to unexpected outcomes, in a prospective study of sons of alcoholics and controls.

METHOD

411 men with complete data at baseline (Time 1 or T1) and at 15-year (Time 15 or T15) follow-ups were studied using the level of response (LR) to alcohol, the family history (FH) of alcoholism, and additional alcohol and drug-related experiences at T1. T15 data included the development of alcohol abuse or dependence, along with the 15-year functioning in six domains for the subject, as well as the characteristics of his spouse. The men were divided into groups based on the presence of two major risk factors, low LR and FH, after controlling for several other characteristics, including antisocial personality disorder.

RESULTS

Rates of alcohol use disorders increased across Group 1 (family history negative [FHN] and no low LR), Group 2 (either family history positive [FHP] or low LR, but not both) and Group 3 (both FHP and low LR). After controlling for FH and LR for Group 1, only T1 drinking quantity and T15 positive alcohol expectancies related to a diagnosis, but explained only 12% of the variance. The results improved to R2's of 0.26 and 0.36 for Groups 2 and 3, with additional predictors including the T1 history of alcohol problems and T15 measures of poor coping mechanisms, higher drinking in the environment and less nurturance in the social support system.

CONCLUSIONS

Procedures aimed at discouraging earlier heavier drinking, altering attitudes toward alcohol early in life, teaching appropriate coping methods and developing support systems might help individuals carrying multiple risk factors to become more resilient.

The clinical course of alcohol dependence associated with a low level of response to alcohol

AIMS

To evaluate the clinical course of specific alcohol-related life problems and the risk for dependence on illicit drugs in individuals with relatively low and high levels of response (LR) to alcohol earlier in life.

SUBJECTS

From among 439 men who were part of the 15-year follow-up of sons of alcoholics and controls, 108 were identified as having fulfilled criteria for DSM-III-R alcohol dependence.

MEASURES

The LR to alcohol was originally evaluated following the consumption of 0.61 g/kg of ethanol at age 20 by determining the levels of change in subjective feelings of intoxication, body sway and several hormones such as cortisol. From the 453 original subjects, 450 completed a face-to-face 10-year follow-up evaluation, and 439 completed the 15-year protocol.

FINDINGS

A comparison of the clinical course of 50 alcohol-dependent men with clearly low LR values at age 20 with that for 42 individuals whose LR scores were above the median revealed few differences. Those with a low LR had a slightly earlier age of onset of alcohol dependence (24.8 +/- 3.41 vs. 26.6 +/- 4.48 years), and this finding was unrelated to the presence of an alcohol-dependent father. Otherwise the members of the two groups demonstrated a similar course of alcohol dependence. There was no relationship between a low LR at age 20 and either the pattern of substances used or the rate of dependence on illicit drugs.

CONCLUSIONS

The results indicate that for this sample a low LR to alcohol, while associated with a high risk for alcohol dependence, was not related to most aspects of the course of alcohol problems once dependence developed.

A genome-wide search for genes that relate to a low level of response to alcohol

BACKGROUND

The low level of response (LR) to alcohol is genetically influenced in both humans and animals, and a low LR is a characteristic of offspring of alcoholics that has been reported to predict alcoholism 10 and 15 years later. The genes that contribute to a low LR have not yet been identified.

METHODS

A 12-item questionnaire that measures LR, the Self Rating of the Effects of Alcohol (SRE) instrument, was filled out by 745 individuals from the Collaborative Study on the Genetics of Alcoholism (COGA) for whom genetic material was available. These subjects were genotyped by using 336 markers with an average heterozygosity of 0.74 and an average intermarker distance of 10.5 cM. Both quantitative and qualitative nonparametric, sib-pair analyses were carried out for the SRE measure related to early drinking experiences.

RESULTS

Correlations of SRE scores across related individuals were significant and between 0.16 and 0.22 for most values, compared with nonsignificant correlations of 0.03 or less among unrelated individuals. Linkage analyses performed by using the FIRST 5 variables (first five times alcohol is consumed) identified four chromosomal regions with lod scores > or = 2.0 whose maximum was also near a marker. One of these chromosomal regions previously was linked to alcohol dependence in the COGA sample.

CONCLUSIONS

These data document the familial nature of a low LR to alcohol as measured by the SRE and suggest several chromosomal regions that might contribute to the phenomenon.

Genetics of the risk for alcoholism

This paper reviews the literature on the importance of genetic influences in the development of alcohol abuse and dependence (alcoholism). The alcohol use disorders are fairly typical of most complex genetic conditions in that multiple genetic influences combine together to explain approximately 40% to 60% of the risk. One useful approach for identifying specific genes related to alcoholism involves identifying a population in which known genetic factors are controlled and using genome scan and/or case-control, association approaches to search for specific genes. Several characteristics, or endophenotypes, have been identified as both genetically influenced and contributing toward the risk for alcoholism, including alcohol-metabolizing enzymes, the low level of response to alcohol, and electrophysiological measures. The potential importance of each of these characteristics is reviewed, and data relating to the search for specific genetic material for each endophenotype are presented. These findings are placed in the perspective of the impact that they are likely to have on both prevention and treatment efforts in the alcohol field.

A comparison of correlates of DSM-IV alcohol abuse or dependence among more than 400 sons of alcoholics and controls

BACKGROUND

Alcohol dependence and abuse are defined as separate disorders. However, relatively few data are available about whether the same characteristics predict both syndromes.

METHODS

Complete data were available from the 15 year follow-up of 411 men who originally had been evaluated from a university population at about age 20. Both baseline data gathered prospectively and the retrospective ratings in six domains of life functioning were analyzed for their relationship to the development of alcohol abuse or dependence during the follow-up.

RESULTS

Baseline characteristics of a family history of substance use disorders, the quantity and frequency of drinking, the history of alcohol-related problems, and the level of response to alcohol all predicted future alcohol abuse or dependence, but only an alcoholic second-degree relative or a first-degree drug-dependent family member differentially predicted dependence. Logistic regression analyses revealed that similar baseline characteristics combined to predict dependence and, separately, abuse. When the domains of functioning during the 15 years were included, positive alcohol expectancies, poor coping mechanisms, low level of social support, and drinking in the environment contributed to both dependence and abuse, although the relationship was stronger for dependence.

CONCLUSIONS

The predictors and correlates of alcohol abuse and dependence in this group of men were similar. Further research in additional populations and on other drugs is needed to determine if the two syndromes overlap sufficiently to be combined.

A preliminary evaluation of the potential usefulness of the diagnoses of polysubstance dependence

OBJECTIVE

The concept of polysubstance dependence (PD) has been defined several ways over the years. However, few clinicians and researchers appear to use this label in a manner consistent with any of the major diagnostic manuals. This article evaluates the prevalence and characteristics associated with PD in participants in a large collaborative study.

METHOD

In DSM-IV, PD characterizes people who do not meet criteria for dependence on any one substance but, when all drugs of abuse are considered have experienced three or more of the seven dependence items across the substances. In this study, structured face-to-face interviews were administered to 8,834 men and women as part of the Collaborative Study on the Genetics of Alcoholism. The 198 subjects (2.2%) with a slightly expanded concept of the DSM-IV disorder were compared with men and women with dependence on alcohol, marijuana or stimulants, subjects with substance abuse and those with no substance use disorder.

RESULTS

In this dataset, compared with subjects with a specific substance dependence, those with PD were slightly more educated and less likely to be divorced or separated, and they had fewer substance-related problems. At the same time, those with PD had more substance problems than did subjects who only met criteria for abuse. These basic conclusions were unchanged among the subset of 59 subjects who met the more restricted, classical DSM-IV PD criteria.

CONCLUSIONS

The data indicate that, while relatively rare, subjects with PD might differ in potentially important ways from those with dependence or abuse on specific drugs. A large prospective study of a group with carefully defined PD is needed.

The 5-year clinical course of high-functioning men with DSM-IV alcohol abuse or dependence

OBJECTIVE

One goal of diagnostic criteria is to predict the course of clinically relevant future problems. This study evaluated the ability of the DSM-IV categories of alcohol abuse and alcohol dependence to predict the onset and cessation of the 11 DSM-IV abuse/dependence criterion items.

METHOD

The DSM-IV categorical approach was used to determine alcohol diagnoses for 435 highly educated young adult men, who constituted 97.3% of the 447 men appropriate for this study. Structured face-to-face follow-up interviews were administered 5 years later.

RESULTS

At the beginning of the study, 14.5% (N=63) of the subjects were alcohol dependent, 18.2% (N=79) reported alcohol abuse, and 67.4% (N=293) carried no alcohol diagnosis. Across these three diagnostic groups, 68.3%, 46.8%, and 15.4%, respectively, experienced at least one of the 11 DSM-IV abuse/dependence criterion items over the next 5 years. Only 11.4% of those who reported alcohol abuse went on to develop alcohol dependence. In addition to their diagnosis, characteristics that predicted subsequent problems with alcohol included a family history of alcoholism, higher levels of alcohol intake and a greater number of alcohol problems in the 10 years preceding the diagnosis, and a history of drug use.

CONCLUSIONS

Even in this highly educated and high-functioning group of men, alcohol abuse and dependence predicted the onset and cessation of alcohol-related problems.

Behavioral symptoms and psychiatric diagnoses among 162 children in nonalcoholic or alcoholic families

OBJECTIVE

People with alcoholic relatives have high rates of alcohol abuse and dependence as adults, but their patterns of problems earlier in life are less clear. Many studies have not controlled for parental disorders other than alcoholism or for parents' socioeconomic status and general life functioning. The authors' goal was to conduct a study controlling for such factors.

METHOD

Personal structured interviews and a behavioral checklist were administered to the parents of 162 children 7 years old or older whose fathers had participated in the 15-year follow-up of 453 sons of alcoholics with no history of antisocial personality disorder and sons of nonalcoholic comparison subjects originally selected from a university population.

RESULTS

There was no significant relationship between a family history of alcoholism and childhood diagnoses of conduct, oppositional, or attention deficit disorders or with behavioral checklist summary scores. However, children with alcoholic relatives apparently have a slightly higher risk for drug abuse or dependence than those without alcoholic relatives.

CONCLUSIONS

Once familial antisocial disorders and familial socioeconomic status are controlled for, a family history of alcoholism does not appear to relate to childhood externalizing disorders.

The relationships of a family history of alcohol dependence, a low level of response to alcohol and six domains of life functioning to the development of alcohol use disorders

OBJECTIVE

Numerous biological and sociocultural factors have been proposed as potentially important to the risk for alcohol use disorders. This study evaluates the relationships to alcohol abuse or dependence of several additional potential trait and state characteristics when studied in the context of a family history of alcohol dependence (FH) and the level of response (LR) to alcohol.

METHOD

Data were generated from the successful 15-year follow-up of 97% of 453 sons of alcohol dependent men and controls; of these, 315 men were appropriate for the current analyses. Personal interviews were used to gather data from the subjects and additional informants to study the relationships among FH, LR as determined 15 years previously, and retrospective ratings over the recent 15 years for six additional domains of life functioning. These were evaluated as correlates of a diagnosis of an alcohol use disorder in both a 3-step hierarchical and a 7-step structured series of regressions for the subjects with complete data.

RESULTS

LR, FH and measures from all of the domains except stress had significant zero-order correlations with alcohol abuse or dependence. The hierarchical regression revealed that LR and FH remained significant when considered in the context of the five remaining domains. Both trait-like characteristics (behavioral undercontrol, alcohol expectancies and ways of coping) and state-like domains (nurturance in the social support system and the amount of drinking in the environment) added significantly to the analyses. A heuristic model of the relationship among these variables was tested in a structured series of regressions with a final R2 of 0.22. Future prospective study of the offspring of these subjects will help evaluate potential causal implications of these findings.

CONCLUSIONS

Prospective studies, measuring both biological and environmental factors, are needed for optimal understanding of the performance of such characteristics in real-life conditions.

Clinical characteristics and family histories of alcoholics with stimulant dependence

OBJECTIVE

While much is known about the clinical patterns and family histories of individuals with alcoholism or stimulant (cocaine and amphetamine) dependence, there are few data that describe men and women with concomitant alcohol and stimulant dependence.

METHOD

As part of the Collaborative Study on the Genetics of Alcoholism, structured interviews were administered to 3,882 (2,432 male) DSM-III-R defined alcohol and/or stimulant dependent subjects. The characteristics and family histories of four groups were compared: Group 1 (26%), with the onset of alcohol before stimulant dependence; Group 2 (10%), with alcohol dependence simultaneously with or after stimulant dependence; Group 3 (58%), with alcohol dependence only; Group 4 (6%), with stimulant dependence only.

RESULTS

Individuals with concomitant alcohol and stimulant dependence (Groups 1 and 2) reported more general life problems (e.g., marital instability), a higher rate of antisocial personality disorder and more substance-induced mood disorders, additional drug dependencies and substance-related difficulties than those with dependence on one substance only. People with alcohol dependence before stimulant dependence had the most severe clinical patterns. In addition, alcohol dependence and stimulant dependence were found to breed true in families of subjects with these concomitant disorders. The major findings were confirmed with logistic regression analyses, and were independent of ASPD and gender.

CONCLUSIONS

It is important for clinicians to be aware of the severe clinical characteristics of patients with concomitant alcohol and stimulant dependence. In addition, the data consistent with drug-specific heritability in this heterogeneous population may be useful to researchers.

Response to alcohol in daughters of alcoholics: a pilot study and a comparison with sons of alcoholics

Drinking, but not alcohol-dependent, 18-29-year-old daughters of alcoholics (n = 38) from the Collaborative Study on the Genetics of Alcoholism were compared to 75 family-history-positive (FHP) men from the same families, and 68 family-history-negative (FHN) male controls. Subjects received 0.75 ml/kg of ethanol (for women), 0.9 ml/kg of ethanol (for men), and placebo, each of which was consumed over 8 min on different occasions. The breath-alcohol concentrations (BrAC) and reactions to alcohol [using the Subjective High Assessment Scale (SHAS) and body sway measures] were evaluated over 210 min. The results indicate that, despite slightly higher BrAC values for the FHP men, on the SHAS the FHP women and the FHP men demonstrated significantly lower scores than the FHN male controls, although the values for FHP men and women did not differ. On body sway, the FHP men showed evidence of less alcohol-related increases than FHN men, and there was a trend in the same direction for FHP women, but only early in the session (e.g. at 60 min). Pilot data for 11 FHN women revealed higher scores for both SHAS and body sway at 60 min, compared to FHP women, but, perhaps reflecting the small number of subjects, the family history differences were not significant. Overall, the results in FHP women resemble those for FHP men, and suggest that a low level of response to alcohol might also be a characteristic of daughters of alcoholics.

Family-based study of the association of the dopamine D2 receptor gene (DRD2) with habitual smoking

A recent study showed an association between the dopamine D2 receptor gene (DRD2) and smoking. The purpose of this study was to determine if the familial transmission of smoking is linked to variation at the DRD2 locus in a genetically informative sample. Subjects were identified in alcohol treatment centers and their relatives were recruited for study. All subjects were interviewed to assess alcohol dependence, smoking habits, and psychiatric disorders. Two polymorphisms within the DRD2 gene were analyzed, including the TaqIA polymorphism. The sample consisted of 138 nuclear families with at least one offspring with habitual smoking, and analysis was by the transmission disequilibrium test (TDT), which avoids problems due to population stratification. There was no significant difference in the frequency between DRD2 alleles transmitted and not transmitted to habitual smokers. There also was no evidence for unequal transmission of DRD2 alleles for the phenotypes "ever smoker" or comorbid alcohol dependence and habitual smoking. This study does not support linkage of the DRD2 with smoking.

A latent class analysis of antisocial personality disorder symptom data from a multi-centre family study of alcoholism

AIMS

To determine if there are subtypes of Antisocial Personality Disorder (ASPD), as manifested by distinctive symptom profiles or by associations with alcohol, other drug dependence or other psychiatric disorders.

METHODS

Data on 38 symptoms of ASPD (including childhood conduct disorder) obtained from probands, their relatives and controls (2834 females and 3488 males) recruited for the Collaborative Study on the Genetics of Alcoholism (COGA) were analyzed using latent class analysis. Associations of the resulting latent classes with alcohol dependence (AD) and other psychiatric disorders were examined.

FINDINGS

Among women, a 4-class solution was obtained in which conduct disorder and ASPD were found almost exclusively in the most severely affected class with two additional classes with mild and moderate behavior problems also identified. A strong linear trend (p < 0.001) for AD was observed, with each successive class manifesting a higher prevalence than the previous class. Milestones of drinking careers and dependence on other drugs also showed a strong association with class severity. Among men, a 5-class solution was obtained and, like women, the highest prevalence of ASPD (74.6%) was found in the most severely affected class. Somewhat unexpected was the observation that prevalence of AD was equivalent in the two most severe classes. The data for men indicated a class with a milder spectrum of childhood misbehaviors but with an adult ASPD profile--as well as other psychiatric co-morbidity--that was comparable to the most severe class.

CONCLUSIONS

Overall, findings from both men and women did not support the existence of subtypes of ASPD, but rather indicated a disorder distributed on a severity spectrum.

Clinical correlates of cigarette smoking and nicotine dependence in alcohol-dependent men and women. The Collaborative Study Group on the Genetics of Alcoholism

This paper examines the clinical characteristics associated with tobacco use and nicotine dependence in a large sample of alcohol-dependent subjects. The goal was to determine if the characteristics of the alcohol use history were associated with the smoking status, even after controlling for additional characteristics, such as the antisocial personality disorder, other drug dependence and gender. As part of the Collaborative Study on the Genetics of Alcoholism, a semi-structured interview, including a detailed history of alcohol and tobacco use, was administered to 1005 alcohol-dependent men and women, made up of 658 (65.5%) current smokers, 167 (16.6%) former smokers, and 180 (17.9%) non-smokers. Among former smokers, 50.3%, and among current smokers, 72.8% had ever been nicotine-dependent (DSM-III-R). Current smokers and nicotine-dependent subjects had a greater severity of alcohol dependence, even as evaluated through logistic regression analyses in which gender and associated diagnoses were considered. The data also enabled us to study the relationships among depression, nicotine dependence, and alcohol dependence, with most of the correlation occurring for substance-induced, not independent, mood disorders.

Family-based study of the association of the dopamine D2 receptor gene (DRD2) with habitual smoking

A recent study showed an association between the dopamine D2 receptor gene (DRD2) and smoking. The purpose of this study was to determine if the familial transmission of smoking is linked to variation at the DRD2 locus in a genetically informative sample. Subjects were identified in alcohol treatment centers and their relatives were recruited for study. All subjects were interviewed to assess alcohol dependence, smoking habits, and psychiatric disorders. Two polymorphisms within the DRD2 gene were analyzed, including the TaqIA polymorphism. The sample consisted of 138 nuclear families with at least one offspring with habitual smoking, and analysis was by the transmission disequilibrium test (TDT), which avoids problems due to population stratification. There was no significant difference in the frequency between DRD2 alleles transmitted and not transmitted to habitual smokers. There also was no evidence for unequal transmission of DRD2 alleles for the phenotypes "ever smoker" or comorbid alcohol dependence and habitual smoking. This study does not support linkage of the DRD2 with smoking.

Co-occurring risk factors for alcohol dependence and habitual smoking

Smoking and alcohol dependence frequently occur together, and both behaviors are determined in part by genetic influences. The Collaborative Study on the Genetics of Alcoholism (COGA), which is investigating the genetic factors contributing to alcohol dependence, also allows for analyses of the genetic factors determining smoking. Using a sample comprised of alcoholics and their closest (i.e., first-degree) relatives as well as a community-based control sample, COGA investigators found that both alcohol dependence and habitual smoking were transmitted within families. This familial transmission resulted from both common and drug-specific influences, which likely include genetic factors. Further genetic studies (i.e., candidate gene studies and genomic screening approaches) have identified several DNA regions that may contain genes that confer a susceptibility for alcoholism. Some of those genes also may contribute to the risk for habitual smoking.

Impact of a stimulant-focused enhanced program on the outcome of alcohol- and/or stimulant-dependent men

BACKGROUND

The approaches to the treatment of most forms of substance dependence are similar. It is not clear whether specific treatment components need to be added to address specific substances. This study asks two questions: What is the impact of a more intense drug treatment program, and do different substance problems require different treatment interventions?

METHODS

The 383 veterans included in this study represent two groups of consecutive inpatient male admissions with current alcohol dependence and/or dependence on amphetamines or cocaine at the inpatient Alcohol and Drug Treatment Program of the Veterans Affairs San Diego Healthcare System. All were interviewed at intake by trained interviewers using a standardized semistructured assessment instrument, and a resource person interview also was conducted with 85% of them. The first group of men received the Standard Treatment Program (STP), whereas the second group received the Enhanced Treatment Program (ETP). The latter included an addition of 10 hr per week of intense treatment aimed at stimulants, including two newly developed manual-driven groups (Relapse Prevention and Interpersonal Counseling), each of which met twice a week.

RESULTS

The patient follow-up was 92% at 3 months and 83% at 12 months. Abstinence from substances of abuse for ETP and STP were 63% vs. 49% at 3 months and 43% vs. 24% at 12 months. Logistic regressions demonstrated that treatment type continued to predict outcome even in the context of other potentially predictive variables.

CONCLUSIONS

Despite the ETP emphasis on stimulants, both alcohol- and stimulant-dependent men appeared to benefit, suggesting a generic improvement in substance use.

Evaluation of the self-rating of the effects of alcohol form in Asian Americans with aldehyde dehydrogenase polymorphisms

OBJECTIVE

In order to easily assess individual differences in response to alcohol, the Self-Rating of the Effects of Alcohol (SRE) form was recently developed and its psychometric properties tested in primarily white subjects. This study aimed to further evaluate the SRE in a population known to have genetically mediated variability in response to alcohol and risk for alcoholism, Asian Americans with ALDH2 polymorphisms.

METHOD

Men and women of Chinese, Japanese or Korean heritage between the ages of 21 and 26 years (N = 156) completed the SRE and a blood sample was drawn for genotyping at the ALDH2 locus.

RESULTS

SRE results were available from 137 (78 female) subjects. With the effects of gender, body weight, frequency of recent drinking and quantity of recent drinking controlled, ALDH2 genotype still accounted for a significant amount of variability in SRE score in this Asian-American sample. Evaluation of SRE scores 4.5 or higher indicated that a low response to alcohol was associated with ALDH2*1/2*1 genotype, male gender and Korean heritage, all factors associated with increased risk for alcoholism.

CONCLUSIONS

These results provide additional support for the SRE as a valid instrument for assessing individual variability in response to alcohol and as a useful measure for identifying individuals at relatively increased or decreased risk for alcoholism based on level of reaction to alcohol.

Clinical characteristics of alcoholism in alcohol-dependent subjects with and without a history of alcohol treatment

BACKGROUND

Most clinical alcohol research is carried out on alcoholics who are in treatment, usually inpatients. However, most alcohol-dependent men and women never enter treatment, and even fewer ever receive inpatient care. Thus, some generally accepted data on the clinical course of alcoholism, derived from treatment samples, might not generalize to the entire population of alcohol-dependent individuals. This article characterizes the clinical characteristics of alcohol dependence in three groups of alcoholics, based on their histories of treatment for alcohol problems: those without prior rehabilitation; those with only outpatient approaches or Alcoholics Anonymous (AA); and subjects with an inpatient experience.

METHODS

Semistructured interviews were administered to 3572 DSM-III-R-defined alcohol-dependent subjects from the Collaborative Study on the Genetics of Alcoholism. The clinical patterns were compared across the three groups of alcoholics: Group 1, never-treated (n = 1582; 44%); Group 2, histories of outpatient or AA only (n = 399; 11%); and Group 3, at least one inpatient experience (n = 1591; 45%).

RESULTS

A progression was shown from Groups 1 to 3 for more general life problems (e.g., unemployment, marital instability); higher rates of additional drug dependencies and psychiatric disorders; and more alcohol-related adverse events. Logistic regression analyses revealed that those with no prior treatment were more likely to be women, Caucasian, and employed, and to report a lower rate of divorce/separation, lower levels of alcohol intake, and fewer alcohol problems. Among those who received help, inpatient care was predicted by an opposite profile.

CONCLUSIONS

These results indicate that studies using data from inpatient populations may give a skewed picture of the clinical characteristics of alcohol dependence.

How would you label your own drinking pattern overall? An evaluation of answers provided by 181 high functioning middle-aged men

The self-rating of drinking habits was compared to DSM-III-R diagnoses of alcohol abuse and dependence in 181 men with an average age (+/- SD) of 38.7 +/- 1.91 years. Results indicate that the 150 subjects without alcohol-related diagnosis (Group 1) rated themselves as 'non-problem drinker', in categories from 'non-drinker' to 'heavy drinker'. Among the 15 individuals with alcohol abuse (Group 2), none rated their drinking pattern as 'problem drinker'. Two (12.5%) subjects in the group of 16 individuals with alcohol dependence (Group 3) rated themselves as 'problem drinker', while most did not consider their drinking patterns as problematic. Within subjects who identified themselves as the same type of drinker (e.g. 'infrequent drinker', 'moderate drinker', etc ...), the quantity, frequency, and number of alcohol-related problems were higher in Groups 2 and 3, compared to Group 1. The self-rating of drinking habits using a single question failed to identify over 90% of the subjects diagnosed with alcohol use disorder (100% of those with alcohol abuse and 87.5% of those with alcohol dependence), and did not differentiate between levels of alcohol intake and number of alcohol-related problems for subjects who identified as a particular drinking type.

Characteristics of alcohol dependent subjects with very elevated levels of Gamma-Glutamyltransferase (GGT)

OBJECTIVE

This article examines characteristics of a subgroup of alcohol dependent men with very elevated serum Gamma-Glutamyltransferase (GGT) activity.

METHOD

GGT was measured in 196 men soon after admission to an inpatient alcohol and drug treatment program. Subjects were split into two groups based on the a priori GGT value of > or =150 U/L for Group 1 (n = 20), and <150 U/L for Group 2 (n = 176). Serum aspartate amino-transferase (AST), serum alanine amino-transferase (ALT) and mean corpuscular volume (MCV), as well as several aspects of the drinking history, were compared cross-sectionally between the two groups. The stability of GGT in the context of drinking was evaluated prospectively over 12 months in a subsample of 35 individuals.

RESULTS

Most measures of the drinking pattern and severity of dependence were similar between the two groups, although subjects in Group 1 demonstrated higher levels for AST (p < .01), MCV (p < .01) and ALT (p < .01). Subjects in Group 1 reported more drinking days per month (23.8 +/- 3.98 vs 17.8 +/- 8.71, t = 5.43, p < .001), and more related history of alcoholic liver disease (30.0% vs 8.5%, chi2 = 8.66, p < .01). In the presence of the variables significantly different between the two groups, AST, the number of drinking days per month and the proportion with alcoholic liver disease predicted membership to Group 1, although their influence was moderate (pseudo R between 0.16 and 0.20). The correlation between GGT at intake and follow-up in 35 individuals who returned to drinking was r = .56, p < .001, while two out of three subjects with high GGT at intake were also high at follow-up.

CONCLUSIONS

Subjects with very high GGT seem to demonstrate a more intense vulnerability to alcohol, a characteristic which appears to be stable over time.

Selective genotyping for the role of 5-HT2A, 5-HT2C, and GABA alpha 6 receptors and the serotonin transporter in the level of response to alcohol: a pilot study

BACKGROUND

The vulnerability to alcohol dependence appears to be genetically influenced through a variety of mechanisms. One potentially genetically mediated channel may be a low level of response (LR) to alcohol, which has been seen in children of alcoholics and noted to predict future alcohol abuse and dependence. This pilot study uses a case and control genetic association approach to evaluate the possible role of five genotypes in both LR and alcoholism in informative subgroups of men with high and low LR scores documented 15 years earlier.

METHODS

As part of a larger study, 41 men, about 39 years old, were selected from among the first 113, completed 15-year follow-ups in a prospective study. The 17 subjects whose LRs at age 20 were in the lower third were compared on five polymorphisms of four genes with 24 men whose reactions to alcohol had been above the median.

RESULTS

The 14 men with the LL genotype of the serotonin transporter (5-HTT) polymorphism and the seven with the Pro/Ser genotype of the GABAA alpha 6 polymorphism had demonstrated lower LR scores at about age 20, and had significantly higher proportions of alcoholics than the other genotypes for those loci. All four subjects with combined LL and Pro/Ser genotypes had developed alcoholism and demonstrated the lowest LR scores overall. There was no evidence that two polymorphisms of the 5-HT2A receptor gene and one of the 5-HT2C receptor gene were related to LR or alcoholism in this sample.

CONCLUSIONS

These results are consistent with animal and human studies suggesting a possible role for genetic variation in the GABAA alpha 6 and the serotonin transporter in the reaction to alcohol and the alcoholism risk.

Clinical implications for four drugs of the DSM-IV distinction between substance dependence with and without a physiological component

OBJECTIVE

The DSM-IV work group asked researchers and clinicians to subtype substance dependent individuals according to the presence or absence of physiological symptoms. A recent report from the Collaborative Study on the Genetics of Alcoholism demonstrated that among alcohol-dependent men and women, a history of tolerance or withdrawal was associated with a more severe clinical course, especially for individuals with histories of alcohol withdrawal. This article evaluates similar distinctions among subjects in the collaborative study who were dependent on marijuana, cocaine, amphetamines, or opiates.

METHOD

Structured interviews gathered information from 1,457 individuals with a lifetime diagnosis of marijuana dependence, 1,262 with histories of cocaine dependence, 647 with amphetamine dependence, and 368 subjects with opiate dependence. For each drug, the clinical course was compared for subjects whose dependence included a history of withdrawal (group 1), those dependent on each drug who denied withdrawal but reported tolerance (group 2), and those who denied both tolerance and withdrawal (group 3).

RESULTS

The proportion of dependent individuals who denied tolerance or withdrawal (group 3) ranged from 30% for marijuana to 4% for opiates. For each substance, individuals in groups 1 and 2 evidenced more severe substance-related problems and at least a trend for greater intensities of exposure to the drug; those reporting withdrawal (group 1) showed the greatest intensity of problems.

CONCLUSIONS

The designation of dependence in the context of tolerance or withdrawal identifies individuals with more severe clinical histories. These results support the importance of the designation of a physiological component to dependence, especially for people who have experienced a withdrawal syndrome.

Familial transmission of substance dependence: alcohol, marijuana, cocaine, and habitual smoking: a report from the Collaborative Study on the Genetics of Alcoholism

BACKGROUND

Alcoholism and substance dependence frequently co-occur. Accordingly, we evaluated the familial transmission of alcohol, marijuana, and cocaine dependence and habitual smoking in the Collaborative Study on the Genetics of Alcoholism.

METHODS

Subjects (n=1212) who met criteria for both DSM-III-R alcohol dependence and Feighner definite alcoholism and their siblings (n=2755) were recruited for study. A comparison sample was also recruited (probands, n=217; siblings, n=254). Subjects were interviewed with the Semi-Structured Assessment for the Genetics of Alcoholism. The familial aggregation of drug dependence and habitual smoking in siblings of alcohol-dependent and non-alcohol-dependent probands was measured by means of the Cox proportional hazards model.

RESULTS

Rates of alcohol, marijuana, and cocaine dependence and habitual smoking were increased in siblings of alcohol-dependent probands compared with siblings of controls. For siblings of alcohol-dependent probands, 49.3% to 50.1% of brothers and 22.4% to 25.0% of sisters were alcohol dependent (lifetime diagnosis), but this elevated risk was not further increased by comorbid substance dependence in probands. Siblings of marijuana-dependent probands had an elevated risk of developing marijuana dependence (relative risk [RR], 1.78) and siblings of cocaine-dependent probands had an elevated risk of developing cocaine dependence (RR, 1.71). There was a similar finding for habitual smoking (RR, 1.77 in siblings of habitual-smoking probands).

CONCLUSIONS

Alcohol, marijuana, and cocaine dependence and habitual smoking are all familial, and there is evidence of both common and specific addictive factors transmitted in families. This specificity suggests independent causative factors in the development of each type of substance dependence.

Alcohol dependence and mood disorders

This article explores the complex relationships between alcohol dependence and mood disorders. Although many alcoholics present with substance-induced depressions, once appropriate methodological controls are used, there does not appear to be a significant relationship between independent unipolar depression and alcohol dependence. However, the data support a small, but significant, relationship between bipolar manic-depressive disease and alcoholism. The literature does not support the relevance of self-medication as a course of alcoholism, unless one includes the use of alcohol to alleviate alcohol-induced psychological and neurochemical perturbations. The clinical importance of distinguishing between substance-induced and independent mood disorders is reviewed.

Influence of age and body mass index on gamma-glutamyltransferase activity: a 15-year follow-up evaluation in a community sample

Most clinicians and researchers view serum gamma-glutamyltransferase (GGT) activity as a measure that can be interpreted equally in patients regardless of their demography. The present study evaluates the concurrent influence of age and body mass index (BMI) on GGT in a sample of 133 high functioning young men, with detailed assessment of the pattern of alcohol use at ages 20 [time 1 (T1)], 30 [time 2 (T2)], and 35 [time 3 (T3)]. GGT increased between T1 and T2 (15.4 +/- 9.65 units/liter vs. 20.1 +/- 12.07 units/liter, t = 4.17, p < 0.001), and between T2 and T3 (20.1 +/- 12.07 units/liter vs. 27.3 +/- 24.69 units/liter, t = 4.11, p < 0.001). Controlling for drinking quantity and frequency did not change the finding. The relationship between GGT and BMI was estimated after splitting the sample into normal (BMI < or = 25 kg/m2) and overweight (BMI > 25 kg/m2) subjects. The correlation between GGT and BMI in normal weight men at T1 was r = 0.15, p = 0.09, at T2 r = 0.00, p = 0.96, and at T3 r = 0.09, p = 0.09. In overweight subjects, correlation at T1 was r = 0.40, p = 0.20, at T2 r = 0.36, p < 0.05, and at T3 r = 0.44, p < 0.001. Controlling for the effect of alcohol consumption and/or age did not alter these conclusions. Testing for the interaction of age, BMI, and alcohol consumption did not yield relevant results. We concluded that GGT is positively related to age in the 20s to late 30s and to BMI in overweight subjects; both relationships of age and BMI were independent of alcohol consumption. The interpretation of GGT should take age and BMI into account when suspecting subclinical alcohol problems in young men.

The clinical course of alcohol-related problems in alcohol dependent and nonalcohol dependent drinking women and men

OBJECTIVE

This article examines the differences in the clinical course of alcohol dependence in men and women, interpreting results in light of the gender differences in nonalcoholics and potential findings from the general population.

METHOD

As part of the Collaborative Study on the Genetics of Alcoholism (COGA) protocol, a detailed semistructured interview was administered to 1,085 alcohol dependent women and 2,120 alcohol dependent men, along with 1,936 women and 1,233 men who were drinkers but not alcoholic. Subjects were alcohol dependent probands, controls, and relatives of each.

RESULTS

The men's and women's rank orders of alcohol-related life events were similar for alcohol dependent subjects, with a rho (rho) of .95, a figure that remained constant even when only primary alcoholics were considered. In general, those items for which the two genders evidenced differences in either the mean age of occurrence or the proportion of people who experienced an event were similar to gender differences in drinking among nonalcoholics or the literature on the general population. These included for women a lower maximum number of drinks per day, a 1- to 2-year later onset of several early alcohol-related problems and fewer years between the onset of problems and seeking help. Female alcoholics also showed a lower proportion with legal, job or personal problems related to alcohol. There were also high levels of similarity (p = .76, p > .001) for 28 life events related to alcohol for 1,936 women and 1,233 men who were drinkers but not alcohol dependent.

CONCLUSIONS

Overall, the time course of alcohol-related problems for men and women were more similar than different. While there was evidence of a "telescoping" of the time between the onset of problems and treatment for women, the gender differences in ages of onset of events were relatively small. These data support the conclusion that, after considering gender differences in drinking in society, there is little evidence that the natural history of alcohol dependence in women is substantially different than in men.

Biological, psychological and environmental predictors of the alcoholism risk: a longitudinal study

OBJECTIVE

This article reviews results from an ongoing prospective study of 453 sons of alcoholics and controls, and presents new data from the 15-year follow-up.

METHOD

Drinking, but not alcohol dependent, 20-year-old sons of alcoholics and controls were evaluated for their level of response (LR) to alcohol and were subsequently followed, through personal interviews, 10 years and 15 years later.

RESULTS

The 10-year follow-up of 450 (99.3%) men and provisional analyses from the first 127 subjects at 15 years revealed that a low LR at about age 20 predicted subsequent alcoholism, even after considering the original quantity and frequency of drinking and six additional domains of influence. Regarding the latter, behavioral undercontrol and work stress appear to interact with LR, with alcohol expectancies, coping mechanisms and aspects of the drinking in the environment also appearing to add to the model, while other aspects of life stress and the social support network do not.

CONCLUSIONS

The prospective evaluation of subjects at higher risk for alcoholism is a potentially powerful tool in identifying the relationships among a broad range of moderators and mediators of the alcoholism risk. The present tentative results based on the first 127 subjects are primarily heuristic as findings might change in the full sample. These data set the stage for completion of the 15-year follow-up and for a subsequent 20-year evaluation which will focus on the same domains in the projected almost 560 sons and daughters of the original sample.

Clinical relevance of the distinction between alcohol dependence with and without a physiological component

OBJECTIVE

DSM-IV indicates that diagnoses of substance dependence should be further characterized with regard to the presence of a physiological component, defined by tolerance or withdrawal. This study evaluated the possible meaning of this distinction in alcohol-dependent men and women.

METHOD

As part of the Collaborative Study on the Genetics of Alcoholism, structured interviews were carried out with 3,395 DSM-III-R-defined alcohol-dependent individuals divided into 2,949 subjects (86.9%) with evidence of tolerance and/or withdrawal (group 1), 51.3% of whom evidenced withdrawal symptoms, and 446 subjects (13.1%) without a physiological component (group 2). Data were evaluated to determine differences between the two groups.

RESULTS

Group 1 reported greater severity of alcohol dependence as demonstrated by a larger maximum number of drinks in 24 hours, more persons reporting binges, more alcohol-related life problems, more relevant DSM-III-R criteria endorsed, more physiological complications, and more alcohol-related emotional/psychiatric symptoms such as depression and anxiety. Each of these severity indicators for problems in group 1 was significant in the presence of the others in a logistic regression, and similar items remained significant when tolerance alone, withdrawal alone, or their combination was used as the criterion for group 1 membership; however, for withdrawal a larger proportion of the variance was explained by the predictor variables. The regression results were independent of gender, proband status, and history of antisocial personality disorder.

CONCLUSIONS

The results support the clinical relevance of distinguishing between alcohol-dependent patients with and without a physiological component. The data indicate a potential advantage to limiting that definition to withdrawal only.

Genome-wide search for genes affecting the risk for alcohol dependence

Alcohol dependence is a leading cause of morbidity and premature death. Several lines of evidence suggest a substantial genetic component to the risk for alcoholism: sibs of alcoholic probands have a 3-8 fold increased risk of also developing alcoholism, and twin heritability estimates of 50-60% are reported by contemporary studies of twins. We report on the results of a six-center collaborative study to identify susceptibility loci for alcohol dependence. A genome-wide screen examined 291 markers in 987 individuals from 105 families. Two-point and multipoint nonparametric linkage analyses were performed to detect susceptibility loci for alcohol dependence. Multipoint methods provided the strongest suggestions of linkage with susceptibility loci for alcohol dependence on chromosomes 1 and 7, and more modest evidence for a locus on chromosome 2. In addition, there was suggestive evidence for a protective locus on chromosome 4 near the alcohol dehydrogenase genes, for which protective effects have been reported in Asian populations.

Platelet monoamine oxidase activity in subgroups of alcoholics and controls: results from the Collaborative Study on the Genetics of Alcoholism

OBJECTIVE

Platelet monoamine oxidase (MAO) B activity levels were evaluated to determine whether low platelet MAO activity is a marker for alcoholism, correlates of alcoholism (e.g., cigarette smoking), or a subtype of alcoholism.

METHODS

Adult women (n = 788) and men (n = 685) participating in the Collaborative Study on the Genetics of Alcoholism study were evaluated with a semistructured interview, and blood samples were obtained for determination of platelet MAO activity using tryptamine (0.1 mM) as substrate. DSM-III-R alcohol-dependent individuals were subgrouped using four currently available methods (e.g., two variations of the type 1/type 2 scheme, primary versus secondary typology, type A/type B dichotomy).

RESULTS

In the overall sample, subjects' gender, cigarette smoking status, and the Collaborative Study on the Genetics of Alcoholism site at which their platelets were prepared explained 22% of the variance in platelet MAO activity levels, and multivariate analysis showed that carrying a broad diagnosis of alcohol dependence did not uniquely explain any additional variance in platelet MAO activity levels. Furthermore, within each of the alcoholic subgrouping methods tested, there were no significant differences in platelet MAO activity for type 1 versus type 2, type A versus type B, or primary versus secondary alcoholics.

CONCLUSIONS

Cigarette smoking and male gender are associated with decreased platelet MAO activity levels. After considering these factors, a diagnosis of alcohol dependence does not predict any additional variance in MAO-B activity. Phenotypes of alcoholics (e.g., type 1 versus type 2, type A versus type B, primary versus secondary) do not differ in platelet MAO activity. The results suggest that decreased platelet MAO activity is not a trait marker of alcoholism or one of its subtypes; but, rather, is a state marker of cigarette smoking.

Quantitative trait loci analysis of human event-related brain potentials: P3 voltage

The P3 event-related brain potential (ERP) is a positive-going voltage change of scalp-recorded electroencephalographic activity that occurs between 300-500 ms after stimulus onset. It is elicited when a stimulus is perceived, memory operations are engaged, and attentional resources are allocated toward its processing. Because this ERP component reflects fundamental cognitive processing, it has found wide utility as an assessment of human mental function in basic and clinical studies. In particular, P3 attributes are heritable and have demonstrated considerable promise as a means to identify individuals at genetic risk for alcoholism. We have conducted a quantitative linkage analysis on a large sample from families with a high density of affected individuals. The analyses suggest that several regions of the human genome contain genetic loci related to the generation of the P3 component of the ERP, which are possible candidate loci underlying the functional organization of human neuroelectric activity.

Periods of abstinence following the onset of alcohol dependence in 1,853 men and women

OBJECTIVE

Data from both laboratory experiments and retrospective histories of alcoholics indicate that alternations between periods of abstinence and heavy drinking are common in the course of alcoholism. This article examines the prevalence, chronological characteristics and clinical features associated with periods of abstinence in a large sample of alcohol dependent men and women.

METHOD

As part of the Collaborative Study on the Genetics of Alcoholism (COGA), semistructured personal interviews were used to gather data on the course of alcoholism in 1,853 alcohol dependent men and women. Data were evaluated regarding the characteristics of alcoholics with and without periods of abstinence lasting 3 or more months, and the course of these periods over time were evaluated separately for subjects with one, two, three or four episodes of abstention.

RESULTS

Despite a relatively high threshold of 3 months for defining an abstinence period, 62.3% of the subjects had at least one such episode, including 55.6% of the 1,853 alcoholics for whom complete data were available. Those alcohol dependent subjects with periods of abstention had an average (+/- SD) of 1.7 +/- 0.99 such periods, and 43% of abstainers had two or more. Logistic regression analyses revealed that the predictors of history of abstention were female gender (odds ratio [OR] = 1.78), older age at interview (OR = 1.04 per year), younger age of onset of alcoholism (OR 0.93 per year), ever having been married (OR = 1.45), the number of DSM-III-R dependence items endorsed (OR = 1.03 per item) and attendance in AA (OR = 2.82). Among abstainers, a period lasting 5 or more years was predicted by older age (OR = 1.03 per year) and AA participation (OR = 3.23), but also by more years of alcoholism (OR = 1.06 per year), white racial background (OR = 1.79) and the absence of history of having been a proband (OR = 3.39).

CONCLUSIONS

Periods of abstinence of 3 or more months were commonly observed in the course of alcohol dependence. This information is important for clinicians who need to avoid inappropriate stereotypes of alcoholism and who wish to educate their alcohol dependent patients about the course of this disorder.

The life-time rates of three major mood disorders and four major anxiety disorders in alcoholics and controls

AIMS

While psychiatric symptoms are common in the general population and even more prevalent in alcoholics, their clinical implications are not clear. The goal of this study was to establish the life-time rates of several independent and concurrent mood and anxiety disorders in alcoholics, controls and their relatives.

DESIGN

Structured interviews were administered to alcoholics entering treatment, their relatives, and controls.

SETTING

The study was carried out in six different centers in the United States as part of the Collaborative Study on the Genetics of Alcoholism (COGA).

PARTICIPANTS

Data were gathered from 2713 alcohol dependent subjects (probands and their alcoholic relatives) and 919 controls.

MEASUREMENTS

The timeline-based Semi-Structured Assessment for the Genetics of Alcoholism (SSAGA) interview was administered face to face by trained, closely supervised interviewers. The life-time rates for concurrent and independent disorders were determined for three DSM-III-R major mood and four major anxiety disorders.

FINDINGS

Some form of independent mood disorder was seen during the life-time in slightly fewer alcoholics than controls (14.0% and 17.1%), but alcoholics did show higher rates of independent bipolar disorder (2.3% vs. 1.0%). The life-time rate for independent anxiety disorders was significantly higher in alcoholics than controls (9.4% vs. 3.7%), with most of the differential related to panic disorder (4.2% vs. 1.0%) and social phobia (3.2% vs. 1.4%), but no significant group differences for agoraphobia or obsessive-compulsive disorder. In general, these findings regarding mood and anxiety disorders were reflected in close relatives.

CONCLUSIONS

The large majority of alcohol-dependent men and women in this sample did not have any of the independent mood or anxiety disorders evaluated here. However, there was evidence of enhanced risks among alcoholics for independent bipolar, panic and social phobic disorders. Studies which do not distinguish carefully between independent and concurrent mood and anxiety disorders in alcoholics are likely to report much higher rates of co-morbid psychiatric disorders than those that distinguish between the two types of syndromes.