Drinking course through midlife based on diagnostic versus quantity-frequency indices.

BACKGROUND: Prior efforts to examine the course of drinking from onset to midlife have been limited to analyses of year-to-year changes in alcohol dependence (AD). The current investigation sought to examine the course of drinking over this time frame using consumption-based measures of drinking and evaluate the degree of comparability in trajectories estimated from diagnostic and quantity-frequency data. METHODS: Participants included 420 men with a lifetime history of AD who were drawn from the Vietnam Era Twin Registry and administered the Lifetime Drinking History, which provided person-year (retrospective) data on patterns of consumption and diagnostic symptoms from drinking onset to participants' current age. Consumption-based data were aggregated into age categories that ranged from "up to age 20" to "ages 54 to 56" and analyzed separately as a dichotomous measure of "heavy drinking (HD)" and continuous quantity-frequency index (QFI) scores. RESULTS: Using latent growth mixture modeling, trajectories based on the HD measure were moderately concordant with those based on changes in AD that were previously identified in this sample, whereas trajectories based on QFI scores were only weakly related to those based on AD diagnoses. Moreover, examination of the degree of concordance between AD- and QFI-derived trajectories revealed that measures of consumption (and potentially other continuous indices of drinking) may qualify past interpretations of various developmental trajectories that have been discussed in the alcoholism typology literature (particularly "Late Onset" alcoholism). CONCLUSIONS: Collectively, the findings highlight the importance of integrating repeated measures of alcohol consumption in future efforts to describe the course of drinking across the life span.

A latent class analysis of DSM-IV and Fagerström (FTND) criteria for nicotine dependence.

BACKGROUND: Nicotine dependence is associated with considerable morbidity and mortality. Two predominant classification systems, the Diagnostic and Statistical Manual (DSM-IV) and Fagerström Test for Nicotine Dependence (FTND), have been used to measure liability to nicotine dependence, yet few studies have attempted to simultaneously examine both sets of criteria. METHODS: Using a sample of 624 regular smoking individuals who are offspring of Vietnam Era Twin fathers ascertained for an offspring of twin study, we applied latent class analysis to the 7 DSM-IV and the 6 FTND criteria to classify individuals by their nicotine dependence symptom profiles. Post-hoc across-class comparisons were conducted using a variety of smoking-related variables and aspects of psychopathology. Whether a single class identified offspring at high genetic and environmental vulnerability was also investigated. RESULTS: The cross-diagnosis kappa was .30. A 4-class solution fit these data best. The classes included a low DSM-low FTND class and a high DSM-high FTND class; a moderate DSM-moderate FTND class, which was distinguished by moderate levels of smoking and intermediate levels of comorbid psychopathology; and a light smoking-moderate FTND class consisting primarily of lighter smokers with a more recent onset of regular smoking. High genetic and environmental vulnerability to nicotine dependence was noted in all classes with no statistically significant across-class differences. CONCLUSIONS: In general, the DSM-IV and FTND criteria performed similarly to define a continuum of risk for nicotine dependence. The emerging class of light smokers should be further investigated to assess whether they transition to another class or remain as such.

Exposure to paternal alcoholism does not predict development of alcohol-use disorders in offspring: evidence from an offspring-of-twins study.

OBJECTIVE: Using an offspring-of-twins design, we tested the hypothesis that exposure to paternal alcoholism during the child's first 12 years will increase offspring risk for subsequent alcohol-use disorders (AUD). METHOD: Structured psychiatric interviews assessed history of psychiatric and substance-use disorders in Vietnam Era Twin Registry fathers (n = 512), their offspring (n = 877), and mothers of the offspring (n = 507). Exposure was defined as the fathers' endorsement of any Diagnostic and Statistical Manual of Mental Disorders (DSM), Fourth Edition, AUD symptom, according to the Lifetime Drinking History assessment (administered in 1999), at any time between off- spring ages 0-12 years; all fathers had satisfied DSM, Third Edition, Revised (DSM-III-R), criteria for alcohol dependence in a 1992 diagnostic interview. Cox proportional hazards models were fit to predict time to first symptom of abuse/dependence in offspring. RESULTS: Off- spring exposed to paternal alcoholism were significantly more likely to develop an AUD when compared with offspring of nonalcoholic fathers (hazard ratio [HR] = 1.51; 95% confidence interval [CI]: 1.10-2.07). Although offspring unexposed to paternal alcoholism did not significantly differ from control offspring (HR = 1.50, 95% CI: 0.93-2.41), the magnitude of association was similar to that in the exposed offspring. There were no significant differences in AUD between offspring of alcoholics who were exposed and those who were not exposed to paternal alcoholism, as long as fathers had satisfied DSM-III-R criteria for alcohol dependence at some point in their lives. CONCLUSIONS: There does not appear to be a relationship between exposure to paternal alcoholism during childhood and development of an AUD in offspring. Genetic and high-risk environmental factors that are correlated with lifetime paternal alcoholism may be stronger predictors of offspring AUD than fathers' problem drinking. Future research should be encouraged, using more comprehensive analyses, to examine the role of family genetic influences and other family environmental influences on offspring alcohol outcomes.

Paternal alcoholism and offspring conduct disorder: evidence for the 'common genes' hypothesis.

Not only are alcoholism and externalizing disorders frequently comorbid, they often co-occur in families across generations; for example, paternal alcoholism predicts offspring conduct disorder just as it does offspring alcoholism. To clarify this relationship, the current study examined the 'common genes' hypothesis utilizing a children-of-twins research design. Participants were male monozygotic (MZ) and dizygotic (DZ) twins from the Vietnam Era Twin Registry who were concordant or discordant for alcohol dependence together with their offspring and the mothers of those offspring. All participants were conducted through a structured psychiatric interview. Offspring risk of conduct disorder was examined as a function of alcoholism genetic risk (due to paternal and co-twin alcohol dependence) and alcoholism environmental risk (due to being reared by a father with an alcohol dependence diagnosis). After controlling for potentially confounding variables, the offspring of alcohol-dependent fathers were significantly more likely to exhibit conduct disorder diagnoses than were offspring of nonalcohol-dependent fathers, thus indicating diagnostic crossover in generational family transmission. Comparing offspring at high genetic and high environmental risk with offspring at high genetic and low environmental risk indicated that genetic factors were most likely responsible for the alcoholism-conduct disorder association. The observed diagnostic crossover (from paternal alcoholism to offspring conduct disorder) across generations in the context of both high and low environmental risk (while genetic risk remained high) supported the common genes hypothesis.

Subjective effects to cannabis are associated with use, abuse and dependence after adjusting for genetic and environmental influences.

BACKGROUND: Previous reports in adults have suggested that the effects experienced after cannabis use can be described in terms of positive and negative subtypes that are heritable and are associated with abuse and dependence. This study extends existing research by inclusion of adolescents and young adults in an offspring of twins design which makes it possible to take into account genetic and environmental risks for substance use disorder. METHODS: Data were collected from 725 twin members of the Vietnam Era Twin Registry, 839 of their 12-32 year old biological offspring and 427 mothers. Offspring who had ever used cannabis (n=464) were asked the degree to which they typically experienced 13 subjective effects shortly after using cannabis. Latent class analysis (LCA) was used to derive subjective effect classes and logistic regression models were computed to test associations between subjective effect class and heavy cannabis use, abuse and dependence after adjusting for familial risk and psychopathology and sociodemographics. RESULTS: The best fitting LCA model included 4 classes of responders which were characterized as 'high responders' (39%), 'positive responders' (28%), 'mixed/relaxed' (22%), and 'low responders' (11%). Compared to low responders, members of other classes were heavier users (OR range 3.0-11.8). Compared to mixed/relaxed responders and positive responders, high responders were more likely to have cannabis abuse and dependence. CONCLUSIONS: Subjective reactions to cannabis use are associated with use to heavy use, abuse and dependence in adolescents and young adults. This association exists above and beyond the genetic vulnerability for problem cannabis use.