Alcohol use, smoking habits and the Adult Eysenck Personality Questionnaire in adolescent Australian twins [corrected]

The Relationship Between Personality and Somatic and Psychological Distress: A Comparison of Chinese and Australian Adolescents

The extent to which correlations between personality domains and physical and psychological health generalize cross-culturally is unclear. We compared the strength of associations between the personality domains and somatic and psychological distress in Chinese (N = 2069) and a genetically informative sample of Australian (N = 2936) adolescents. We also examined the genetic and environmental etiology between personality, somatic and psychological distress in an Australian sample of 390 monozygotic twins and 698 dizygotic twins. In both populations, personality was assessed using the Junior Eysenck Personality Questionnaire. Somatic and psychological distress was assessed using the Somatic and Psychological Health Report. We found significant cultural differences in the relationship between adolescents' personality traits and somatic and psychological distress. Extraversion was positively associated with somatic distress in the Chinese but not in Australian adolescents. In the Australian twins, genetic covariation between neuroticism and somatic and psychological distress was stronger compared to the genetic associations between either psychoticism or extraversion with psychological distress.

Extended Twin Study of Alcohol Use in Virginia and Australia

Drinking alcohol is a normal behavior in many societies, and prior studies have demonstrated it has both genetic and environmental sources of variation. Using two very large samples of twins and their first-degree relatives (Australia ≈ 20,000 individuals from 8,019 families; Virginia ≈ 23,000 from 6,042 families), we examine whether there are differences: (1) in the genetic and environmental factors that influence four interrelated drinking behaviors (quantity, frequency, age of initiation, and number of drinks in the last week), (2) between the twin-only design and the extended twin design, and (3) the Australian and Virginia samples. We find that while drinking behaviors are interrelated, there are substantial differences in the genetic and environmental architectures across phenotypes. Specifically, drinking quantity, frequency, and number of drinks in the past week have large broad genetic variance components, and smaller but significant environmental variance components, while age of onset is driven exclusively by environmental factors. Further, the twin-only design and the extended twin design come to similar conclusions regarding broad-sense heritability and environmental transmission, but the extended twin models provide a more nuanced perspective. Finally, we find a high level of similarity between the Australian and Virginian samples, especially for the genetic factors. The observed differences, when present, tend to be at the environmental level. Implications for the extended twin model and future directions are discussed.

Multilevel Risk Models for Retrospective Age-Of-Onset Data

Survival analysis provides a natural conceptual framework for considering risk.However, survey data on age of onset typically possess measurement error and sample design complexities that are absent from the usual settings in which survival analysis is applied.The authors describe a random effects discrete time survival model that addresses these problems.They illustrate its use by an analysis of retrospective report data on the age of onset of smoking from two cross-sectional school-based studies.

Genetic and environmental influences on adolescents' smoking involvement: a multi-informant twin study

Studying monozygotic and dizygotic adolescent twin pairs of both sexes reared together, the present study examined the extent to which the variance in smoking involvement is attributable to genetic and environmental effects, and to what extent there are sex differences in the etiology. Questionnaire data on how often the adolescent had ever smoked tobacco was collected from a population-based twin sample consisting of seven national birth cohorts (ages 12-18), their mothers, and their fathers (N = 1,394 families). The data was analyzed with multivariate genetic modeling, using a multi-informant design. The etiological structure of smoking involvement was best represented in an ACE common pathway model, with smoking defined as a latent factor loading onto all three informants' reports. Estimates could be set equal across sexes. Results showed that adolescent lifetime smoking involvement was moderately heritable (37 %). The largest influence was from the shared environment (56 %), while environmental effects unique to each twin had minimal influence (7 %).

Trends in adolescent alcohol use: effects of age, sex and cohort on prevalence and heritability

AIMS

To determine the effect of age, sex and cohort on the prevalence and genetic architecture of adolescent alcohol use (AAU).

DESIGN

Survey study in participants registered with the Netherlands Twin Register.

SETTING

Twins from the general population.

PARTICIPANTS

Two cohorts (data collected in 1993 and 2005-08) of twins aged 13-15, 16-17 and 18-21 years. In 1993 and 2005-08 a total of 3269 and 8207 twins, respectively, took part.

MEASUREMENTS

Survey data on initiation and frequency of alcohol use and quantity of alcohol consumed.

FINDINGS

The prevalence of alcohol initiation increased between 1993 and 2005-08 for both males and females. The largest difference was for girls observed at ages 13-15, where the prevalence increased from 59.5% to 72.4%. We also found increases in prevalence across cohorts for quantity of alcohol consumed and non-significant increases for frequency of alcohol use. From age 16 onwards, boys drank more frequently and larger quantities than girls. Genetic model fitting revealed that the genetic architecture of AAU did not differ between birth cohorts, nor were there differences between boys and girls. Genetic factors explained between 21% and 55% of individual differences in alcohol measures throughout adolescence. Shared environment explained between 17% and 64% of variance in alcohol use, across different age groups and alcohol measures.

CONCLUSIONS

In the Netherlands, the prevalence of alcohol initiation, frequency and quantity has increased in adolescents over a 15-year period, but there are no changes in the genetic architecture of adolescent alcohol use.

Heritability of smoking, alcohol use, and psychological characteristics among adolescent twins in Qingdao, China

BACKGROUND

Previous studies of genetic and environmental influences on adolescent substance use have been limited to Western samples.

METHODS

This study assesses genetic and environmental contributions to cigarette smoking, alcohol use, and psychological variables (depression, anxiety, aggression, hostility) among 602 pairs of adolescent twins, 11 to 19 years old, in Qingdao, China.

RESULTS

Heritable influences were more pronounced for alcohol use than cigarette smoking. In univariate analyses, no heritable effects were found for depression or aggression, and modest heritability was found for anxiety. Hostility was relatively more heritable in girls than boys. Bivariate associations between substance use and psychological measures could be attributed to a combination of common genetic and environmental factors.

CONCLUSIONS

Among Chinese adolescents, experimentation with tobacco is familial, and experimentation with alcohol is heritable. The genetic and environmental architecture of hostility differs by gender. Consistency of univariate results with Western adolescent samples appears limited to the alcohol use measures.

Does smoking among friends explain apparent genetic effects on current smoking in adolescence and young adulthood?

We used data from a prospective cohort study of twins to investigate the influence of unmeasured genetic and measured and unmeasured environmental factors on the smoking behaviour of adolescents and young adults. Twins were surveyed in 1988 (aged 11-18 years), 1991, 1996 and 2004 with data from 1409, 1121, 732 and 758 pairs analysed from each survey wave, respectively. Questionnaires assessed the smoking behaviour of twins and the perceived smoking behaviour of friends and parents. Using a novel logistic regression analysis, we simultaneously modelled individual risk and excess concordance for current smoking as a function of zygosity, survey wave, parental smoking and peer smoking. Being concordant for having peers who smoked was a predictor of concordance for current smoking (P<0.001). After adjusting for peer smoking, monozygotic (MZ) pairs were no more alike than dizygotic pairs for current smoking at waves 2, 3 and 4. Genetic explanations are not needed to explain the greater concordance for current smoking among adult MZ pairs. However, if they are invoked, the role of genes may be due to indirect effects acting through the social environment. Smoking prevention efforts may benefit more by targeting social factors than attempting to identify genetic factors associated with smoking.

Características psicológicas associadas ao comportamento de fumar tabaco

Este artigo apresenta uma revisão da literatura sobre a psicologia do tabagismo, destacando características de personalidade do fumante como um dos obstáculos à cessação do tabagismo. Descreve-se a relação entre tabagismo e personalidade e, a seguir, a relação do tabagismo com os principais transtornos psiquiátricos. Estudos revelam que os fumantes tendem a ser mais extrovertidos, ansiosos, tensos, impulsivos e com mais traços de neuroticismo e psicoticismo, em comparação a ex-fumantes e não fumantes. A literatura revela, ainda, forte associação entre tabagismo e transtornos mentais, como esquizofrenia e depressão, entre outros. A compreensão dos fatores de natureza psicológica associados ao consumo e à dependência pode contribuir para a elaboração e aperfeiçoamento de estratégias terapêuticas para o tratamento da dependência e/ou programas de cunho educativo/preventivo.

Association between Alcohol Use and Smoking in Adolescent and Young Adult Twins: A Bivariate Genetic Analysis

The association between alcohol use and smoking was examined in a large population-based sample of Dutch twins consisting of three age groups; young adolescent twins aged 12-14 years (n= 650 twin pairs), 15-16-years-old adolescent twins (n= 705 twin pairs), and young adult twins aged 17-25 years (n= 1266 twin pairs). For all three age groups, alcohol use and smoking were correlated (r= 0.5-0.6). Adolescents and young adults who smoked were more likely to drink alcohol than nonsmokers. The relation between alcohol use and smoking was also found within a twin pair; alcohol use in one twin was correlated with smoking in the cotwin. This finding suggested that familial factors contribute to the association between alcohol and tobacco use. With a bivariate genetic model, it was examined to what extent the comorbidity was due to genetic and environmental factors that predispose to both alcohol use and smoking. The genetic analyses showed that the underlying factors that influence alcohol and tobacco use and cause their association were different for adolescent and young adult twins. Initiation of alcohol use and smoking in adolescents (aged 12-16 years) was substantially influenced by the same shared environmental features. Alcohol and tobacco use in young adults were associated due to the same genetic risk factors.

Assessing personality features and their relations with behavioral problems in adolescents: Tridimensional Personality Questionnaire and Junior Eysenck Personality Questionnaire

This study examines the applicability for adolescents of the Tridimensional Personality Questionnaire (TPQ), which was originally designed for adults, as compared to the Junior Eysenck Personality Questionnaire (JEPQ). The study also evaluates their inter-relationship and associations with various behavioral problems as reported by parents using the Child Behavior Checklist (CBCL). In a representative community sample of 905 adolescents, the results of internal consistency, test-retest reliability, and factor analysis showed that both the Harm Avoidance (HA) and the Novelty Seeking (NS) scales of the TPQ have sound construct validity, although the Reward Dependence (RD) scale has less so. The intercorrelation and factor analysis of the two questionnaires showed that the TPQ and the JEPQ are not simply alternative descriptions of the same construct of personality. In their associations with various behavioral problems, the scales of the TPQ are relatively more specifically associated with behavioral problems than the scales of the JEPQ. Our results provide empirical support for the applicability of the NS and the HA scales of the TPQ in adolescents, particularly in relation to behavioral problems.

The role of genes in tobacco smoking during adolescence and young adulthood: a multivariate behaviour genetic investigation

AIMS

To incorporate a psychosocial model of tobacco smoking into a behaviour genetic design to examine genetic and environmental influences on variation in smoking involvement.

DESIGN

Longitudinal twin study.

SETTING AND PARTICIPANTS

Twins initially aged between 13 and 18 years and registered with the Australian Twin Registry were surveyed three times between 1988 and 1996. A total of 414 pairs of identical and same-sex fraternal twin pairs participated in all three surveys, aged between 20 and 25 at wave 3. Biometric modelling estimated the influence of genetic and environmental factors in determining variation in smoking at each wave, both before and after adjusting for perceived smoking behaviours of peers and parents.

MEASUREMENTS

Twins answered a questionnaire on their own smoking status and reported on the use of tobacco by parents and friends as they perceived it, at each survey wave.

FINDINGS

At all three surveys, current smokers were more likely to have parents who smoked and to have smokers among their peers. Genes and environmental factors, both common and unique, contributed to variation in smoking behaviours. However, after controlling for the smoking behaviours of peers and parents, the role of genes in determining variation in smoking involvement was reduced by 100% at wave 1 and by 30% at wave 2. Friends' smoking reduced the magnitude of the common environment variance by 11%, 30% and 40% at waves 1, 2 and 3, respectively. Parents' smoking behaviours explained part of the common environment. Biometric modelling of the covariation between smoking involvement and peer smoking suggested that genes might influence smoking involvement at wave 1 by influencing choice of peers.

CONCLUSION

Environmental factors play the greatest role in determining variation in tobacco smoking among adolescents and young adults. Among adolescents, genes may influence variation in smoking behaviours indirectly by influencing choice of peers. However, genes seem to have a direct influence on variations in the smoking behaviours of young adults.

Review of twin and adoption studies of adolescent substance use

OBJECTIVE

To review studies of adolescent substance use and abuse with genetically informative designs.

METHOD

Twin and adoption studies of adolescent substance use were searched in Medline using keywords.

RESULTS

Of 19 studies that used adolescent samples, 18 examined initiation or use of substances and 1 examined abuse. Of the 7 retrospective studies using adult samples, 6 examined problematic behaviors such as substance dependence. Genetic and shared environmental influences on adolescent substance use are moderated by the specific substance, age, gender, specific contexts, religiousness, and region. There is some evidence for a common genetic influence on substance use across substances. Genetic influences on adolescent substance use may act through an influence on disinhibited behavior. Shared environment contributed to adolescent substance use consistently across all adolescent samples and common shared environmental influences influenced initiation into tobacco and alcohol use. While parental alcohol use had a small influence on adolescent shared environment, sibling influences were substantial.

CONCLUSIONS

Twin and adoption studies have increased our understanding of genetic and environmental influences on adolescent substance use and its initiation; however, more studies focusing on clinical syndromes of abuse and dependence are needed.

Substance use among adolescents in Taiwan: associated personality traits, incompetence, and behavioral/emotional problems

BACKGROUND

Despite that adolescent substance use is increasingly prevalent throughout the world and leads to increased risk of progression to illicit drug use, few studies have examined in detail individual features that are associated with such use. We aimed to examine personality traits, incompetence, and behavioral/emotional problems in relation to adolescent substance use and possible interactions between these factors.

METHODS

Junior high school adolescents (N = 905) randomly selected from Taipei in 1996 completed a questionnaire consisting of substance use experience, the Junior Eysenck Personality Questionnaire (JEPQ), and the Tridimensional Personality Questionnaire (TPQ). Students' parents (N = 854) were asked to complete the Child Behavior Checklist. Logistic regression was used to assess the relationship between substance use and personality traits or behavioral problems.

RESULTS

The most commonly used substance was liquid substance (alcohol and refreshing beverage), followed by tobacco and betel nut with an age-related trend in boys. Associated factors of substance use included higher Extroversion and lower Lie Scale (as measured in the JEPQ), higher Novelty Seeking (as measured in the TPQ), poorer School Competence, and more Delinquent Behavior, Aggressive Behavior, and Somatic Complaints. The associations remained unchanged with potential confounders controlled for.

CONCLUSIONS

Adolescents who use substance have specific individual features that are readily assessable by existing instruments. This bears important implications for the early intervention of substance abuse in adolescents.

Eysenck's personality and tobacco/nicotine dependence in male ever-smokers in Japan

To examine the relationship between Eysenck's personality traits and tobacco/nicotine dependence in a male population, a random sample of 200 male ever-smokers aged 35 or older from a community in Japan were interviewed using the World Health Organization (WHO) Composite International Diagnostic Interview (CIDI), which yielded ICD-10, DSM-III-R and DSM-IV diagnoses of tobacco/nicotine dependence. They were also asked to complete the Fagerstrom Tobacco Questionnaire (FTQ) and the short-form Eysenck Personality Questionnaire-Revised. A total of 136 subjects completed both the interview and the questionnaire. Neuroticism scores were significantly higher in those who had lifetime diagnosis of tobacco/nicotine dependence according to ICD-10, DSM-IV, or FTQ criteria than nondependent ever-smokers (p < 0.05). Lie scores were significantly lower in DSM-III-R or DSM-IV tobacco/nicotine dependence than in nondependent ever-smokers (p < 0.05). Multiple logistic regression indicated that neuroticism was significantly associated with a higher risk of ICD-10 tobacco/nicotine dependence (p < 0.05), after controlling for age, education, employment status and smoking behaviors; lie score was significantly associated with a lower risk of DSM-III-R tobacco/nicotine dependence (p < 0.05). It is suggested that neuroticism is associated with a higher risk of tobacco/nicotine dependence in male Japanese ever-smokers. A nonconforming and rebellious attitude or reporting bias represented by higher lie score may be associated with lower rates of tobacco/nicotine dependence.

Regressive logistic modeling of familial aggregation for asthma in 7,394 population-based nuclear families

The aim of this population-based study was to determine whether asthma aggregates in families, and if so, whether aggregation was consistent with environmental and/or genetic etiologies. Data were from 7,394 nuclear families (41,506 individuals) from the 1968 Tasmanian Asthma Survey, in which all Tasmanian schoolchildren born in 1961 were surveyed by respiratory questionnaire completed by their parents. Similar data were obtained for parents and siblings of probands. For a child, having ever had asthma was predicted by a parent or sibling having ever had asthma; odds ratio (OR) = 3.13 (95% confidence interval [CI] 2.82-3.48) for mother, 2.99 (2.69-3.32) for father, and 3.47 (3.23-3.72) for a sibling. Regressive logistic modeling showed that, in addition to parent-offspring effects, the data were consistent with the existence of an unmeasured factor shared by siblings, evident in 15% (SE 2%) of families and associated with a conditional OR of 9.68 (8.27-11.32). Familial aggregation was best described by a general oligogenic model with non-Mendelian transmission probabilities. Of the Mendelian models, a codominant model with an allele frequency of 16% (SE 0.3%) was preferred. Under a dominant model there was evidence for additional parent-offspring and sibling effects of similar magnitude. It is unlikely that there is one major loci influencing asthma susceptibility; the overall effects of asthma genes in the population are more likely to be inherited codominantly, at least for the majority of loci of major etiological importance. The role of environmental factors in explaining part of familial aggregation for asthma cannot be ruled out, as major triggers of asthma attacks are familial.

Relation between the longitudinal development of personality characteristics and biological and lifestyle risk factors for coronary heart disease

OBJECTIVE

This study was undertaken to assess the stability of personality characteristics (ie, inadequacy, rigidity, dominance, self-sufficiency, and social inadequacy) over a 15-year period covering adolescence and young adulthood and to analyze the longitudinal relationships between personality characteristics and both biological (ie, lipoproteins, blood pressure, and body fatness) and lifestyle (ie, physical activity, dietary intake, smoking, and alcohol consumption) risk factors for coronary heart disease (CHD).

METHODS

The data were derived from the Amsterdam Growth and Health Study, an observational longitudinal study in which, over a period from 13 to 27 years of age, six repeated measurements were performed on 181 subjects. Both the stability analysis and the analysis of the longitudinal relationships were performed by generalized estimating equations (GEE). This method is suitable for both continuous and dichotomous outcome variables, by using all available longitudinal data.

RESULTS

Stability coefficients for the personality characteristics varied between 0.39 for self-sufficiency and dominance and 0.53 for social inadequacy. Self-sufficiency was inversely related to total serum cholesterol (only male subjects) and body fatness; inadequacy was inversely related to systolic blood pressure. Dominance (female subjects) was positively related to body fatness and social inadequacy (male subjects) was positively related to total serum cholesterol. Furthermore, inadequacy was positively related to smoking behavior. Social inadequacy and rigidity were inversely related to smoking behavior. Self-sufficiency was inversely related to alcohol consumption.

CONCLUSIONS

Over a period of 15 years, personality characteristics showed marginal stability. Weak relationships were found between personality characteristics and both biological and lifestyle CHD risk factors.

Genetic and environmental variation in Eysenck Personality Questionnaire scales measured on Australian adolescent twins

The Eysenck Personality Questionnaire was administered to 1400 Australian twin pairs aged 11 to 18, and the data were analyzed by a multivariate normal model using the software FISHER. For each scale, attempts were made to transform to normality, about a mean modeled separately for each sex as a quadratic function of age. Variances and covariances were estimated for each sex-zygosity group as a monotone function of age. Evidence for genetic sources of variation were assessed in part by fitting models which allowed for age-dependent, sex-specific, and correlated additive genetic factors, and age-dependent and sex-specific environmental factors, under the assumption that effects of environmental factors common to twin pairs are independent of zygosity. Evidence for genetic factors independent of age and sex was most compelling for Psychoticism and Neuroticism. For Extraversion, if genetic factors exist they would be mostly sex-specific and age-dependent. For the Lie scale there was evidence for, at most, a small component of genetic variation.