RESUMO
BACKGROUND: Mental health disorders commonly co-occur, even between conceptually distinct syndromes, such as internalizing and externalizing disorders. The current study investigated whether phenotypic, genetic, and environmental variance in negative emotionality and behavioral control account for the covariation between major depressive disorder (MDD) and alcohol use disorder (AUD). METHOD: A total of 3623 members of a national twin registry were administered structured diagnostic telephone interviews that included assessments of lifetime histories of MDD and AUD, and were mailed self-report personality questionnaires that assessed stress reactivity (SR) and behavioral control (CON). A series of biometric models were fitted to partition the proportion of covariance between MDD and AUD into SR and CON. RESULTS: A statistically significant proportion of the correlation between MDD and AUD was due to variance specific to SR (men = 0.31, women = 0.27) and CON (men = 0.20, women = 0.19). Further, genetic factors explained a large proportion of this correlation (0.63), with unique environmental factors explaining the rest. SR explained a significant proportion of the genetic (0.33) and environmental (0.23) overlap between MDD and AUD. In contrast, variance specific to CON accounted for genetic overlap (0.32), but not environmental overlap (0.004). In total, SR and CON accounted for approximately 70% of the genetic and 20% of the environmental covariation between MDD and AUD. CONCLUSIONS: This is the first study to demonstrate that negative emotionality and behavioral control confer risk for the co-occurrence of MDD and AUD via genetic factors. These findings are consistent with the aims of NIMH's RDoC proposal to elucidate how transdiagnostic risk factors drive psychopathology.
Assuntos
Transtornos Relacionados ao Uso de Álcool , Transtorno Depressivo Maior , Emoções/fisiologia , Personalidade/fisiologia , Sistema de Registros , Autocontrole , Adulto , Transtornos Relacionados ao Uso de Álcool/epidemiologia , Transtornos Relacionados ao Uso de Álcool/etiologia , Transtornos Relacionados ao Uso de Álcool/genética , Transtornos Relacionados ao Uso de Álcool/fisiopatologia , Austrália/epidemiologia , Comorbidade , Transtorno Depressivo Maior/epidemiologia , Transtorno Depressivo Maior/etiologia , Transtorno Depressivo Maior/genética , Transtorno Depressivo Maior/fisiopatologia , Feminino , Humanos , MasculinoRESUMO
BACKGROUND: Childhood maltreatment (CM) has consistently been linked with adverse outcomes including substance use disorders and adult sexual revictimization. Adult sexual victimization itself has been linked with psychopathology but has predominately been studied in women. The current investigation examines the impact of CM and co-occurring psychopathology on adult sexual victimization in men and women, replicating findings in three distinct samples. METHOD: We investigated the association between continuous CM factor scores and adult sexual victimization in the Childhood Trauma Study (CTS) sample (N = 2564). We also examined the unique relationship between childhood sexual abuse (CSA) and adult sexual victimization while adjusting for co-occurring substance dependence and psychopathology. We replicated these analyses in two additional samples: the Comorbidity and Trauma Study (CATS; N = 1981) and the Australian Twin-Family Study of Alcohol Use Disorders (OZ-ALC; N = 1537). RESULTS: Analyses revealed a significant association with CM factor scores and adult sexual victimization for both men and women across all three samples. The CSA factor score was strongly associated with adult sexual victimization after adjusting for substance dependence and psychopathology; higher odds ratios were observed in men (than women) consistently across the three samples. CONCLUSIONS: A continuous measure of CSA is independently associated with adult sexual trauma risk across samples in models that included commonly associated substance dependence and psychopathology as covariates. The strength of the association between this CSA measure and adult sexual victimization is higher in magnitude for men than women, pointing to the need for further investigation of sexual victimization in male community samples.
Assuntos
Sobreviventes Adultos de Maus-Tratos Infantis/psicologia , Sobreviventes Adultos de Maus-Tratos Infantis/estatística & dados numéricos , Abuso Sexual na Infância/psicologia , Delitos Sexuais/psicologia , Adulto , Austrália , Criança , Comorbidade , Feminino , Humanos , Modelos Logísticos , Masculino , Pessoa de Meia-Idade , Análise Multivariada , Fatores Sexuais , Fatores Socioeconômicos , Transtornos Relacionados ao Uso de Substâncias/epidemiologiaRESUMO
BACKGROUND: Genetic influences contribute significantly to co-morbidity between conduct disorder and substance use disorders. Estimating the extent of overlap can assist in the development of phenotypes for genomic analyses. METHOD: Multivariate quantitative genetic analyses were conducted using data from 9577 individuals, including 3982 complete twin pairs and 1613 individuals whose co-twin was not interviewed (aged 24-37 years) from two Australian twin samples. Analyses examined the genetic correlation between alcohol dependence, nicotine dependence and cannabis abuse/dependence and the extent to which the correlations were attributable to genetic influences shared with conduct disorder. RESULTS: Additive genetic (a(2) = 0.48-0.65) and non-shared environmental factors explained variance in substance use disorders. Familial effects on conduct disorder were due to additive genetic (a(2) = 0.39) and shared environmental (c(2) = 0.15) factors. All substance use disorders were influenced by shared genetic factors (rg = 0.38-0.56), with all genetic overlap between substances attributable to genetic influences shared with conduct disorder. Genes influencing individual substance use disorders were also significant, explaining 40-73% of the genetic variance per substance. CONCLUSIONS: Among substance users in this sample, the well-documented clinical co-morbidity between conduct disorder and substance use disorders is primarily attributable to shared genetic liability. Interventions targeted at generally reducing deviant behaviors may address the risk posed by this shared genetic liability. However, there is also evidence for genetic and environmental influences specific to each substance. The identification of these substance-specific risk factors (as well as potential protective factors) is critical to the future development of targeted treatment protocols.
Assuntos
Transtorno da Conduta/genética , Doenças em Gêmeos/genética , Interação Gene-Ambiente , Transtornos Relacionados ao Uso de Substâncias/genética , Gêmeos/genética , Adolescente , Adulto , Austrália , Cannabis , Criança , Comorbidade , Etanol , Feminino , Humanos , Masculino , Análise Multivariada , Nicotina , Fenótipo , Sistema de Registros , Fatores de Risco , Adulto JovemRESUMO
Major depressive disorder (MDD) is a common complex disorder with a partly genetic etiology. We conducted a genome-wide association study of the MDD2000+ sample (2431 cases, 3673 screened controls and >1 M imputed single-nucleotide polymorphisms (SNPs)). No SNPs achieved genome-wide significance either in the MDD2000+ study, or in meta-analysis with two other studies totaling 5763 cases and 6901 controls. These results imply that common variants of intermediate or large effect do not have main effects in the genetic architecture of MDD. Suggestive but notable results were (a) gene-based tests suggesting roles for adenylate cyclase 3 (ADCY3, 2p23.3) and galanin (GAL, 11q13.3); published functional evidence relates both of these to MDD and serotonergic signaling; (b) support for the bipolar disorder risk variant SNP rs1006737 in CACNA1C (P=0.020, odds ratio=1.10); and (c) lack of support for rs2251219, a SNP identified in a meta-analysis of affective disorder studies (P=0.51). We estimate that sample sizes 1.8- to 2.4-fold greater are needed for association studies of MDD compared with those for schizophrenia to detect variants that explain the same proportion of total variance in liability. Larger study cohorts characterized for genetic and environmental risk factors accumulated prospectively are likely to be needed to dissect more fully the etiology of MDD.
Assuntos
Adenilil Ciclases/genética , Canais de Cálcio Tipo L/genética , Transtorno Depressivo Maior/genética , Galanina/genética , Predisposição Genética para Doença/genética , Polimorfismo de Nucleotídeo Único/genética , Adolescente , Adulto , Feminino , Estudo de Associação Genômica Ampla , Genótipo , Humanos , Masculino , Pessoa de Meia-Idade , Razão de Chances , Análise de Componente Principal , Fatores Sexuais , Adulto JovemRESUMO
BACKGROUND: Associations between parental depression and offspring affective and disruptive disorders are well documented. Few genetically informed studies have explored the processes underlying intergenerational associations. METHOD: A semi-structured interview assessing DSM-III-R psychiatric disorders was administered to twins (n=1296) from the Australian Twin Register (ATR), their spouses (n=1046) and offspring (n=2555). We used the Children of Twins (CoT) design to delineate the extent to which intergenerational associations were consistent with a causal influence or due to genetic confounds. RESULTS: In between-family analyses, parental depression was associated significantly with offspring depression [hazard ratio (HR) 1.52, 95% confidence interval (CI) 1.20-1.93] and conduct disorder (CD; HR 2.27, CI 1.31-3.93). Survival analysis indicated that the intergenerational transmission of depression is consistent with a causal (environmental) inference, with a significant intergenerational association in offspring of discordant monozygotic (MZ) twin pairs (HR 1.39, CI 1.00-1.94). Logistic regression analysis suggested that the parental depression-offspring CD association was due to shared genetic liability in the parents and offspring. No intergenerational association was found when comparing the offspring of discordant MZ twins [odds ratio (OR) 1.41, CI 0.63-3.14], but offspring of discordant dizygotic (DZ) twins differed in their rates of CD (OR 2.53, CI 0.95-6.76). All findings remained after controlling for several measured covariates, including history of depression and CD in the twins' spouses. CONCLUSIONS: The mechanisms underlying associations between parental depression and offspring psychopathology seem to differ depending on the outcome. The results are consistent with a causal environmental role of parental depression in offspring depression whereas common genetic factors account for the association of parental depression and offspring CD.
Assuntos
Filho de Pais com Deficiência/psicologia , Transtorno da Conduta/epidemiologia , Transtorno da Conduta/psicologia , Transtorno Depressivo Maior/epidemiologia , Transtorno Depressivo Maior/psicologia , Pais/psicologia , Adolescente , Adulto , Austrália/epidemiologia , Filho de Pais com Deficiência/estatística & dados numéricos , Transtorno da Conduta/genética , Transtorno Depressivo Maior/genética , Feminino , Predisposição Genética para Doença/genética , Predisposição Genética para Doença/psicologia , Humanos , Relação entre Gerações , Entrevista Psicológica , Masculino , Razão de Chances , Prevalência , Cônjuges/psicologia , Cônjuges/estatística & dados numéricos , Análise de Sobrevida , Gêmeos/psicologia , Gêmeos Monozigóticos/genética , Gêmeos Monozigóticos/psicologia , Adulto JovemRESUMO
BACKGROUND: Depression affects more women than men and often aggregates in families. Using a community-based sample of twins, we examined the contributions of genetic and environmental factors to the risk of developing major depressive disorder and the effect of sex and different definitions of depression on the relative contributions of genetic and environmental effects. Sex differences in genetic effects were also studied. METHODS: A volunteer sample of Australian twins (2662 pairs) was interviewed using an abbreviated version of the Semi-Structured Assessment for the Genetics of Alcoholism, a semi-structured lay interview designed to assess psychiatric disorders. Depression was defined using 3 different criteria sets: DSM-III-R major depressive disorder, DSM-IV major depressive disorder, and severe DSM-IV major depressive disorder. Genetic and environmental contributions to the liability to develop depression were estimated using genetic model fitting. RESULTS: Lifetime prevalences were 31% in women and 24% in men for DSM-III-R major depressive disorder, 22% in women and 16% in men for DSM-IV major depressive disorder, and 9% in women and 3% in men for severe DSM-IV major depressive disorder. In women, the simplest model to fit the data implicated genetic factors and environmental factors unique to the individual in the development of depression, with heritability estimates ranging from 36% to 44%. In men, depression was only modestly familial, and thus individual environmental factors played a larger role in the development of depression. For DSM-III-R major depressive disorder, there were statistically different estimates for heritability for men vs. women. For both sexes, the relative contributions of genetic and environmental factors were stable using different definitions of depression. CONCLUSIONS: There was moderate familial aggregation of depression in women and this primarily was attributable to genetic factors. In men, there was only modest familial aggregation of depression. For both men and women, individual environmental experiences played a large role in the development of depression. Major depressive disorder as defined by DSM-III-R was more heritable in women as compared with men. The relative contributions of genetic and environmental factors in the development of depression were similar for varying definitions of depression, from a broad definition to a narrow definition.
Assuntos
Transtorno Depressivo/epidemiologia , Doenças em Gêmeos/epidemiologia , Adulto , Fatores Etários , Idoso , Idoso de 80 Anos ou mais , Austrália/epidemiologia , Transtorno Depressivo/diagnóstico , Transtorno Depressivo/genética , Doenças em Gêmeos/diagnóstico , Doenças em Gêmeos/genética , Família , Feminino , Predisposição Genética para Doença , Humanos , Masculino , Pessoa de Meia-Idade , Modelos Genéticos , Prevalência , Escalas de Graduação Psiquiátrica/estatística & dados numéricos , Fatores de Risco , Fatores Sexuais , Meio Social , Terminologia como Assunto , Gêmeos Dizigóticos/genética , Gêmeos Monozigóticos/genéticaRESUMO
BACKGROUND: In the present study, we examined the relationship between cannabis involvement and suicidal ideation (SI), plan and attempt, differentiating the latter into planned and unplanned attempt, taking into account other substance involvement and psychopathology. METHODS: We used two community-based twin samples from the Australian Twin Registry, including 9583 individuals (58.5% female, aged between 27 and 40). The Semi-Structured Assessment of the Genetics of Alcoholism (SSAGA) was used to assess cannabis involvement which was categorized into: (0) no cannabis use (reference category); (1) cannabis use only; (2) 1-2 cannabis use disorder symptoms; (3) 3 or more symptoms. Separate multinomial logistic regression analyses were conducted for SI and suicide attempt with or without a plan. Twin analyses examined the genetic overlap between cannabis involvement and SI. RESULTS: All levels of cannabis involvement were related to SI, regardless of duration (odds ratios [ORs]=1.28-2.00, p<0.01). Cannabis use and endorsing ≥3 symptoms were associated with unplanned (SANP; ORs=1.95 and 2.51 respectively, p<0.05), but not planned suicide attempts (p>0.10). Associations persisted even after controlling for other psychiatric disorders and substance involvement. Overlapping genetic (rG=0.45) and environmental (rE=0.21) factors were responsible for the covariance between cannabis involvement and SI. CONCLUSIONS: Cannabis involvement is associated, albeit modestly, with SI and unplanned suicide attempts. Such attempts are difficult to prevent and their association with cannabis use and cannabis use disorder symptoms requires further study, including in different samples and with additional attention to confounders.
Assuntos
Abuso de Maconha/psicologia , Fumar Maconha/psicologia , Ideação Suicida , Tentativa de Suicídio/psicologia , Suicídio/psicologia , Adulto , Austrália , Feminino , Humanos , Masculino , Gêmeos/psicologia , Prevenção do SuicídioRESUMO
BACKGROUND: Few studies of sexual attitudes and behaviour have quantified the direction and magnitude of participation bias, primarily because information on non-responders is difficult to obtain in cross-sectional surveys. METHOD: Australian adult twins (n = 9112) aged 17-52 years enrolled in a national, longitudinal research register were asked to participate in a postal survey concerning their sexual behaviour and attitudes. Individual consent was determined by separate return of a consent form; 27% explicitly refused, 19% initially agreed to receive a questionnaire, but subsequently did not return consent forms and 52% explicitly consented. Participation data were matched to social, psychological and behavioural information in a longitudinal data set. RESULTS: People who explicitly consented had higher levels of education, attended church less often, had less conservative sexual attitudes and voting preferences, were more likely to smoke cigarettes and drank alcohol more often than people who explicitly refused. On standard personality scales, responders were more novelty-seeking and reward-dependent and less harm-avoidant than refusers. Structured psychiatric telephone interview data from 3674 individuals showed that, compared to refusers, responders had higher lifetime prevalence of major depression, alcohol dependence and childhood conduct disorder and also reported an earlier age at first sexual intercourse and higher rates of sexual abuse. In general, those who had initially agreed to receive the sex questionnaire but were subsequently lost were more similar to consenters than to refusers. CONCLUSIONS: Effect sizes on most measures were small. The broad profile suggests that postal surveys of sexual attitudes and behaviour may overestimate sexual liberalism, activity and adversity, although this bias should not seriously compromise population estimates.
Assuntos
Viés , Comportamento Sexual/psicologia , Adolescente , Adulto , Atitude , Austrália/epidemiologia , Coleta de Dados , Demografia , Feminino , Humanos , Masculino , Saúde Mental , Pessoa de Meia-Idade , Personalidade , Comportamento Sexual/estatística & dados numéricosRESUMO
Associations between self-report symptom profiles for nicotine withdrawal, personality (TPQ, EPQ-R), life-time history of psychopathology and smoking history were examined in data obtained from 553 female adult Australian twins (246 regular smokers), aged 32-48 years, who had participated in a telephone interview survey that included life-time assessments of smoking history, nicotine dependence and symptoms of withdrawal. Two hundred and two respondents were from high-risk pairs where either the respondent or the respondent's co-twin had reported a life-time history of alcohol dependence; 351 were from control pairs. Latent class analysis was used to identify subtypes ('classes') of smokers reporting similar withdrawal symptom profiles. Three major classes were identified which appeared to represent a continuum from mild to severe nicotine withdrawal. Smokers from the severe withdrawal class were best characterized by hands shaking and by the prominence of depressive features. There were marked increases in life-time alcohol dependence rates as a function of severity class. In contrast, significantly elevated rates of major depression, conduct disorder and anxiety disorder were observed only among smokers from the most severe withdrawal class. Neuroticism was the only personality factor strongly associated with the development of withdrawal symptoms.
Assuntos
Doenças em Gêmeos , Nicotina/efeitos adversos , Síndrome de Abstinência a Substâncias/psicologia , Adulto , Feminino , Humanos , Transtornos Mentais/induzido quimicamente , Pessoa de Meia-Idade , Personalidade , Fumar , Tabagismo/complicaçõesRESUMO
The etiology of conduct disorder (CD) was examined retrospectively in a sample of 2,682 male, female, and unlike-sex adult twin pairs from the community-based Australian Twin Register. Model-fitting analyses indicated a substantial genetic influence on risk for CD, accounting for 71% of the variance (95% confidence interval [CI] = 32-79%). There was not a statistically significant effect of the shared environment in the best-fitting model of CD, but a modest effect of the shared environment on the risk for CD could not be rejected (95% CI = 0-32%). The magnitude of genetic and environmental influences for CD liability did not vary significantly for boys and girls, and the specific genetic and environmental mechanisms important for the development of CD appeared to be largely the same for both sexes. The fit of a multiple-threshold model raises the possibility that CD may not necessarily be a discrete entity but rather an extreme of the normal variation in conduct-disordered behavior found in the general population.
Assuntos
Transtornos do Comportamento Infantil/genética , Doenças em Gêmeos/genética , Modelos Genéticos , Meio Social , Adulto , Idoso , Idoso de 80 Anos ou mais , Transtorno da Personalidade Antissocial/genética , Transtorno da Personalidade Antissocial/psicologia , Criança , Transtornos do Comportamento Infantil/psicologia , Doenças em Gêmeos/psicologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Fatores SexuaisRESUMO
The association between retrospectively reported childhood conduct disorder (CD) and a history of alcohol dependence (AD) was examined in a sample of 2,682 male, female, and unlike-sex adult twin pairs. There was a strong association between CD and AD in both men (tetrachoric r = .34, odds ratio = 2.8) and women (tetrachoric r = .53, odds ratio = 9.9). Genetic factors accounted for most of the association between CD and AD liability in men and women, with the remainder of the association being due to nonshared individual-specific environmental factors. Genetic influences common to CD and AD accounted for 17% and 35% of the genetic variation in AD liability in men and women, respectively, and accounted for 11% and 23% of the total variation in AD liability in men and women, respectively. The results suggest that there are common genetic risk factors for CD and AD or that CD itself is an important genetically influenced risk factor for AD.
Assuntos
Transtornos Relacionados ao Uso de Álcool/genética , Transtorno da Conduta/genética , Gêmeos Dizigóticos/estatística & dados numéricos , Gêmeos Monozigóticos/estatística & dados numéricos , Adulto , Idoso , Idoso de 80 Anos ou mais , Transtornos Relacionados ao Uso de Álcool/epidemiologia , Austrália/epidemiologia , Distribuição de Qui-Quadrado , Comorbidade , Transtorno da Conduta/epidemiologia , Feminino , Humanos , Análise dos Mínimos Quadrados , Funções Verossimilhança , Masculino , Pessoa de Meia-Idade , Modelos Genéticos , Razão de Chances , Estudos Retrospectivos , Fatores de RiscoRESUMO
OBJECTIVE: Previous research suggests that family history of alcoholism assessments may be biased by characteristics of the informant. In this report, the reliability and potential biases in offspring reports of paternal and maternal alcohol-related problems were examined in a large community sample of adult twins. METHOD: Subjects were volunteer participants in the Australian NH&MRC twin registry. Agreement between twin pairs on reports of paternal and maternal alcohol problems was assessed in 2,657 twin pairs (1,444 female-female pairs, 626 male-male pairs, and 587 female-male pairs). In addition, to detect systematic reporting biases, like-sex twin pairs whose paternal alcohol problems reports disagreed (n = 164) were contrasted on measures of personality, state anxiety and depression, parental rearing, alcoholism, and alcohol use. RESULTS: Twin agreement for parental alcohol-related problems was good, with overall kappas of .66 for paternal and .58 for maternal alcohol problems. When discordant twin pairs were compared, we found that women who reported that their father had alcohol problems were significantly lower on EPQ-R Social Conformity than their twin sister who denied paternal alcohol problems: and there was a trend for men who reported that their father had alcohol problems to be higher in negative perceived parenting from father than their twin brother who denied paternal alcohol problems. Twins discordant for reporting paternal alcohol problems did not, however, differ on the major dimensions of personality, state anxiety and depression, alcoholism, or current alcohol use. CONCLUSIONS: The results of this study bolster our confidence in using the family history method to examine characteristics of offspring of alcoholics versus offspring of nonalcoholics on self-reported measures of personality and psychopathology, but suggest that some caution should be exercised when using this method to examine differences in offspring-reported perceptions of parental rearing practices.
Assuntos
Alcoolismo/genética , Atitude Frente a Saúde , Filho de Pais com Deficiência/psicologia , Doenças em Gêmeos/genética , Individualidade , Adulto , Idoso , Idoso de 80 Anos ou mais , Alcoolismo/psicologia , Doenças em Gêmeos/psicologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Determinação da Personalidade/estatística & dados numéricos , Psicometria , Reprodutibilidade dos TestesRESUMO
Stuttering is a developmental disorder of speech production that usually emerges in childhood. In this study, a large population-based twin sample from the Australian Twin Registry (1567 pairs and 634 singles aged 17-29 years) was screened to identify twin pairs in which one or both members reported themselves to be affected by stuttering. Telephone interview-based diagnoses were obtained for 457 of these individuals (self-reported affected cases, cotwins, and controls) to determine whether the self-report was correct. To correct for ascertainment bias we carried out a bivariate analysis of the final diagnosis in the selected sample with the screening item in the full sample, using the categorical raw data option of Mx 1.47c. After correcting for ascertainment bias, approximately 70% (95% confidence interval: 39-86%) of the variance in liability to stuttering was found to be attributable to additive genetic effects, with the remainder due to nonshared environmental effects.
Assuntos
Doenças em Gêmeos/genética , Meio Social , Gagueira/genética , Adolescente , Adulto , Estudos de Coortes , Feminino , Predisposição Genética para Doença/genética , Humanos , Masculino , Fatores de Risco , Gagueira/psicologia , Gêmeos Dizigóticos/genética , Gêmeos Monozigóticos/genéticaRESUMO
It is widely believed that people can remember the age at which they first had sexual intercourse. Questions about age at onset are routinely asked in population sexual behaviour surveys and in clinical history-taking. However, there are limited test-retest data, especially with regard to individual differences in unreliable recall. In this study, telephone interviews and follow-ups an average of 15 months later were conducted with 570 non-virgin subjects aged between 28 and 73 years. Test-retest correlations for recalled age at first intercourse were 0.85 for females and 0.91 for males. Consistency was slightly lower among older people and women with a history of sexual abuse. There were no significant associations between consistency of recall and measures of personality, educational background or history of alcohol dependence and depression.
Assuntos
Coito/psicologia , Rememoração Mental , Inquéritos e Questionários/normas , Adulto , Fatores Etários , Idoso , Criança , Abuso Sexual na Infância/psicologia , Feminino , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Personalidade , Reprodutibilidade dos TestesRESUMO
Multivariate modelling of anxiety and depression data in twins has suggested that the two phenotypes are largely underpinned by one genetic factor, while other studies have indicated a relationship between these disorders and the neuroticism personality trait. As part of a study to identify quantitative trait loci for anxiety and depression, questionnaire responses and interviews of 15,027 Australian twins and 11,389 of their family members conducted during the past 20 years were reviewed to identify individuals with neuroticism, anxiety and depression scores in the upper or lower deciles of the population. This information was then used to identify extreme discordant and concordant (EDAC) sib pairs. 1373 high-scoring and 1571 low-scoring subjects (2357 sib pairs) were selected for participation, and extremely high participation rates were achieved, with over 90% of contactable prospective participants completing the interview phase, and over 90% of these providing blood or buccal samples. Participation bias arising from the nature of the selection variables was minimal, with only a small difference between rates of interview participation among prospective participants with high and low selection scores (89.4% vs 91.6%). The interview permitted the diagnosis of depression and several anxiety disorders (OCD, agoraphobia, panic disorder, generalised anxiety disorder) in this sample according to DSM-IV criteria. The methodology for selection of prospective subjects was demonstrated to be extremely successful, with highly significant differences in depression and anxiety disorder prevalence rates between individuals in the two selection groups. The success of this EDAC sampling scheme will enhance the power for QTL linkage and association analysis in this sample.
Assuntos
Ansiedade/genética , Depressão/genética , Ligação Genética/genética , Transtornos Neuróticos/genética , Gêmeos/genética , Adulto , Ansiedade/complicações , Ansiedade/diagnóstico , Ansiedade/psicologia , Austrália , Depressão/complicações , Depressão/diagnóstico , Depressão/psicologia , Feminino , Seguimentos , Genótipo , Humanos , Entrevista Psicológica , Estilo de Vida , Masculino , Pessoa de Meia-Idade , Modelos Genéticos , Análise Multivariada , Transtornos Neuróticos/complicações , Transtornos Neuróticos/diagnóstico , Transtornos Neuróticos/psicologia , Seleção de Pacientes , Fenótipo , Escalas de Graduação Psiquiátrica , Sistema de Registros , Índice de Gravidade de Doença , Inquéritos e Questionários , Gêmeos/psicologiaRESUMO
BACKGROUND: This paper examines genetic and environmental contributions to risk of cannabis dependence. METHOD: Symptoms of cannabis dependence and measures of social, family and individual risk factors were assessed in a sample of 6265 young adult male and female Australian twins born 1964-1971. RESULTS: Symptoms of cannabis dependence were common: 11.0% of sample (15.1% of men and 7.8% of women) reported two or more symptoms of dependence. Correlates of cannabis dependence included educational attainment, exposure to parental conflict, sexual abuse, major depression, social anxiety and childhood conduct disorder. However, even after control for the effects of these factors, there was evidence of significant genetic effects on risk of cannabis dependence. Standard genetic modelling indicated that 44.7% (95% CI = 15-72.2) of the variance in liability to cannabis dependence could be accounted for by genetic factors, 20.1% (95% CI = 0-43.6) could be attributed to shared environment factors and 35.3% (95% CI = 26.4-45.7) could be attributed to non-shared environmental factors. However, while there was no evidence of significant gender differences in the magnitude of genetic and environmental influences, a model which assumed both genetic and shared environmental influences on risks of cannabis dependence among men and shared environmental but no genetic influences among women provided an equally good fit to the data. CONCLUSIONS: There was consistent evidence that genetic risk factors are important determinants of risk of cannabis dependence among men. However, it remains uncertain whether there are genetic influences on liability to cannabis dependence among women.
Assuntos
Doenças em Gêmeos , Abuso de Maconha/genética , Meio Social , Adulto , Austrália , Feminino , Predisposição Genética para Doença/genética , Humanos , Masculino , Abuso de Maconha/psicologia , Risco , Fatores SexuaisRESUMO
BACKGROUND: Many reports have appeared on associations between platelet monoamine oxidase (MAO) activity and susceptibility to psychiatric conditions; principally alcohol dependence but also conduct disorder, other drug use and depression. Recently, it has become apparent that MAO activity is inhibited by some component of cigarette smoke, and smokers have low platelet MAO activity. Since the prevalence of smoking is higher in many of the conditions in which MAO has been implicated, the MAO susceptibility associations may be partly, or entirely, false. METHODS: We have measured platelet MAO in 1551 subjects, recruited from the Australian NHMRC Twin Registry, who have provided information on alcohol use and dependence, smoking, conduct disorder, depression, attempted suicide, panic disorder and social phobia. RESULTS: Current smoking reduced platelet MAO activity in a significant and dose-related manner, with no evidence of lower MAO in ex-smokers or in non-smoking subjects with co-twins who smoked. Alcohol use and lifetime DSM-III-R alcohol dependence history were not associated with MAO activity when smoking was taken into account. Depression, panic disorder and social phobia showed no significant associations with platelet MAO activity. Subjects with a history of serious attempts at suicide had low platelet MAO activity; but although the difference from controls was as great as the reduction associated with smoking it was not significant after correction for smoking effects. CONCLUSIONS: Although synaptic MAO activity undoubtedly plays a role in psychopathology, the concept that platelet MAO activity is a direct genetic marker of vulnerability to alcohol dependence cannot be sustained.
Assuntos
Alcoolismo/fisiopatologia , Plaquetas/enzimologia , Doenças em Gêmeos , Transtornos Mentais/fisiopatologia , Monoaminoxidase/sangue , Fumar/fisiopatologia , Adulto , Alcoolismo/genética , Alcoolismo/psicologia , Doenças em Gêmeos/genética , Feminino , Marcadores Genéticos/genética , Predisposição Genética para Doença/genética , Humanos , Masculino , Transtornos Mentais/genética , Transtornos Mentais/psicologia , Pessoa de Meia-Idade , Escalas de Graduação Psiquiátrica , Psicopatologia , Fumar/genética , Fumar/psicologiaRESUMO
Questionnaire surveys, while more economical, typically achieve poorer response rates than interview surveys. We used data from a national volunteer cohort of young adult twins, who were scheduled for assessment by questionnaire in 1989 and by interview in 1996-2000, to identify predictors of questionnaire non-response. Out of a total of 8536 twins, 5058 completed the questionnaire survey (59% response rate), and 6255 completed a telephone interview survey conducted a decade later (73% response rate). Multinomial logit models were fitted to the interview data to identify socioeconomic, psychiatric and health behavior correlates of non-response in the earlier questionnaire survey. Male gender, education below University level, and being a dizygotic rather than monozygotic twin, all predicted reduced likelihood of participating in the questionnaire survey. Associations between questionnaire response status and psychiatric history and health behavior variables were modest, with history of alcohol dependence and childhood conduct disorder predicting decreased probability of returning a questionnaire, and history of smoking and heavy drinking more weakly associated with non-response. Body-mass index showed no association with questionnaire non-response. Despite a poor response rate to the self-report questionnaire survey, we found only limited sampling biases for most variables. While not appropriate for studies where socioeconomic variables are critical, it appears that survey by questionnaire, with questionnaire administration by telephone to non-responders, will represent a viable strategy for gene-mapping studies requiring that large numbers of relatives be screened.
Assuntos
Entrevistas como Assunto/estatística & dados numéricos , Inquéritos e Questionários/estatística & dados numéricos , Adulto , Austrália , Estudos de Coortes , Feminino , Comportamentos Relacionados com a Saúde , Humanos , Estilo de Vida , Modelos Logísticos , Masculino , Viés de Seleção , Fatores Socioeconômicos , Gêmeos/psicologiaRESUMO
BACKGROUND: We examined the relationship between childhood sexual abuse (CSA), and interviewees' recollections of pathogenic parenting, testing for possible retrospective biases in the recollections of those who have experienced CSA. METHODS: Information about CSA, parental divorce and interviewees' recollections of parental rejection, parental overprotection and perceived autonomy (as assessed through a shortened version of the Parental Bonding Instrument) was obtained through telephone interviews with 3626 Australian twins who had also returned self-report questionnaires several years earlier. Recollections of parental behaviours were compared for individuals from pairs in which neither twin, at least one twin, or both twins reported CSA. RESULTS: Significant associations were noted between CSA and paternal alcoholism and between CSA and recollections of parental rejection. For women, individuals from CSA-discordant pairs reported levels of parental rejection that were significantly higher than those obtained from CSA-negative pairs. The levels of parental rejection observed for twins from CSA-discordant pairs did not differ significantly from those obtained from CSA-concordant pairs, regardless of respondent's abuse status. For men from CSA-discordant pairs, respondents reporting CSA displayed a tendency to report higher levels of parental rejection than did respondents not reporting CSA. Other measures of parenting behaviour (perceived autonomy and parental overprotection) failed to show a clear relationship with CSA. CONCLUSIONS: The relationship between CSA and respondents' recollections of parental rejection is not due solely to retrospective bias on the part of abused individuals and, consistent with other studies, may reflect a pathological family environment with serious consequences for all siblings.
Assuntos
Abuso Sexual na Infância/psicologia , Poder Familiar , Pais/psicologia , Adulto , Fatores Etários , Idoso , Idoso de 80 Anos ou mais , Austrália , Criança , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Variações Dependentes do Observador , Estudos Retrospectivos , Fatores Sexuais , Inquéritos e QuestionáriosRESUMO
BACKGROUND: Genetic influences on alcoholism risk are well-documented in men, but uncertain in women. We tested for gender differences in genetic influences on, and risk-factors for, DSM-III-R alcohol dependence (AD). METHOD: Diagnostic follow-up interviews were conducted in 1992-3 by telephone with twins from an Australian twin panel first surveyed in 1980-82 (N = 5889 respondents). Data were analysed using logistic regression models. RESULTS: Significantly higher twin pair concordances were observed in MZ compared to DZ same-sex twin pairs in women and men, even when data were weighted to adjust for over-representation of well-educated respondents, and for selective attrition. AD risk was increased in younger birth cohorts, in Catholic males or women reporting no religious affiliation, in those reporting a history of conduct disorder or major depression and in those with high Neuroticism, Social Non-conformity, Toughmindedness, Novelty-Seeking or (in women only) Extraversion scores; and decreased in 'Other Protestants', weekly church attenders, and university-educated males. Controlling for these variables, however, did not remove the significant association with having an alcoholic MZ co-twin, implying that much of the genetic influence on AD risk remained unexplained. No significant gender difference in the genetic variance in AD was found (64% heritability, 95% confidence interval 32-73%). CONCLUSIONS: Genetic risk-factors play as important a role in determining AD risk in women as in men. With the exception of certain sociocultural variables such as religious affiliation, the same personality, sociodemographic and axis I correlates of alcoholism risk are observed in women and men.