Biomedical subjects

D J Statham

Publications and source records attributed to D J Statham.

16 recordsLinked to original sources

PubMed2002

Genetic and environmental contributions to cannabis dependence in a national young adult twin sample.

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.

Adult↗

PubMed2001

Predictors of non-response to a questionnaire survey of a volunteer twin panel: findings from the Australian 1989 twin cohort.

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.

Adult↗

PubMed2000

Monoamine oxidase: associations with alcohol dependence, smoking and other measures of psychopathology.

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.

Adult↗

PubMed2000

Childhood sexual abuse and pathogenic parenting in the childhood recollections of adult twin pairs.

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.

Adult↗

PubMed2000

A study of the genetic and environmental etiology of stuttering in a selected twin sample.

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.

Adolescent↗

PubMed2000

Anxiety and depression in twin and sib pairs extremely discordant and concordant for neuroticism: prodromus to a linkage study.

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.

Adult↗

PubMed1999

Major depressive disorder in a community-based twin sample: are there different genetic and environmental contributions for men and women?

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.

Adult↗

PubMed1999

Genetic differences in alcohol sensitivity and the inheritance of alcoholism risk.

BACKGROUND: Substantial evidence exists for an important genetic contribution to alcohol dependence risk in women and men. It has been suggested that genetically determined differences in alcohol sensitivity may represent one pathway by which an increase in alcohol dependence risk occurs. METHODS: Telephone interview follow-up data were obtained on twins from male, female and unlike-sex twin pairs who had participated in an alcohol challenge study in 1979-81, as well as other pairs from the same Australian twin panel surveyed by mail in 1980-82. RESULTS: At follow-up, alcohol challenge men did not differ from other male twins from the same age cohort on measures of lifetime psychopathology or drinking habits; but alcohol challenge omen were on average heavier drinkers than other women. A composite alcohol sensitivity measure, combining subjective intoxication and increase in body-sway after alcohol challenge in 1979-81, exhibited high heritability (60 %). Parental alcoholism history was weakly associated with decreased alcohol sensitivity in women, but not after adjustment for baseline drinking history, or in men. High alcohol sensitivity in men was associated with substantially reduced alcohol dependence risk (OR = 0.05, 95% CI 0.01-0.39). Furthermore, significantly decreased (i.e. low) alcohol sensitivity was observed in non-alcoholic males whose MZ co-twin had a history of alcohol dependence, compared to other non-alcoholics. These associations remained significant in conservative analyses that controlled for respondents' alcohol consumption levels and alcohol problems in 1979-81. CONCLUSIONS: Men (but not women) at increased genetic risk of alcohol dependence (assessed by MZ co-twin's history of alcohol dependence) exhibited reduced alcohol sensitivity. Associations with parental alcoholism were inconsistent.

Adult↗

PubMed1998

Suicidal behaviour: an epidemiological and genetic study.

BACKGROUND: Psychiatric history, familial history of suicide attempts, and certain traumatic life events are important predictors of suicidal thoughts and behaviour. We examined the epidemiology and genetics of suicidality (i.e. reporting persistent suicidal thoughts or a plan or suicide attempt) in a large community-based sample of MZ and DZ twin pairs. METHOD: Diagnostic telephone interviews were conducted in 1992-3 with twins from an Australian twin panel first surveyed in 1980-82 (N = 5995 respondents). Data were analysed using logistic regression models, taking into account twin pair zygosity and the history of suicidality in the respondent's co-twin. RESULTS: Lifetime prevalence of suicidal thoughts and attempts was remarkably constant across birth cohorts 1930-1964, and across gender. Major psychiatric correlates were history of major depression, panic disorder, social phobia in women, alcohol dependence and childhood conduct problems. Traumatic events involving assault (childhood sexual abuse, rape or physical assault) or status-loss (job loss, loss of property or home, divorce), and the personality trait neuroticism, were also significantly associated with suicide measures. Prevalence of serious suicide attempts varied as a function of religious affiliation. After controlling for these variables, however, history of suicide attempts or persistent thoughts in the respondent's co-twin remained a powerful predictor in MZ pairs (odds ratio = 3.9), but was not consistently predictive in DZ pairs. Overall, genetic factors accounted for approximately 45% of the variance in suicidal thoughts and behaviour (95% confidence interval 33-51%). CONCLUSIONS: Risk of persistent suicidal thoughts and suicide attempts is determined by a complex interplay of psychiatric history, neuroticism, traumatic life experiences, genetic vulnerability specific for suicidal behaviour and sociocultural risk or protective factors.

Adult↗

PubMed1998

Common genetic risk factors for conduct disorder and alcohol dependence.

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.

Adult↗

PubMed1997

The consistency of recalled age at first sexual intercourse.

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.

Adult↗

PubMed1997

Genetic and environmental contributions to alcohol dependence risk in a national twin sample: consistency of findings in women and men.

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.

Adult↗

PubMed1997

Modeling genetic and environmental influences in the etiology of conduct disorder: a study of 2,682 adult twin pairs.

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.

Adult↗

PubMed1997

Participation bias in a sexuality survey: psychological and behavioural characteristics of responders and non-responders.

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.

Adolescent↗

PubMed1997

Nicotine withdrawal in women.

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.

Adult↗

PubMed1996

Reliability and reporting biases for perceived parental history of alcohol-related problems: agreement between twins and differences between discordant pairs.

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.

Adult↗