Living with chronic hepatitis C means 'you just haven't got a normal life any more'

OBJECTIVE

To explore psychosocial factors that impact on quality of life for people living with self-reported chronic hepatitis C.

METHODS

A purposeful sample of 70 people who were self-identified as being hepatitis C virus (HCV)-positive was recruited through a variety of institutions and community agencies. Semi-structured interviews were held with 12 groups and 21 individuals. A qualitative grounded-theory methodology was used for data collection and analysis. Experiences of physical and psychological symptoms, stigma and discrimination, and living with an infectious disease, were explored using matrices.

RESULTS

Phenomena emerging from the data included previously undocumented illness 'attacks' that were associated with depressive symptoms and a perception of hepatitis C as fatal. Uncertainty related to disease progression and transmission of the virus were common experiences among participants. A universal experience was fear and anxiety about stigma and discrimination.

DISCUSSION

The findings of this study indicate that chronic hepatitis C has a pervasive impact on quality of life with a complexity that has not been explored with quantitative research approaches. Primary healthcare professionals need to be alert to the psychological and social impacts of chronic hepatitis C and to avoid behaviours that lead to perceptions of stigma and discrimination. The research indicates a need for further investigation into the relationship between psychosocial factors, disease management and disease progression.

Health and demographic characteristics of respondents in an Australian national sexuality survey: comparison with population norms

STUDY OBJECTIVE

To assess the representativeness of survey participants by systematically comparing volunteers in a national health and sexuality survey with the Australian population in terms of self reported health status (including the SF-36) and a wide range of demographic characteristics.

DESIGN

A cross sectional sample of Australian residents were compared with demographic data from the 1996 Australian census and health data from the 1995 National Health Survey.

SETTING

The Australian population.

PARTICIPANTS

A stratified random sample of adults aged 18-59 years drawn from the Australian electoral roll, a compulsory register of voters. Interviews were completed with 1784 people, representing 40% of those initially selected (58% of those for whom a valid telephone number could be located).

MAIN RESULTS

Participants were of similar age and sex to the national population. Consistent with prior research, respondents had higher socioeconomic status, more education, were more likely to be employed, and less likely to be immigrants. The prevalence estimates, means, and variances of self reported mental and physical health measures (for example, SF-36 subscales, women's health indicators, current smoking status) were similar to population norms.

CONCLUSIONS

These findings considerably strengthen inferences about the representativeness of data on health status from volunteer samples used in health and sexuality surveys.

Health-related quality of life following podiatric surgery

This 6-month prospective study investigated the outcomes of foot surgery performed by Fellows of the Australian College of Podiatric Surgeons. The study recruited 140 patients who were treated for orthopedic, neurological, or integumentary diseases of the foot. The majority of subjects who underwent podiatric surgery experienced significant postoperative improvements in a range of health-related quality-of-life dimensions as measured by the disease-specific Foot Health Status Questionnaire (FHSQ) and the generic Short Form 36 (SF-36) questionnaire. Subjects reported a reduction in foot pain, increased levels of physical function, improved general foot health perception, and improved footwear-related quality of life. No significant adverse outcomes or unplanned re-admissions to the hospital were reported. This study demonstrates the advantage of assessing health-related quality of life as opposed to patient satisfaction.

The subtlety of sex-atypicality

Memories of sex-atypical behavior and interests in childhood usually differ between homosexual and heterosexual people. However, variation within these broad groups has not previously been explored in detail, especially among women. We utilized data from a postal survey of a nationwide sample of Australian adult twins (n = 4,901, age range: 19-52 years). Among men, 15.2% reported homosexual behavior (ever), 11.5% said they had been sexually attracted to the same sex, and 6.4% said they were not heterosexual; the corresponding figures for women were 7.9, 10.6, and 3.5%. A continuous measure of childhood gender nonconformity (CGN) was sensitive to slight variations in homosexual attraction and behavior. In particular, among both men and women who identified as heterosexual, there were significant differences between "complete" heterosexuals and those who admitted to only one or a few same-sex behaviors but no homosexual attraction. Among men, CGN scores distinguished between heterosexuals who admitted to same-sex behavior only and those who admitted to some homosexual attraction. The sexual subgroups also differed on a measure of gender atypicality in adulthood. Implications for developmental theories of sexuality are discussed.

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.

Substance use by indigenous and non-indigenous primary school students

OBJECTIVE

Recent Australian research with adolescents aged 13 to 17 years has found that Indigenous youth are more likely than non-Indigenous adolescents to smoke tobacco and cannabis, although they may be less likely to use alcohol. The objective of this study was to examine whether this pattern exists among younger children.

METHOD

A school-based, self-report survey was conducted in primary schools that had high proportions of Aboriginal and Torres Strait Islander children. Four schools were located in metropolitan Brisbane and three in Far North Queensland (sample n = 507 students: 270 girls, 237 boys, aged 9-13 years).

RESULTS

Significant numbers of these children had started to experiment with recreational drugs. Twenty-two per cent had attempted to smoke at least one cigarette, 14% smoked in the preceding year, while 3% had smoked more than 10 cigarettes in their lives. Thirty-eight per cent had had at least one drink of alcohol, while 6% had smoked marijuana at least once. There was no significant association between Indigenous/non-Indigenous background and risk of smoking tobacco or marijuana, while Indigenous children were less likely than non-Indigenous children to report experience with alcohol.

CONCLUSIONS

Contrary to data from secondary school students, Indigenous youth in primary schools were not more likely than non-Indigenous children to have experimented with tobacco or marijuana, or to be frequent tobacco smokers. It appears therefore that the excessive uptake of drug use among Indigenous youth occurs in the early stages of secondary school. This finding underlines the importance of preventive education in primary schools, especially for Indigenous children who have a high risk of making the transition to drug use in adolescence.

Measurement models for sexual orientation in a community twin sample

Multivariate structural equation modeling techniques have been applied to examine the causes of individual differences in responses to several items concerning sexual orientation. To minimize potential ascertainment and response biases, the study sample involved a large (N = 4901) community-based cohort of Australian twins aged 18-52 who answered an anonymous questionnaire on sexual behavior and attitudes. The statistical power of the analysis was increased by the availability of multiple measures of sexual orientation (behaviors, attitudes and feelings), providing stronger evidence for the existence of additive genetic influences on this phenotype than in a previous analysis (Bailey et al., 2000). Estimates of the heritability of homosexuality in this sample ranged between 50 and 60% in females but were significantly lower (heritability of approximately 30%) in males.

Do individual differences in sociosexuality represent genetic or environmentally contingent strategies? Evidence from the Australian twin registry

Although men are substantially more interested than women in casual sex, there is ample variation in this trait (sociosexuality) within both sexes. One theory hypothesizes that within-sex sociosexual variation results from genetic variation maintained by frequency-dependent selection. If so, sociosexuality should be substantially heritable. A competing theory is that children acquire their mating strategy after observing their parents' relationship. By this theory, sociosexuality should reveal a strong shared environmental component. The authors studied genetic and environmental influences on sociosexuality using a large, representative volunteer twin sample. Parental marital instability was modestly associated with sociosexuality, but this could have been due to either genetic or environmental factors. Consistent with genetic theory, familial resemblance appeared primarily due to additive genetic rather than shared environmental factors.

Genetic and environmental influences on sexual orientation and its correlates in an Australian twin sample

We recruited twins systematically from the Australian Twin Registry and assessed their sexual orientation and 2 related traits: childhood gender nonconformity and continuous gender identity. Men and women differed in their distributions of sexual orientation, with women more likely to have slight-to-moderate degrees of homosexual attraction, and men more likely to have high degrees of homosexual attraction. Twin concordances for nonheterosexual orientation were lower than in prior studies. Univariate analyses showed that familial factors were important for all traits, but were less successful in distinguishing genetic from shared environmental influences. Only childhood gender nonconformity was significantly heritable for both men and women. Multivariate analyses suggested that the causal architecture differed between men and women, and, for women, provided significant evidence for the importance of genetic factors to the traits' covariation.

Do individual differences in sociosexuality represent genetic or environmentally contingent strategies? Evidence from the Australian twin registry

Although men are substantially more interested than women in casual sex, there is ample variation in this trait (sociosexuality) within both sexes. One theory hypothesizes that within-sex sociosexual variation results from genetic variation maintained by frequency-dependent selection. If so, sociosexuality should be substantially heritable. A competing theory is that children acquire their mating strategy after observing their parents' relationship. By this theory, sociosexuality should reveal a strong shared environmental component. The authors studied genetic and environmental influences on sociosexuality using a large, representative volunteer twin sample. Parental marital instability was modestly associated with sociosexuality, but this could have been due to either genetic or environmental factors. Consistent with genetic theory, familial resemblance appeared primarily due to additive genetic rather than shared environmental factors.

Genetic and environmental influences on sexual orientation and its correlates in an Australian twin sample

We recruited twins systematically from the Australian Twin Registry and assessed their sexual orientation and 2 related traits: childhood gender nonconformity and continuous gender identity. Men and women differed in their distributions of sexual orientation, with women more likely to have slight-to-moderate degrees of homosexual attraction, and men more likely to have high degrees of homosexual attraction. Twin concordances for nonheterosexual orientation were lower than in prior studies. Univariate analyses showed that familial factors were important for all traits, but were less successful in distinguishing genetic from shared environmental influences. Only childhood gender nonconformity was significantly heritable for both men and women. Multivariate analyses suggested that the causal architecture differed between men and women, and, for women, provided significant evidence for the importance of genetic factors to the traits' covariation.

Early sexual abuse and lifetime psychopathology: a co-twin-control study

BACKGROUND

This study was designed to determine lifetime prevalence of psychiatric disorders among twins who reported childhood sexual abuse (CSA), and to compare these rates with those among non-abused co-twins. The contribution of familial and individual-specific factors to reported sexual abuse was also examined.

METHOD

Information about lifetime psychopathology and substance use was obtained by structured telephone interviews with 5995 Australian twins. Twins who reported a history of childhood sexual abuse (CSA) were contrasted on lifetime psychopathology with subjects without such a history; in addition, comparisons were made between same-sex twin pairs discordant for CSA.

RESULTS

A history of CSA was reported by 5.9% of the women and 2.5% of the men. In the sample as a whole, those reporting CSA were more likely to receive lifetime diagnoses of major depression, conduct disorder, panic disorder and alcoholism, and were more likely to report suicidal ideation and a history of suicide attempt. Abused women, but not men, were also more likely to report social phobia. When comparisons were restricted to non-abused co-twins, no differences in psychopathology were seen. However, rates of major depression, conduct disorder and suicidal ideation were higher if both co-twins were abused than if the respondent alone reported CSA. Model-fitting indicated that shared environmental factors influenced risk for reported CSA in women, but not in men.

CONCLUSION

The association between CSA and psychopathology arises at least in part through the influence of shared familial factors on both risk of victimization and risk of psychopathology.

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.

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.

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.

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.

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.

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.

Psychological distress among female sex workers

The prevalence and correlates of psychological distress were examined in a sample of 171 female sex workers in Queensland. It was found that 28 per cent were above the GHQ-28 threshold for mild psychiatric morbidity, a rate that is not appreciably different from that of women in the general community. The sample included only eight street sex workers, all of whom reported significant distress. Logistic regression analyses showed that a history of injecting drug use, an early age at leaving home and wanting to leave the sex industry were independent predictors of poor mental health. Distressed sex workers reported fewer sexual health examinations and less consistent condom use with their clients than those who were not distressed.

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.

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.

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.

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.

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.

A genetic aetiology for some common dental anomalies: a pilot twin study

This pilot study investigated the aetiology of various dental anomalies. Twin-pair correlations were obtained for the total number of missing, ectopic, malformed and rotated permanent teeth which were scored from panoramic radiographs of 59 monozygotic (identical) and 42 dizygotic (non-identical) twin-pairs. All monozygotic (MZ) twin correlations were greater than the dizygotic (DZ) twin correlations, suggesting a significant hereditary aetiology. A familial history of such common dental anomalies could become a valuable asset in treatment planning.

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.

Psychological and social correlates of attrition in a longitudinal study of hazardous waste exposure

The differences between responders and nonresponders ("re(fuser)s" and "movers") in a follow-up survey of self-reported health effects associated with residing near a hazardous waste site were analyzed in this study. Responders and refusers did not differ with respect to demographic variables when comparison was made with measures from the initial survey; however, movers were more likely than refusers to be younger, to rent their homes, and to have lived in the area for the shortest period. In terms of psychological reactions, movers and refusers reported more intense worries, more stress, and more psychological intrusion about the problem than did responders. There were no differences between the groups with respect to self-reported prevalence of death and cancer, diseases, or symptoms of physical illness. The results indicated that the psychological impact of exposure to a hazardous waste site may be greatest in individuals who are lost to follow-up.

Is alcohol-related flushing a protective factor for alcoholism in Caucasians?

Although alcohol-related flushing seems to be a genetically influenced protective factor for alcoholism in some Asian groups, little is known about whether this is true for Caucasians. The evidence for alcohol-related flushing as a protective factor for the development of alcoholism was examined in a sample of 5831 Australian twins (2041 men, 3790 women) who were administered a structured psychiatric interview. Twin correlations for self-reported adverse alcohol reactions (e.g., "flushing or blushing" and "feeling very sleepy" after drinking 1 or 2 drinks) were modest, suggesting minimal contribution of genetic factors, but when corrected for reliability of measurement, were consistent with moderate heritabilities. In accord with studies examining Asian samples, we found that individuals who experienced adverse reactions after drinking small amounts of alcohol drank less often and slightly less per drinking occasion than those who did not experience adverse reactions. However, those who experienced adverse reactions were more likely to have symptoms of alcoholism and to report a parental history of alcohol problems. We conclude that self-reported alcohol-related flushing is not a protective factor for alcoholism in Caucasians and may be a risk factor.

Religiosity, sexual intercourse and condom use among university students

There is strong evidence that religiosity among adolescents is associated with delayed onset of sexual activity. However, research on relationships between religiosity and contraceptive practices is limited and inconsistent. This paper provides data from a survey of 374 students aged between 16 and 21 at two Brisbane universities (72.4 per cent response rate). Those who perceived religion to be important in their lives were less likely to have had intercourse. Among the sexually active sample, religious youth did not differ from their peers in recent condom use, the age at which they first used condoms or the rate of partner change. Contrary to several recent assertions in review articles, this and other empirical studies do not show that religious youth are less likely than nonreligious youth to take precautions during sex.

Age-related increase in sexual behaviours and decrease in regular condom use among adolescents in Australia

The prevalence of sexual behaviours was estimated from a survey of 3854 Australian secondary school students. Self-reported prevalence of intercourse increased from 9.9% (age 13 years or less) to 23.9% (age 15) and 51.2% at age 17 and over. Among 932 sexually experienced youth in the final 3 years of secondary school, 26% of males and 18% of females reported having 3 or more partners in the previous year; 89.4% had used a condom at least once, with males (71.8%) reporting more last occasion condom use than females (53.4%). 'Last occasion' and 'usual', but not lifetime, condom use was significantly lower among older respondents. Although nearly 90% of females in each of 3 age groups reported lifetime condom use, just 27.6% of female students aged 17 or more reported that condoms were always used during intercourse. The decline with age, noted in research with adults and older adolescents, may begin in the middle teens.

Further evidence that scopolamine can improve verbal fluency

Scopolamine usually is found to impair various aspects of human cognitive performance. Recently, however, a significant (though modest) improvement in verbal fluency has been reported following scopolamine hydrobromide (0.6 and 1.2 mg p.o.). This study replicated that effect, finding significantly better FAS letter fluency in contrast to poorer performance on other neuropsychological measures following sub cutaneous injection of 0.4 mg scopolamine. Data are discussed in terms of a functional state model of drug action.

Psychological distress and psychiatric morbidity in women prisoners

The population of a women's prison (n = 92) was screened for psychological distress and psychiatric morbidity with the 12-item General Health Questionnaire, the Hamilton Depression Rating Scale, a Recent Stressful Life Events questionnaire and the Structured Clinical Interview for DSM-III-R. High levels of symptoms of psychological distress were recorded. Distress was correlated with recent stressful life events and was more severe in women awaiting trial. Fifty-three per cent of the prisoners were diagnosed as current cases of a psychiatric disorder and the most frequent diagnoses were adjustment disorder with depressed mood and personality disorders. Lifetime prevalence of psychoactive substance use disorders was 54 per cent. Aboriginal women were over-represented in this prison population. A follow-up survey after 4 months showed no fall in the prevalence of psychological distress and psychiatric morbidity.

Australian suicide data and the use of "undetermined" death category (1968-1985)

There has been considerable recent debate about the impact that changes in the use of the "undetermined" death classification may have upon trends in national suicide statistics. This study focused on changes over time within each state in Australia in an attempt to determine the source of apparent patterns in national data. Considerable intra- and inter-state variability was revealed, and it was concluded that, apart from a general trend for decreasing use of the undetermined category, the data are not of sufficient quantity to warrant further interpretation. The suggestion that changes in classification practices by coroners may have contributed to the rise in young male suicides was not supported.

The health effects of chemical waste in an urban community

This paper presents the results of a community health survey of people living near a hazardous chemical waste site in Kingston, Queensland. In comparison with a matched control group, people near the site were no more likely to report serious diseases, and reports of cancer and mortality rates did not differ in the two groups. Kingston residents reported higher rates of symptoms of general poor health, high levels of stress and anxiety and a higher incidence of miscarriages. The reports of poor physical health appear to be independent of proximity to the hazardous waste site and duration of residence in the area. Symptom prevalence and perceived recent decline in health correlate most strongly with the stress and anxiety measures. While long-term investigation is necessary, it appears at this stage that the chemical waste is not associated with an increase in major diseases as reported by those who were interviewed. When health in a broader sense is considered, however, it is clear that the situation has had a negative impact.

Scopolamine and sustained retrieval from semantic memory

Two experiments were conducted to examine the effects of 0.9 mg oral sco polamine on continuous retrieval of items from natural semantic categories. In experiment 1, scopolamine increased the frequency of item repetition, but had no effect on the number of items subjects could retrieve, or the number of items retrieved per retrieval cue. Experiment 2 introduced a variant of this task where subjects could either retrieve items freely using any preferred strategy, or were constrained to a single retrieval strategy. Again, scopolamine did not impair retrieval of items from semantic categories. It was argued that these negative results are unlikely to be the product of low experimental power, and that the data are consistent with the view that the effects of scopolamine are limited to information acquisition, at least in healthy young subjects.

Scopolamine and the control of attention in humans

Recent work with humans and animals has suggested that the cholinergic system plays an important role in the active control of attention. This study was designed to investigate the effects of scopolamine upon subjects' ability to utilize knowledge of the spatial probability bias in a display in the detection of briefly-presented target letters. Results showed a significant interaction between drug condition (scopolamine 0.9 mg versus Placebo) and target location probability, which indicated that detection of targets in high probability locations decreased under the drug, while detection in low probability locations increased. These results offer support for the notion that scopolamine reduces the efficiency of information encoding because it impairs the optimal utilization of attentional resources.