Linking the serotonin transporter gene, family environments, hippocampal volume and depression onset: A prospective imaging gene × environment analysis

A single imaging gene-environment (IGxE) framework that is able to simultaneously model genetic, neurobiological, and environmental influences on psychopathology outcomes is needed to improve understanding of how complex interrelationships between allelic variation, differences in neuroanatomy or neuroactivity, and environmental experience affect risk for psychiatric disorder. In a longitudinal study of adolescent development we demonstrate the utility of such an IGxE framework by testing whether variation in parental behavior at age 12 altered the strength of an imaging genetics pathway, involving an indirect association between allelic variation in the serotonin transporter gene to variation in hippocampal volume and consequent onset of major depressive disorder by age 18. Results were consistent with the presence of an indirect effect of the serotonin transporter S-allele on depression onset via smaller left and right hippocampal volumes that was significant only in family environments involving either higher levels of parental aggression or lower levels of positive parenting. The previously reported finding of S-allele carriers' increased risk of depression in adverse environments may, therefore, be partly because of the effects of these environments on a neurobiological pathway from the serotonin transporter gene to depression onset that proceeds through variation in hippocampal volume.

Perinatal maternal alcohol consumption and methylation of the dopamine receptor DRD4 in the offspring: the Triple B study

Maternal alcohol use during the perinatal period is a major public health issue, the higher ends of which are associated with foetal alcohol spectrum disorder and a range of adverse health outcomes in the progeny. The underlying molecular mechanisms remain largely unknown but may include the epigenetic disruption of gene activity during development. Alcohol directly activates the neurotransmitter dopamine, which plays an essential role in neurodevelopment. To investigate whether antenatal and early postnatal alcohol consumption were associated with differential dopamine receptor DRD4 promoter methylation in infants (n = 844). Data were drawn from the large population based Triple B pregnancy cohort study, with detailed information on maternal alcohol consumption in each trimester of pregnancy and early postpartum. DNA was extracted from infant buccal swabs collected at 8-weeks. DRD4 promoter DNA methylation was analysed by Sequenom MassARRAY. No strong evidence was found for an association between alcohol consumption during pregnancy and infant DRD4 methylation at 8-weeks postpartum. However, maternal alcohol consumption assessed contemporaneously at 8-weeks postpartum was associated with increased methylation at 13 of 19 CpG units examined (largest Δ + 3.20%, 95%Confidence Interval:1.66,4.75%, P = 0.0001 at CpG.6). This association was strongest in women who breastfeed, suggesting the possibility of a direct effect of alcohol exposure via breast milk. The findings of this study could influence public health guidelines around alcohol consumption for breastfeeding mothers; however, further research is required to confirm these novel findings.

The natural history of internalizing behaviours from adolescence to emerging adulthood: findings from the Australian Temperament Project

BACKGROUND

The aims of the study were to describe the patterning and persistence of anxiety and depressive symptoms from adolescence to young adulthood and to examine long-term developmental relationships with earlier patterns of internalizing behaviours in childhood.

METHOD

We used parallel processes latent growth curve modelling to build trajectories of internalizing from adolescence to adulthood, using seven waves of follow-ups (ages 11-27 years) from 1406 participants of the Australian Temperament Project. We then used latent factors to capture the stability of maternal reported child internalizing symptoms across three waves of early childhood follow-ups (ages 5, 7 and 9 years), and examined relationships among these patterns of symptoms across the three developmental periods, adjusting for gender and socio-economic status.

RESULTS

We observed strong continuity in depressive symptoms from adolescence to young adulthood. In contrast, adolescent anxiety was not persistent across the same period, nor was it related to later depressive symptoms. Anxiety was, however, related to non-specific stress in young adulthood, but only moderately so. Although childhood internalizing was related to adolescent and adult profiles, the associations were weak and indirect by adulthood, suggesting that other factors are important in the development of internalizing symptoms.

CONCLUSIONS

Once established, adolescent depressive symptoms are not only strongly persistent, but also have the potential to differentiate into anxiety in young adulthood. Relationships with childhood internalizing symptoms are weak, suggesting that early adolescence may be an important period for targeted intervention, but also that further research into the childhood origins of internalizing behaviours is needed.

The effect of low parental warmth and low monitoring on disordered eating in mid-adolescence: Findings from the Australian Temperament Project

OBJECTIVE

To investigate the interactions between low parental warmth and monitoring at age 13-14 years and disordered eating attitudes and behaviours at age 15-16 years.

METHOD

Data on 1300 (667 females) adolescents and their parents were drawn from The Australian Temperament Project (ATP), a 30 year (15 wave) population based longitudinal study of social-emotional development. Parent participants completed surveys on parenting practices in late childhood, and adolescent participants reported disordered eating using the drive for thinness and bulimia subscales of the Eating Disorder Inventory (EDI) and an additional body dissatisfaction scale. Interaction was examined on the additive scale by estimating super-additive risk; i.e., risk in excess of the sum of individual risks.

RESULTS

For boys, neither parental warmth or monitoring, nor their interaction, was related to disordered eating. For girls, low parental warmth (alone) was associated with bulimic behaviours. In contrast, exposure to both low monitoring and warmth was associated with ∼3½-fold, ∼4-fold and ∼5-fold increases in the odds of reporting body dissatisfaction, drive for thinness and bulimia, respectively. For body dissatisfaction and drive for thinness, risk associated with joint exposure exceeded the sum of individual risks, suggesting an additive interaction between parenting styles.

CONCLUSION

Further investment in family-level interventions that focus on promoting parental monitoring behaviour and a warm parent-child relationship remain important strategies for preventing a range of disordered eating behaviours in adolescents.

Predictors of postnatal mother-infant bonding: the role of antenatal bonding, maternal substance use and mental health

The emotional bond that a mother feels towards her baby is critical to social, emotional and cognitive development. Maternal health and wellbeing through pregnancy and antenatal bonding also play a key role in determining bonding postnatally, but the extent to which these relationships may be disrupted by poor mental health or substance use is unclear. This study aimed to examine the extent to which mother-fetal bonding, substance use and mental health through pregnancy predicted postnatal mother-infant bonding at 8 weeks. Participants were 372 women recruited from three metropolitan hospitals in Australia. Data was collected during trimesters one, two and three of pregnancy and 8 weeks postnatal using the Maternal Antenatal Attachment Scale (MAAS), Maternal Postnatal Attachment Scale (MPAS), the Edinburgh Antenatal and Postnatal Depression Scale (EPDS), the Depression and Anxiety Scales (DASS-21), frequency and quantity of substance use (caffeine, alcohol and tobacco) as well as a range of demographic and postnatal information. Higher antenatal bonding predicted higher postnatal bonding at all pregnancy time-points in a fully adjusted regression model. Maternal depressive symptoms in trimesters two and three and stress in trimester two were inversely related to poorer mother-infant bonding 8 weeks postnatally. This study extends previous work on the mother's felt bond to her developing child by drawing on a large sample of women and documenting the pattern of this bond at three time points in pregnancy and at 8 weeks postnatally. Utilising multiple antenatal waves allowed precision in isolating the relationships in pregnancy and at key intervention points. Investigating methods to enhance bonding and intervene in pregnancy is needed. It is also important to assess maternal mental health through pregnancy.

Early origins of mental disorder - risk factors in the perinatal and infant period

BACKGROUND

There is increasing understanding of the significance of early neurodevelopment in establishing risk for the range of mental disorders. Models of the early aetiology of mental disorders are complex with a range of potential factors from genetic and epigenetic to environmental influencing neurological and psychological development. Whilst the mechanisms are not fully understood, this paper provides an overview of potential biological and neurobiological factors that might be involved.

METHOD

An aetiological model is presented and discussed. The discussion includes a range of risk factors for mental disorder. Maternal anxiety disorder is presented and reviewed as an example of the interaction of placental, epigenetic and early parenting factors elevating risk of poor neonatal outcome.

RESULTS

Available evidence points to the importance of in-utero influences as well as the role of early attachment and emotional care. Transgenerational mechanisms such as the impact of maternal mental disorder on foetal development are important models for examination of early risk. Maternal anxiety, as an example, is a significant risk factor for compromised mental health.

CONCLUSIONS

Development of models for understanding the early origins of mental disorder is an important step in elaborating risk reduction strategies. Comprehensive early identification of risk raises the possibility of preventive interventions.

Associations between parent-child relationship quality and obesogenic risk in adolescence: a systematic review of recent literature

Adolescence is a period of significant cognitive, social and physiological change, presenting unique risk factors for weight gain. Childhood obesity research has traditionally focused on the influence of parent-level factors on children's eating and weight status. Increasingly, emphasis is turning towards the reciprocal nature of the parent-child relationship and its influence on health behaviour. A systematic literature review was conducted to investigate the relationship between parent-child relationship quality (defined as the felt emotional bond between parent and child) and obesogenic risk (weight status, eating attitudes and behaviours, level of physical activity and sedentary behaviour) in adolescence; 26 papers were included in the review. The results neither support nor challenge an association between parent-child relationship quality and weight, with study design flaws and limited measurement of the parent-child relationship precluding robust conclusions. The review does however suggests that several aspects of the parent-child relationship are important in understanding eating attitudes and behaviours, including the felt emotional bond between the parent and child, the child's perception of how much the parent cares for them and the mother's sensitivity towards the child. The need for further longitudinal research into the association between parent-child relationship quality and obesity risk across this developmental period is discussed.

Drinking patterns of adolescents who develop alcohol use disorders: results from the Victorian Adolescent Health Cohort Study

OBJECTIVE

We identify drinking styles that place teens at greatest risk of later alcohol use disorders (AUD).

DESIGN

Population-based cohort study.

SETTING

Victoria, Australia.

PARTICIPANTS

A representative sample of 1943 adolescents living in Victoria in 1992.

OUTCOME MEASURES

Teen drinking was assessed at 6 monthly intervals (5 waves) between mean ages 14.9 and 17.4 years and summarised across waves as none, one, or two or more waves of: (1) frequent drinking (3+ days in the past week), (2) loss of control over drinking (difficulty stopping, amnesia), (3) binge drinking (5+ standard drinks in a day) and (4) heavy binge drinking (20+ and 11+ standard drinks in a day for males and females, respectively). Young Adult Alcohol Use Disorder (AUD) was assessed at 3 yearly intervals (3 waves) across the 20s (mean ages 20.7 through 29.1 years).

RESULTS

We show that patterns of teen drinking characterised by loss of control increase risk for AUD across young adulthood: loss of control over drinking (one wave OR 1.4, 95% CI 1.1 to 1.8; two or more waves OR 1.9, CI 1.4 to 2.7); binge drinking (one wave OR 1.7, CI 1.3 to 2.3; two or more waves OR 2.0, CI 1.5 to 2.6), and heavy binge drinking (one wave OR 2.0, CI 1.4 to 2.8; two or more waves OR 2.3, CI 1.6 to 3.4). This is not so for frequent drinking, which was unrelated to later AUD. Although drinking was more common in males, there was no evidence of sex differences in risk relationships.

CONCLUSIONS

Our results extend previous work by showing that patterns of drinking that represent loss of control over alcohol consumption (however expressed) are important targets for intervention. In addition to current policies that may reduce overall consumption, emphasising prevention of more extreme teenage bouts of alcohol consumption appears warranted.

Associations between dehydroepiandrosterone (DHEA) levels, pituitary volume, and social anxiety in children

Early timing of adrenarche, associated with relatively high levels of dehydroepiandrosterone (DHEA) and its sulphate (DHEA-S) in children, has been linked with mental health problems, particularly anxiety. However, little is known about possible neurobiological mechanisms underlying this association. The pituitary gland is a key component of the hypothalamic-pituitary-adrenal (HPA) axis, the activation of which triggers the onset of adrenarche. The purpose of this study was to examine the extent to which pituitary gland volume mediated the relationship between levels of DHEA/DHEA-S relative to age (i.e., adrenarcheal timing) and symptoms of anxiety in 95 children (50 female, M age 9.50 years, SD 0.34 years). Relatively high DHEA and DHEA-S (DHEA/S) levels were found to be associated with larger pituitary gland volumes. There was no significant direct effect of relative DHEA/S levels on overall symptoms of anxiety. However, results supported an indirect link between relatively high DHEA/S levels and symptoms of social anxiety, mediated by pituitary gland volume. No sex differences were observed for any relationship. Our findings suggest that neurobiological mechanisms may be partly responsible for the link between relatively early adrenarche and anxiety symptoms in children. One possible mechanism for this finding is that an enlarged pituitary gland in children experiencing relatively advanced adrenarche might be associated with hyper-activity/reactivity of the HPA axis. Further research is needed to understand the role of stress in the link between adrenarcheal timing and HPA-axis function, especially in relation to the development of anxiety symptoms in children and adolescents.

The lifetime experience of traumatic events is associated with hair cortisol concentrations in community-based children

Adversity early in life can disrupt the functioning of the hypothalamic-pituitary-adrenal axis (HPAA) and increase risk for negative health outcomes. Recent research suggests that cortisol in scalp hair represents a promising measure of HPAA function. However, little is known about the relationship between early exposure to traumatic events and hair cortisol concentrations (HCC) in childhood, a critical period of HPAA development. The current study measured HCC in scalp hair samples collected from 70 community-based children (14 males, mean age=9.50) participating in the Imaging Brain Development in the Childhood to Adolescence Transition Study (iCATS). Data were also collected on lifetime exposure to traumatic events and current depressive symptoms. Lifetime exposure to trauma was associated with elevated HCC; however, HCC was not associated with current depressive symptoms. Consistent with some prior work, males were found to have higher HCC than females, although results should be treated with caution due to the small number of males who took part. Our findings suggest that hair cortisol may represent a biomarker of exposure to trauma in this age group; however, further study is necessary with a particular focus on the characterization of trauma and other forms of adversity.

Relationships between problematic alcohol consumption and delinquent behaviour from adolescence to young adulthood

BACKGROUND

Heavy episodic drinking (HED) has been associated with increased risk for short- and long-term injury and harms, such as violence and delinquent behaviour; however, the temporal relationship between the two remains unclear, particularly on transition to young adulthood. This study investigates transactional pathways between HED and delinquent behaviour from adolescence to emerging adulthood.

METHODS

Data were drawn from the Australian Temperament Project; a population-based longitudinal study that has followed the health and development of participants (and parents) across 30 years from birth in 1982. The analytic sample was 1650 participants and included five measurement waves spanning adolescence (3 waves: 13-18 years) and young adulthood (2 waves; 19-24 years).

RESULTS

There was strong continuity across waves of both HED and delinquency, as well as across-time associations between them. Delinquent behaviour in adolescence was associated with up to twofold increases in the odds of HED at each subsequent adolescent wave. HED in the late teens was associated with over fourfold increases in the odds of persistent (two waves) HED in young adulthood. HED in the late teens was associated with increases in the odds of delinquent behaviour in young adulthood (over twofold for male and one and a half-fold for female participants).

CONCLUSIONS

While delinquent behaviour predicts both future HED and future delinquent behaviour in adolescence, once young people reach the legal drinking age of 18 years, HED becomes a predictor of current and future delinquent behaviour and future HED, suggesting that increased access to alcohol increases the likelihood of young people engaging in delinquent behaviour. [Miller PG, Butler E, Richardson B, Staiger PK, Youssef GJ, Macdonald JA, Sanson A, Edwards B, Olsson CA. Relationships between problematic alcohol consumption and delinquent behaviour from adolescence to young adulthood. Drug Alcohol Rev 2016;35:317-325].

Associations between early adrenarche, affective brain function and mental health in children

Early timing of adrenarche, associated with relatively high levels of Dehydroepiandrosterone (DHEA) in children, has been associated with mental health and behavioral problems. However, little is known about effects of adreneracheal timing on brain function. The aim of this study was to investigate the effects of early adrenarche (defined by high DHEA levels independent of age) on affective brain function and symptoms of psychopathology in late childhood (N = 83, 43 females, M age 9.53 years, s.d. 0.34 years). Results showed that higher DHEA levels were associated with decreased affect-related brain activity (i) in the mid-cingulate cortex in the whole sample, and (ii) in a number of cortical and subcortical regions in female but not male children. Higher DHEA levels were also associated with increased externalizing symptoms in females, an association that was partly mediated by posterior insula activation to happy facial expressions. These results suggest that timing of adrenarche is an important moderator of affect-related brain function, and that this may be one mechanism linking early adrenarche to psychopathology.

Developmental antecedents of abnormal eating attitudes and behaviors in adolescence

OBJECTIVE

This study capitalizes on developmental data from an Australian population-based birth cohort to identify developmental markers of abnormal eating attitudes and behaviors in adolescence. The aims were twofold: (1) to develop a comprehensive path model identifying infant and childhood developmental correlates of Abnormal Eating Attitudes and Behaviors in adolescence, and (2) to explore potential gender differences.

METHOD

Data were drawn from a 30-year longitudinal study that has followed the health and development of a population based cohort across 15 waves of data collection from infancy since 1983: The Australian Temperament Project. Participants in this analysis were the 1,300 youth who completed the 11th survey at 15-16 years (1998) and who completed the eating disorder inventory at this time point.

RESULTS

Developmental correlates of Abnormal Eating Attitudes and Behaviors in mid-adolescence were temperamental persistence, early gestational age, persistent high weight, teen depression, stronger peer relationships, maternal dieting behavior, and pubertal timing. Overall, these factors accounted for 28% of the variance in Abnormal Eating Attitudes and Behaviors at 15-16 years of age. Depressive symptoms, maternal dieting behavior, and early puberty were more important factors for girls. Late puberty was a more important factor for boys.

DISCUSSION

Findings address an important gap in our understanding of the etiology of Abnormal Eating Attitudes and Behaviors in adolescence and suggest multiple targets for preventive intervention.

Young adult sequelae of adolescent cannabis use: an integrative analysis

BACKGROUND

Debate continues about the consequences of adolescent cannabis use. Existing data are limited in statistical power to examine rarer outcomes and less common, heavier patterns of cannabis use than those already investigated; furthermore, evidence has a piecemeal approach to reporting of young adult sequelae. We aimed to provide a broad picture of the psychosocial sequelae of adolescent cannabis use.

METHODS

We integrated participant-level data from three large, long-running longitudinal studies from Australia and New Zealand: the Australian Temperament Project, the Christchurch Health and Development Study, and the Victorian Adolescent Health Cohort Study. We investigated the association between the maximum frequency of cannabis use before age 17 years (never, less than monthly, monthly or more, weekly or more, or daily) and seven developmental outcomes assessed up to age 30 years (high-school completion, attainment of university degree, cannabis dependence, use of other illicit drugs, suicide attempt, depression, and welfare dependence). The number of participants varied by outcome (N=2537 to N=3765).

FINDINGS

We recorded clear and consistent associations and dose-response relations between the frequency of adolescent cannabis use and all adverse young adult outcomes. After covariate adjustment, compared with individuals who had never used cannabis, those who were daily users before age 17 years had clear reductions in the odds of high-school completion (adjusted odds ratio 0·37, 95% CI 0·20-0·66) and degree attainment (0·38, 0·22-0·66), and substantially increased odds of later cannabis dependence (17·95, 9·44-34·12), use of other illicit drugs (7·80, 4·46-13·63), and suicide attempt (6·83, 2·04-22·90).

INTERPRETATION

Adverse sequelae of adolescent cannabis use are wide ranging and extend into young adulthood. Prevention or delay of cannabis use in adolescence is likely to have broad health and social benefits. Efforts to reform cannabis legislation should be carefully assessed to ensure they reduce adolescent cannabis use and prevent potentially adverse developmental effects.

FUNDING

Australian Government National Health and Medical Research Council.

Social and emotional adjustment following early pregnancy in young Australian women: a comparison of those who terminate, miscarry, or complete pregnancy

PURPOSE

To compare social and emotional adjustment including educational attainment and substance use in women who had a child, pregnancy termination, or miscarriage by young adulthood.

METHODS

Data were from a population-based longitudinal study of the health and well-being of 1,943 young Australians (Victorian Adolescent Health Cohort Study) followed from 15 to 24 years of age. The sample was restricted to female participants and based on pregnancies reported by age 24 years. Analyses were adjusted for early teenage depressive symptoms, cigarette smoking, alcohol use, cannabis use, and parent socioeconomic context.

RESULTS

A total of 208 pregnancies (in 170 women) were reported from a sample of 824 young women by 24 years of age. Compared with those who had never been pregnant, those who had a child had lower tertiary education completion and a higher risk of nicotine dependence; those who terminated a pregnancy were more commonly single and had a higher risk of smoking and alcohol use as well as nicotine and alcohol dependence; and those who had a miscarriage had a higher risk of depressive symptomatology and binge drinking as well as nicotine and cannabis dependence.

CONCLUSIONS

Young women who have been pregnant by their mid-twenties report a range of difficulties in social and emotional adjustment that vary across the different pregnancy outcomes. Broad-based psychosocial health care is essential not only for young women whose pregnancies proceed to live birth, but also for those whose pregnancies end with miscarriage or induced abortion.

The prognosis of common mental disorders in adolescents: a 14-year prospective cohort study

BACKGROUND

Most adults with common mental disorders report their first symptoms before 24 years of age. Although adolescent anxiety and depression are frequent, little clarity exists about which syndromes persist into adulthood or resolve before then. In this report, we aim to describe the patterns and predictors of persistence into adulthood.

METHODS

We recruited a stratified, random sample of 1943 adolescents from 44 secondary schools across the state of Victoria, Australia. Between August, 1992, and January, 2008, we assessed common mental disorder at five points in adolescence and three in young adulthood, commencing at a mean age of 15.5 years and ending at a mean age of 29.1 years. Adolescent disorders were defined on the Revised Clinical Interview Schedule (CIS-R) at five adolescent measurement points, with a primary cutoff score of 12 or higher representing a level at which a family doctor would be concerned. Secondary analyses addressed more severe disorders at a cutoff of 18 or higher.

FINDINGS

236 of 821 (29%; 95% CI 25-32) male participants and 498 of 929 (54%; 51-57) female participants reported high symptoms on the CIS-R (≥12) at least once during adolescence. Almost 60% (434/734) went on to report a further episode as a young adult. However, for adolescents with one episode of less than 6 months duration, just over half had no further common mental health disorder as a young adult. Longer duration of mental health disorders in adolescence was the strongest predictor of clear-cut young adult disorder (odds ratio [OR] for persistent young adult disorder vs none 3.16, 95% CI 1.86-5.37). Girls (2.12, 1.29-3.48) and adolescents with a background of parental separation or divorce (1.62, 1.03-2.53) also had a greater likelihood of having ongoing disorder into young adulthood than did those without such a background. Rates of adolescent onset disorder dropped sharply by the late 20s (0.57, 0.45-0.73), suggesting a further resolution for many patients whose symptoms had persisted into the early 20s.

INTERPRETATION

Episodes of adolescent mental disorder often precede mental disorders in young adults. However, many such disorders, especially when brief in duration, are limited to the teenage years, with further symptom remission common in the late 20s. The resolution of many adolescent disorders gives reason for optimism that interventions that shorten the duration of episodes could prevent much morbidity later in life.

FUNDING

Australia's National Health and Medical Research Council.

Tobacco smoking in adolescence predicts maladaptive coping styles in adulthood

INTRODUCTION

To examine the extent to which cigarette smoking in adolescence is associated with maladaptive versus adaptive coping behaviors in adulthood.

METHOD

The data came from a longitudinal study of New Zealand adolescents followed into adulthood at age 32 years. Using structural equation modeling (SEM), we examined the predictive association between daily smoking of cigarettes and symptoms of tobacco dependence from 18 to 26 years of age and later coping at age 32 years. We included pathways from childhood family disadvantage in addition to both adolescent stress-worry and adult coping in the model.

RESULTS

SEM revealed that cigarette smoking had a small but direct inverse effect on later adaptive coping (-.14) and a direct effect on maladaptive coping (.23) independent of the relationships between adolescent coping and stress-worry and later adult coping.

CONCLUSIONS

The findings are consistent with the hypothesis that tobacco smoking may inhibit the development of self-efficacy or one's ability to act with appropriate coping behaviors in any given situation.

Gene-environment interaction in problematic substance use: interaction between DRD4 and insecure attachments

To investigate the combined effect of an exon III variable number tandem repeat in the dopamine receptor gene (DRD4) and insecure attachment style on risk for tobacco, cannabis and alcohol use problems in young adulthood. It was hypothesized that (1) individuals with 5, 6, 7 or 8 repeats (labelled 7R+) would be at increased risk for problematic drug use, and (2) risk for drug use would be further increased in individuals with 7R+ repeats who also have a history of insecure parent-child attachment relations. Data were drawn from the Victorian Adolescent Health Cohort Study, an eight-wave longitudinal study of adolescent and young adult development. DRD4 genotypes were available for 839 participants. Risk attributable to the combined effects of 7R+ genotype and insecure attachments was evaluated within a sufficient causes framework under the assumptions of additive interaction using a two-by-four table format with a common reference group. 7R+ alleles were associated with higher tobacco, cannabis and alcohol use (binging). Insecure attachments were associated with higher tobacco and cannabis use but lower alcohol use. For tobacco, there was evidence of interaction for anxious but not avoidant attachments. For cannabis, there was evidence of interaction for both anxious and avoidant attachments, although the interaction for anxious attachments was more substantial. There is no evidence of interaction for binge drinking. Results are consistent with a generic reward deficit hypothesis of drug addiction for which the 7R+ disposition may play a role. Interaction between 7R+ alleles and attachment insecurity may intensify risk for problematic tobacco and cannabis use.

Transdifferentiation of cultured human prostate cancer cells to a neuroendocrine cell phenotype in a hormone-depleted medium

Neuroendocrine (NE) cells are enigmatically found in association with human prostate cancers and their numbers are reported to increase in advanced and hormoneresistant tumors. The origin of this cell type and the reason for their appearance in prostate tumors remains unresolved. Previously, Bang et al. (Proc Natl Acad Sci USA 1994;91:5330) reported that dibutyryl adenosine 3',5'-cyclic phosphate (db-cAMP), an agent that upregulates intracellular cAMP, was able to induce a NE cell-like phenotype of cultured human prostate cancer cells, including the androgen-sensitive LNCaP line. Here we report that chronic incubation of LNCaP cells in a medium containing 10% charcoal-stripped fetal bovine serum (CSFBS) likewise induces NE differentiation of these cells. Within 5 days of switching low density cultures of LNCaP cells to this modified medium, the cells growth arrest and acquire an altered morphology with numerous cytoplasmic secretory granules and elongated processes that resemble cultured neurons. This morphology predominates at 10 days with complete transformation seen by 20 days of culture. Electron microscopic analysis of sections of CS-FBS maintained cells showed the presence of abundant dense core secretory granules characteristic of NE cells. Immunohistochemical staining identified the upregulation of the expression of NE markers bombesin, neuron-specific enolase, and S-100 in this modified culture medium. Once established, the NE cell-like phenotype was found to be reversible upon replacement with a medium containing unmodified fetal bovine serum, but not by direct supplementation of CS-FBS medium with dihydrotestosterone (DHT) (I nM). DHT supplementation did, however, suppress the development of the NE cell-like phenotype when it was present at the initiation of exposure to CS-FBS medium. In contrast to db-cAMP treatment, which did not affect prostate specific antigen (PSA) or androgen receptor (AR) expression of LNCaP cells, NE-differentiated LNCaP cells derived in this hormone-deficient medium showed marked downregulation of PSA and AR expression. These in vitro results further support the concept that prostate cancer cells can tranform in vivo to cells with a NE phenotype and suggest that this transformation might be accelerated in patients by certain therapies for prostate cancer.

Stress-sensitive neurosignalling in depression: an integrated network biology approach to candidate gene selection for genetic association analysis

Genetic risk for depressive disorders is poorly understood despite consistent suggestions of a high heritable component. Most genetic studies have focused on risk associated with single variants, a strategy which has so far only yielded small (often non-replicable) risks for depressive disorders. In this paper we argue that more substantial risks are likely to emerge from genetic variants acting in synergy within and across larger neurobiological systems (polygenic risk factors). We show how knowledge of major integrated neurobiological systems provides a robust basis for defining and testing theoretically defensible polygenic risk factors. We do this by describing the architecture of the overall stress response. Maladaptation via impaired stress responsiveness is central to the aetiology of depression and anxiety and provides a framework for a systems biology approach to candidate gene selection. We propose principles for identifying genes and gene networks within the neurosystems involved in the stress response and for defining polygenic risk factors based on the neurobiology of stress-related behaviour. We conclude that knowledge of the neurobiology of the stress response system is likely to play a central role in future efforts to improve genetic prediction of depression and related disorders.

Adolescent depressive symptoms and subsequent pregnancy, pregnancy completion and pregnancy termination in young adulthood: findings from the victorian adolescent health cohort study

STUDY OBJECTIVE

To examine relationships between depressive symptoms in adolescence (14-18 years of age) and becoming pregnant, completing a pregnancy (live birth) and terminating a pregnancy in young adulthood (21-24 years of age).

PARTICIPANTS AND DESIGN

Data from 1000 females were drawn from a larger sample of 1943 young Australians participating in a longitudinal study of adolescent health and development, followed across 8 waves from adolescence (waves 1-6) to young adulthood (waves 7 and 8).

SETTING

Victoria, Australia.

MAIN OUTCOME MEASURES

Pregnancy, pregnancy completion and pregnancy termination between 21-24 years of age.

RESULTS

We observed a twofold increase in the odds of becoming pregnant in those reporting persisting patterns of depressive symptoms during adolescence (2+ waves); however, after staged adjustment for adolescent antisocial behaviour, drug use and socioeconomic disadvantage, there was no evidence of association. Of particular note, and consistent with previous research, adolescent antisocial and drug use behavior were strongly associated with becoming pregnant and pregnancy termination in young adulthood.

CONCLUSIONS

Adolescent antisocial and drug use behavior, not depressive symptoms, independently predict pregnancy outcomes in young adulthood.

Early life stress and child temperament style as predictors of childhood anxiety and depressive symptoms: findings from the longitudinal study of Australian children

Objective. The purpose of this study was to determine whether the relationship between stressful infant environments and later childhood anxiety and depressive symptoms varies as a function of individual differences in temperament style. Methods. Data was drawn from the Longitudinal Study of Australian Children (LSAC). This study examined 3425 infants assessed at three time points, at 1-year, at 2/3 years and at 4/5 years. Temperament was measured using a 12-item version of Toddler Temperament Scale (TTS) and was scored for reactive, avoidant, and impulsive dimensions. Logistic regression was used to model direct relationships and additive interactions between early life stress, temperament, and emotional symptoms at 4 years of age. Analyses were adjusted for socioeconomic status, parental education, and marital status. Results. Stressful family environments experienced in the infant's first year of life (high versus low) and high reactive, avoidant, and impulsive temperament styles directly and independently predicted anxiety and depressive problems in children at 4 years of age. There was no evidence of interaction between temperament and family stress exposure. Conclusions. Both infant temperament and stress exposures are independent and notable predictors of later anxiety and depressive problems in childhood. The risk relationship between stress exposure in infancy and childhood emotion problems did not vary as a function of infant temperament. Implications for preventive intervention and future research directions are discussed.

Association of adolescent symptoms of depression and anxiety with alcohol use disorders in young adulthood: findings from the Victorian Adolescent Health Cohort Study

OBJECTIVE

To examine the association of adolescent depression and anxiety symptoms with alcohol abuse or dependence in young adulthood.

DESIGN, SETTING AND PARTICIPANTS

Cohort study of the health and wellbeing of adolescents and young adults in Victoria, assessed at 8 waves (periods) of data collection, from age 14 to 24 years, between 1992 and 2003. Young people who participated in the cohort study at least once during the six adolescent assessment points (conducted 6 months apart, from age 14 to 17 years), at least once during young adulthood and who were alive at Wave 8 (n = 1758).

MAIN OUTCOME MEASURE

Alcohol abuse or dependence assessed using the alcohol and substance abuse modules of the Composite International Diagnostic Interview at age 24 years.

RESULTS

Adolescents with moderate to high levels of depression and anxiety symptoms (measured by the revised Clinical Interview Schedule) had an increased risk of alcohol abuse or dependence in young adulthood, compared with young adults with low levels of adolescent depression and anxiety symptoms, after adjusting for potential confounding factors. Risk was higher for those with symptoms at more than two adolescent assessment points (odds ratio [OR] 1.9; 95% CI, 1.7-2.0) and for those with symptoms at one or two assessment points (OR 1.3; 95% CI, 1.2-1.4), compared with those with no above-threshold symptoms in adolescence.

CONCLUSIONS

Adolescents with depression and anxiety symptoms are at increased risk for alcohol use disorders into young adulthood. They warrant vigilance from primary care providers in relation to alcohol use well into adulthood.

Development of a multi-dimensional measure of resilience in adolescents: the Adolescent Resilience Questionnaire

Background

The concept of resilience has captured the imagination of researchers and policy makers over the past two decades. However, despite the ever growing body of resilience research, there is a paucity of relevant, comprehensive measurement tools. In this article, the development of a theoretically based, comprehensive multi-dimensional measure of resilience in adolescents is described.

Methods

Extensive literature review and focus groups with young people living with chronic illness informed the conceptual development of scales and items. Two sequential rounds of factor and scale analyses were undertaken to revise the conceptually developed scales using data collected from young people living with a chronic illness and a general population sample.

Results

The revised Adolescent Resilience Questionnaire comprises 93 items and 12 scales measuring resilience factors in the domains of self, family, peer, school and community. All scales have acceptable alpha coefficients. Revised scales closely reflect conceptually developed scales.

Conclusions

It is proposed that, with further psychometric testing, this new measure of resilience will provide researchers and clinicians with a comprehensive and developmentally appropriate instrument to measure a young person's capacity to achieve positive outcomes despite life stressors.