Parental personality and early life ecology: a prospective cohort study from preconception to postpartum.

Personality reliably predicts life outcomes ranging from social and material resources to mental health and interpersonal capacities. However, little is known about the potential intergenerational impact of parent personality prior to offspring conception on family resources and child development across the first thousand days of life. We analysed data from the Victorian Intergenerational Health Cohort Study (665 parents, 1030 infants; est. 1992), a two-generation study with prospective assessment of preconception background factors in parental adolescence, preconception personality traits in young adulthood (agreeableness, conscientiousness, emotional stability, extraversion, and openness), and multiple parental resources and infant characteristics in pregnancy and after the birth of their child. After adjusting for pre-exposure confounders, both maternal and paternal preconception personality traits were associated with numerous parental resources and attributes in pregnancy and postpartum, as well as with infant biobehavioural characteristics. Effect sizes ranged from small to moderate when considering parent personality traits as continuous exposures, and from small to large when considering personality traits as binary exposures. Young adult personality, well before offspring conception, is associated with the perinatal household social and financial context, parental mental health, parenting style and self-efficacy, and temperamental characteristics of offspring. These are pivotal aspects of early life development that ultimately predict a child's long-term health and development.

Factor structure of the Mini-Maternal Behavior Q-Sort and associations with infant attachment: Informing precision in research and intervention.

We examined the factor structure of parental sensitivity to infants as assessed by the Mini-Maternal Behavior Q-Sort (Mini-MBQS), a 25-item short-form of the original 90-item MBQS. We aimed to: (1) identify latent factors of the Mini-MBQS; and (2) validate each factor by testing associations with infant attachment classifications. Data on parent-infant dyads (n = 313; 222 mothers with 281 children, 29 fathers with 32 children) were drawn from a three-generation Australian cohort study. Exploratory Factor Analysis and Exploratory Structural Equation Modelling examined the structure of the Mini-MBQS. Two latent Mini-MBQS factors were identified, requiring 8 of 25 original items: (1) Attention and Responsiveness and (2) Contingency in Interactions. Infants with insecure attachment classifications had parents with lower sensitivity across both factors relative to infants classified secure. In particular, infants with resistant attachment classifications had parents with notably low Contingency in Interactions scores. Infants with disorganised attachment classifications had parents with the lowest relative sensitivity across both factors, and in these dyads Attention and Responsiveness scores were especially low. Results provide an empirically derived factor structure for the Mini-MBQS. Two subscales, each with significant infant attachment associations, may improve precision in clinical intervention and research translation.

Methods and Applications of Social Media Monitoring of Mental Health During Disasters: Scoping Review.

BACKGROUND: With the increasing frequency and magnitude of disasters internationally, there is growing research and clinical interest in the application of social media sites for disaster mental health surveillance. However, important questions remain regarding the extent to which unstructured social media data can be harnessed for clinically meaningful decision-making. OBJECTIVE: This comprehensive scoping review synthesizes interdisciplinary literature with a particular focus on research methods and applications. METHODS: A total of 6 health and computer science databases were searched for studies published before April 20, 2021, resulting in the identification of 47 studies. Included studies were published in peer-reviewed outlets and examined mental health during disasters or crises by using social media data. RESULTS: Applications across 31 mental health issues were identified, which were grouped into the following three broader themes: estimating mental health burden, planning or evaluating interventions and policies, and knowledge discovery. Mental health assessments were completed by primarily using lexical dictionaries and human annotations. The analyses included a range of supervised and unsupervised machine learning, statistical modeling, and qualitative techniques. The overall reporting quality was poor, with key details such as the total number of users and data features often not being reported. Further, biases in sample selection and related limitations in generalizability were often overlooked. CONCLUSIONS: The application of social media monitoring has considerable potential for measuring mental health impacts on populations during disasters. Studies have primarily conceptualized mental health in broad terms, such as distress or negative affect, but greater focus is required on validating mental health assessments. There was little evidence for the clinical integration of social media-based disaster mental health monitoring, such as combining surveillance with social media-based interventions or developing and testing real-world disaster management tools. To address issues with study quality, a structured set of reporting guidelines is recommended to improve the methodological quality, replicability, and clinical relevance of future research on the social media monitoring of mental health during disasters.

Young adult mental health sequelae of eating and body image disturbances in adolescence.

OBJECTIVE: There has been interest in the antecedents and mental health impacts of eating and body image disturbances in adolescence. Less is known about longer-term mental health impacts into young adulthood, as longitudinal studies with data spanning this developmental period are rare. We capitalize on mental health data collected across adolescence and young adulthood from a population-based cohort study that has been following >2000 Australian children and their families from infancy to young adulthood. METHOD: This sample comprised 1,568 participants who completed the Eating Disorder Inventory drive for thinness and bulimic behavior (the severity of binge-purge patterns) subscales, and a modified version of the body dissatisfaction subscale in mid-adolescence (15-16 years), or the Depression Anxiety Stress Scales in young adulthood (19-20, 23-24, and 27-28 years). RESULTS: After adjusting for baseline demographic and prior mental health factors (<13 years of age), all three indices of eating and body image disturbances in adolescence predicted each mental health outcome in young adulthood. Mental health risks associated with adolescent body dissatisfaction and bulimic behavior scores remained stable across young adulthood, with men having more pronounced problems associated with bulimic behavior scores than women. In contrast, mental health risks associated with adolescent drive for thinness scores diminished across this period similarly for men and women. DISCUSSION: Findings suggest that adolescent eating and body image disturbances may have long-term mental health impacts that extend into young adulthood. This underscores the need for early preventative intervention, and longer-term monitoring and support for body image and eating disturbances.

Maternal bonding, negative affect, and infant social-emotional development: A prospective cohort study.

BACKGROUND: Theoretical perspectives and empirical evidence suggest that maternal bonding and negative affect play a role in supporting infant social-emotional development (Branjerdporn et al., 2017; Kingston et al., 2012; O'Donnell et al., 2014; Van den Bergh et al., 2017). However, the complex pathways likely to exist between these constructs remain unclear, with limited research examining the temporal and potentially bi-directional associations between maternal bonding and negative affect across pregnancy and infancy. METHODS: The interrelationships between maternal bonding, negative affect, and infant social-emotional development were examined using multi-wave perinatal data from an Australian cohort study (N = 1,579). Self-reported bonding and negative affect were assessed at each trimester, and 8 weeks and 12 months postpartum. The Bayley-III social-emotional scale was administered at age 12 months. RESULTS: Results revealed strong continuities in bonding and negative affect across pregnancy and postpartum. Small associations (ß = -.10 to -.20) existed between maternal negative affect during pregnancy and poor early bonding. Higher postnatal maternal bonding predicted infant social-emotional development (ß = .17). LIMITATIONS: Limitations include a somewhat advantaged and predominantly Anglo-Saxon sample of families, and the use of self-report measures (though with strong psychometric properties). These limitations should be considered when interpreting the study findings. CONCLUSIONS: Maternal bonding and negative affect are interrelated yet unique constructs, with suggested developmental interplay between mother-to-infant bonding and infant social-affective development.

A comparison of penalised regression methods for informing the selection of predictive markers.

BACKGROUND: Penalised regression methods are a useful atheoretical approach for both developing predictive models and selecting key indicators within an often substantially larger pool of available indicators. In comparison to traditional methods, penalised regression models improve prediction in new data by shrinking the size of coefficients and retaining those with coefficients greater than zero. However, the performance and selection of indicators depends on the specific algorithm implemented. The purpose of this study was to examine the predictive performance and feature (i.e., indicator) selection capability of common penalised logistic regression methods (LASSO, adaptive LASSO, and elastic-net), compared with traditional logistic regression and forward selection methods. DESIGN: Data were drawn from the Australian Temperament Project, a multigenerational longitudinal study established in 1983. The analytic sample consisted of 1,292 (707 women) participants. A total of 102 adolescent psychosocial and contextual indicators were available to predict young adult daily smoking. FINDINGS: Penalised logistic regression methods showed small improvements in predictive performance over logistic regression and forward selection. However, no single penalised logistic regression model outperformed the others. Elastic-net models selected more indicators than either LASSO or adaptive LASSO. Additionally, more regularised models included fewer indicators, yet had comparable predictive performance. Forward selection methods dismissed many indicators identified as important in the penalised logistic regression models. CONCLUSIONS: Although overall predictive accuracy was only marginally better with penalised logistic regression methods, benefits were most clear in their capacity to select a manageable subset of indicators. Preference to competing penalised logistic regression methods may therefore be guided by feature selection capability, and thus interpretative considerations, rather than predictive performance alone.

Social Media Markers to Identify Fathers at Risk of Postpartum Depression: A Machine Learning Approach.

Postpartum depression (PPD) is a significant mental health issue in mothers and fathers alike; yet at-risk fathers often come to the attention of health care professionals late due to low awareness of symptoms and reluctance to seek help. This study aimed to examine whether passive social media markers are effective for identifying fathers at risk of PPD. We collected 67,796 Reddit posts from 365 fathers, spanning a 6-month period around the birth of their child. A list of "at-risk" words was developed in collaboration with a perinatal mental health expert. PPD was assessed by evaluating the change in fathers' use of words indicating depressive symptomatology after childbirth. Predictive models were developed as a series of support vector machine classifiers using behavior, emotion, linguistic style, and discussion topics as features. The performance of these classifiers indicates that fathers at risk of PPD can be predicted from their prepartum data alone. Overall, the best performing model used discussion topic features only with a recall score of 0.82. These findings could assist in the development of support and intervention tools for fathers during the prepartum period, with specific applicability to personalized and preventative support tools for at-risk fathers.

Maternal mental health and infant emotional reactivity: a 20-year two-cohort study of preconception and perinatal exposures.

BACKGROUND: Maternal mental health during pregnancy and postpartum predicts later emotional and behavioural problems in children. Even though most perinatal mental health problems begin before pregnancy, the consequences of preconception maternal mental health for children's early emotional development have not been prospectively studied. METHODS: We used data from two prospective Australian intergenerational cohorts, with 756 women assessed repeatedly for mental health problems before pregnancy between age 13 and 29 years, and during pregnancy and at 1 year postpartum for 1231 subsequent pregnancies. Offspring infant emotional reactivity, an early indicator of differential sensitivity denoting increased risk of emotional problems under adversity, was assessed at 1 year postpartum. RESULTS: Thirty-seven percent of infants born to mothers with persistent preconception mental health problems were categorised as high in emotional reactivity, compared to 23% born to mothers without preconception history (adjusted OR 2.1, 95% CI 1.4-3.1). Ante- and postnatal maternal depressive symptoms were similarly associated with infant emotional reactivity, but these perinatal associations reduced somewhat after adjustment for prior exposure. Causal mediation analysis further showed that 88% of the preconception risk was a direct effect, not mediated by perinatal exposure. CONCLUSIONS: Maternal preconception mental health problems predict infant emotional reactivity, independently of maternal perinatal mental health; while associations between perinatal depressive symptoms and infant reactivity are partially explained by prior exposure. Findings suggest that processes shaping early vulnerability for later mental disorders arise well before conception. There is an emerging case for expanding developmental theories and trialling preventive interventions in the years before pregnancy.

Alcohol and parenthood: An integrative analysis of the effects of transition to parenthood in three Australasian cohorts.

AIMS: To determine the extent to which the transition to parenthood protects against heavy and problematic alcohol consumption in young men and women. DESIGN: Integrated participant-level data analysis from three population-based prospective Australasian cohort studies. SETTING: General community; participants from the Australian Temperament Study, the Christchurch Health and Development Study, and the Victorian Adolescent Health Cohort Study. MEASUREMENTS: Recent binge drinking, alcohol abuse/dependence and number of standard drinks consumed per occasion. FINDINGS: 4015 participants (2151 females; 54%) were assessed on four occasions between ages 21 and 35. Compared to women with children aged <12 months, women who had not transitioned to parenthood were more likely to meet the criteria for alcohol abuse/dependence (fully adjusted risk ratio [RR] 3.5; 95% CI 1.5-7.9) and to report recent binge drinking (RR 3.0; 95% CI 2.1-4.3). The proportion of women meeting the criteria for alcohol abuse/dependence and/or binge drinking increased with the age of participants' youngest child, as did the mean number of standard drinks consumed on each occasion (1.8 if the youngest child was <1 year of age vs. 3.6 for 5+ years of age). Associations between parenthood and male drinking behaviour were considerably weaker. CONCLUSIONS: For most women in their twenties and thirties, parenting a child <1 year of age was associated with reduced alcohol consumption. However, this protective effect diminished after 12 months with drinking levels close to pre-parenthood levels after five years. There was little change in male drinking with the transition to parenthood.

Does adolescent heavier alcohol use predict young adult aggression and delinquency? Parallel analyses from four Australasian cohort studies.

While the association between heavy alcohol consumption and aggression has been well documented, the causal direction of this association, particularly at a population level, is disputed. A number of causal sequences have been proposed. First, that aggression leads to heavy alcohol use. Second, that heavy alcohol use leads to aggression. Third, that the association between alcohol use and aggression is due to confounding by (a) sociodemographic variables or (b) delinquency. We report here data from four Australasian prospective longitudinal studies of adolescents, to assess the temporal sequence of heavy drinking and aggression over the period from adolescence to young adulthood. The four cohort studies provide a total sample of 6,706 persons (Australian Temperament Project, n = 1701; Christchurch Health and Development Study, n = 931; Mater-University of Queensland Study of Pregnancy, n = 2437; Victorian Adolescent Health Cohort Study, n = 1637). We use multinomial logistic regression to determine whether early adolescent aggression predicts subsequent age of onset of heavy episodic drinking (HED), after adjustment for concurrent sociodemographic factors and delinquency. We then consider whether HED predicts subsequent aggression, after adjusting for past aggression, concurrent delinquency, and a range of confounders. There are broadly consistent findings across the four cohort studies. Early aggression strongly predicts subsequent HED. HED predicts later aggression after adjustment for prior aggression and other confounders. Policies that alter population levels of alcohol consumption are likely to impact on levels of aggression in societies where HED linked to aggression is more common.

Machine learning in mental health: a scoping review of methods and applications.

BACKGROUND: This paper aims to synthesise the literature on machine learning (ML) and big data applications for mental health, highlighting current research and applications in practice. METHODS: We employed a scoping review methodology to rapidly map the field of ML in mental health. Eight health and information technology research databases were searched for papers covering this domain. Articles were assessed by two reviewers, and data were extracted on the article's mental health application, ML technique, data type, and study results. Articles were then synthesised via narrative review. RESULTS: Three hundred papers focusing on the application of ML to mental health were identified. Four main application domains emerged in the literature, including: (i) detection and diagnosis; (ii) prognosis, treatment and support; (iii) public health, and; (iv) research and clinical administration. The most common mental health conditions addressed included depression, schizophrenia, and Alzheimer's disease. ML techniques used included support vector machines, decision trees, neural networks, latent Dirichlet allocation, and clustering. CONCLUSIONS: Overall, the application of ML to mental health has demonstrated a range of benefits across the areas of diagnosis, treatment and support, research, and clinical administration. With the majority of studies identified focusing on the detection and diagnosis of mental health conditions, it is evident that there is significant room for the application of ML to other areas of psychology and mental health. The challenges of using ML techniques are discussed, as well as opportunities to improve and advance the field.

Adverse adult consequences of different alcohol use patterns in adolescence: an integrative analysis of data to age 30 years from four Australasian cohorts.

BACKGROUND AND AIMS: Studies have linked adolescent alcohol use with adverse consequences in adulthood, yet it is unclear how strong the associations are and to what extent they may be due to confounding. Our aim was to estimate the strength of association between different patterns of adolescent drinking and longer-term psychosocial harms taking into account individual, family and peer factors. DESIGN: Participant-level data were integrated from four long-running longitudinal studies: Australian Temperament Project, Christchurch Health and Development Study, Mater Hospital and University of Queensland Study of Pregnancy and Victorian Adolescent Health Cohort Study. SETTING: Australia and New Zealand. PARTICIPANTS: Participants were assessed on multiple occasions between ages 13 and 30 years (from 1991 to 2012). Number of participants varied (up to n = 9453) by analysis. MEASUREMENTS: Three patterns of alcohol use (frequent, heavy episodic and problem drinking) were assessed prior to age 17. Thirty outcomes were assessed to age 30 spanning substance use and related problems, antisocial behaviour, sexual risk-taking, accidents, socio-economic functioning, mental health and partner relationships. FINDINGS: After covariate adjustment, weekly drinking prior to age 17 was associated with a two- to threefold increase in the odds of binge drinking [odds ratio (OR) = 2.14; 95% confidence interval (CI) = 1.57-2.90], drink driving (OR = 2.78; 95% CI = 1.84-4.19), alcohol-related problems (OR = 3.04; 95% CI = 1.90-4.84) and alcohol dependence (OR = 3.30; 95% CI = 1.69-6.47) in adulthood. Frequency of drinking accounted for a greater proportion of the rate of most adverse outcomes than the other measures of alcohol use. Associations between frequent, heavy episodic and problem drinking in adolescence and most non-alcohol outcomes were largely explained by shared risk factors for adolescent alcohol use and poor psychosocial functioning. CONCLUSIONS: Frequency of adolescent drinking predicts substance use problems in adulthood as much as, and possibly more than, heavy episodic and problem drinking independent of individual, family and peer predictors of those outcomes.

A prospective study of the substance use and mental health outcomes of young adult former and current cannabis users.

INTRODUCTION AND AIMS: The extent to which young adult former cannabis users fare better than infrequent users is unclear. We investigated the association between cannabis use status at age 23 and substance use and mental health outcomes at age 27. DESIGN AND METHODS: Data were from the 20+ year cohort of the PATH Through Life Study. Lifetime cannabis users (n = 1410) at age 23 were classified as former/occasional/regular users. Multivariable logistic regression was used to estimate the association between cannabis use status at age 23 and six outcomes assessed at age 27. RESULTS: Compared with occasional cannabis users: (i) former users had odds of subsequent tobacco use [odds ratio (OR) = 0.67, 95% confidence interval (CI) 0.52-0.85], illicit drug use (cannabis, OR = 0.22, 95% CI 0.17-0.28; other illicit drugs, OR = 0.29, 95% CI 0.22-0.39) and mental health impairment (OR = 0.71, 95% CI 0.55-0.92) that were 29-78% lower; and (ii) regular users had odds of subsequent frequent alcohol use (OR = 2.34, 95% CI 0.67-1.34), tobacco use (OR = 3.67, 95% CI 2.54-5.30), cannabis use (OR = 11.73, 95% CI 6.81-20.21) and dependence symptoms (OR = 12.60, 95% CI 8.38-18.94), and other illicit drug use (OR = 2.95, 95% CI 2.07-4.21) that were 2-13 times greater. Associations attenuated after covariate adjustment, and most remained significant. DISCUSSION AND CONCLUSIONS: Clear associations exist between cannabis use status in young adulthood and subsequent mental health and substance use. While early intervention remains important to prevent regular cannabis use and the associated harms, experimentation with cannabis use in the years leading into young adulthood may not necessarily determine an immutable pathway to mental health problems and illicit substance use. [Silins E, Swift W, Slade T, Toson B, Rodgers B, Hutchinson DM. A prospective study of the substance use and mental health outcomes of young adult former and current cannabis users. Drug Alcohol Rev 2017;00:000-000].

Adolescent substance use and educational attainment: An integrative data analysis comparing cannabis and alcohol from three Australasian cohorts.

BACKGROUND: The relative contributions of cannabis and alcohol use to educational outcomes are unclear. We examined the extent to which adolescent cannabis or alcohol use predicts educational attainment in emerging adulthood. METHODS: Participant-level data were integrated from three longitudinal studies from Australia and New Zealand (Australian Temperament Project, Christchurch Health and Development Study, and Victorian Adolescent Health Cohort Study). The number of participants varied by analysis (N=2179-3678) and were assessed on multiple occasions between ages 13 and 25. We described the association between frequency of cannabis or alcohol use prior to age 17 and high school non-completion, university non-enrolment, and degree non-attainment by age 25. Two other measures of alcohol use in adolescence were also examined. RESULTS: After covariate adjustment using a propensity score approach, adolescent cannabis use (weekly+) was associated with 1½ to two-fold increases in the odds of high school non-completion (OR=1.60, 95% CI=1.09-2.35), university non-enrolment (OR=1.51, 95% CI=1.06-2.13), and degree non-attainment (OR=1.96, 95% CI=1.36-2.81). In contrast, adjusted associations for all measures of adolescent alcohol use were inconsistent and weaker. Attributable risk estimates indicated adolescent cannabis use accounted for a greater proportion of the overall rate of non-progression with formal education than adolescent alcohol use. CONCLUSIONS: Findings are important to the debate about the relative harms of cannabis and alcohol use. Adolescent cannabis use is a better marker of lower educational attainment than adolescent alcohol use and identifies an important target population 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.

Reduction of adolescent alcohol use through family-school intervention: a randomized trial.

PURPOSE: Two-year longitudinal follow-up data evaluated the behavioral impact of Resilient Families, a universal intervention that aimed to prevent early initiation and frequent and heavy adolescent alcohol use in secondary schools in Melbourne, Australia. METHODS: Of 24 secondary schools (62% of those approached), 12 were randomly assigned to intervention and 12 as controls. Intervention students received a social relationship curriculum; their parents received parent education handbooks and invitations to parent education events outlining strategies to encourage healthy adolescent development and reduce adolescent alcohol misuse. At Wave 1 (2004), students were in Year 7 secondary school (mean age, 12.3 years). Data were imputed for students completing at least two of three annual surveys (N = 2,354). Wave 3 (2006; mean, 14.5 years) main outcome measures for alcohol use were "any," "frequent" (at least monthly), and "heavy" (five or more drinks in a session at least once in the prior fortnight). Multivariate logistic regression assessed intervention exposure effects, adjusting for school classroom clustering and baseline measures. RESULTS: Relative to controls, intervention students showed significant reductions in any lifetime use (adjusted odds ratio [AOR], .78; 95% confidence interval [CI], .62-.97), and reduced progression to frequent (AOR, .69; CI, .56-.86) and heavy use (AOR, .75; CI, .60-.94). CONCLUSIONS: Randomized assignment to Resilient Families was associated with a significant reduction in adolescent alcohol use among families volunteering for the evaluation. Family-school-based interventions appear promising as a strategy to contribute to population reductions in currently high rates of adolescent alcohol misuse.

Adolescent girls' friendship networks, body dissatisfaction, and disordered eating: examining selection and socialization processes.

Previous research has shown that adolescent girls tend to resemble their friends in their level of body dissatisfaction and disordered eating. However, no studies to date have attempted to disentangle the underlying peer selection and socialization processes that may explain this homophily. The current study used longitudinal stochastic actor-based modeling to simultaneously examine these two processes in a large community sample of adolescent girls (N = 1,197) from nine Australian girls' high schools. Friendship nominations and measures of body dissatisfaction, dieting and bulimic behaviors were collected across three annual waves. Results indicated that selection rather than socialization effects contributed to similarity within friendship groups when both processes were examined simultaneously. Specifically, girls tended to select friends who were similar to themselves in terms of body dissatisfaction and bulimic behaviors, but dissimilar in terms of dieting. Network and individual attribute variables also emerged as significant in explaining changes in adolescents' friendships and behaviors. As well as having important clinical implications, the findings point to the importance of controlling for friendship selection when examining the role of peers in adolescent body image and eating problems.

A longitudinal investigation of perceived friend influence on adolescent girls' body dissatisfaction and disordered eating.

Although major etiological models highlight the importance of friends in the development of adolescent body image and eating problems, longitudinal research that comprehensively investigates possible direct and mediational relationships between these variables is lacking. Thus, this study aimed to examine prospective interrelationships between perceived friend influence, body dissatisfaction, and disordered eating in early adolescent girls, and whether these relationships differed across levels of body mass. A large Australian community sample of female high school students (N = 1,094; Time 1 M age = 12.3 years) completed a battery of self-report questionnaires assessing perceived friend influence, body dissatisfaction, and disordered eating at 3 yearly intervals. Height and weight were also measured at each time point. Structural equation modeling was used to investigate two separate models, in which Time 2 body dissatisfaction was hypothesized to mediate the relationship between Time 1 perceived friend influence and Time 3 dieting and bulimic behaviors. No significant direct or indirect pathways were found between friend influence and disordered eating. Unexpectedly, however, body dissatisfaction was found to prospectively predict girls' perception of friend influence. These findings were remarkably similar in both healthy and overweight girls. The findings suggest that friends may be more influential for those adolescents who have higher levels of body image concern, rather than contributing directly to the development of body dissatisfaction. The peer environment represents an important consideration in adolescent prevention and intervention programs.

Cannabis and depression: an integrative data analysis of four Australasian cohorts.

BACKGROUND: This study presents an integrative data analysis of the association between frequency of cannabis use and severity of depressive symptoms using data from four Australasian cohort studies. The integrated data comprised observations on over 6900 individuals studied on up to seven occasions between adolescence and mature adulthood. METHODS: Repeated measures data on frequency of cannabis use (not used/