Incidence and course of adolescent deliberate self-harm in Victoria, Australia, and Washington State

PURPOSE: There have been few longitudinal studies of deliberate self-harm (DSH) in adolescents. This cross-national longitudinal study outlines risk and protective factors for DSH incidence and persistence. METHODS: Seventh and ninth grade students (average ages 13 and 15 years) were recruited as state-representative cohorts, surveyed, and then followed up 12 months later (N = 3,876), using the same methods in Washington State and Victoria, Australia. The retention rate was 99% in both states at follow-up. A range of risk and protective factors for DSH were examined using multivariate analyses. RESULTS: The prevalence of DSH in the past year was 1.53% in Grade 7 and .91% in Grade 9 for males and 4.12% and 1.34% for Grade 7 and Grade 9 females, respectively, with similar rates across states. In multivariate analyses, incident DSH was lower in Washington State (odds ratio [OR] = .67; 95% confidence interval [CI] = .45-1.00) relative to Victoria 12 months later. Risk factors for incident DSH included being female (OR = 1.93; CI = 1.35-2.76), high depressive symptoms (OR = 3.52; CI = 2.37-5.21), antisocial behavior (OR = 2.42; CI = 1.46-4.00), and lifetime (OR = 1.85; CI = 1.11-3.08) and past month (OR = 2.70; CI = 1.57-4.64) alcohol use relative to never using alcohol. CONCLUSIONS: Much self-harm in adolescents resolves over the course of 12 months. Young people who self-harm have high rates of other health risk behaviors associated with family and peer risks that may all be targets for preventive intervention.

The effect of school suspensions and arrests on subsequent adolescent antisocial behavior in Australia and the United States

Purpose: To examine the effect of school suspensions and arrests (i.e., being taken into police custody) on subsequent adolescent antisocial behavior such as violence and crime, after controlling for established risk and protective factors in Victoria, Australia and Washington State, United States (U.S.). Methods: This article reports on analyses of two points of data collected 1 year apart within a cross-national longitudinal study of the development of antisocial behavior, substance use, and related behaviors in approximately 4000 students aged 12 to 16 years in Victoria, Australia and Washington State, U.S. Students completed a modified version of the Communities That Care self-report survey of behavior, as well as risk and protective factors across five domains (individual, family, peer, school, and community). Multivariate logistic regression analyses investigate the effect of school suspensions and arrests on subsequent antisocial behavior, holding constant individual, family, peer, school, and community level influences such as being female, student belief in the moral order, emotional control, and attachment to mother. Results: At the first assessment, school suspensions and arrests were more commonly reported in Washington, and school suspensions significantly increased the likelihood of antisocial behavior 12 months later, after holding constant established risk and protective factors (adjusted odds ratio [OR] 1.5, 95% confidence interval [CI] 1.1–2.1, _p < .05). Predictors of antisocial behavior spanned risk and protective factors across five individual and ecological areas of risk. Risk factors in this study were pre-existing antisocial behavior (OR 3.6, CI 2.7–4.7, _p < .001), association with antisocial peers (OR 1.8, CI 1.4–2.4, _p < .001), academic failure (OR 1.3, CI 1.1–1.5, _p < .01), and perceived availability of drugs in the community (OR 1.3, CI 1.1–1.5, _p < .001). Protective factors included being female (OR 0.7, CI 0.5–0.9, _p < .01), student belief in the moral order (OR 0.8, CI 0.6–1.0, p < .05), student emotional control (OR 0.7, CI 0.6–0.8, _p < .001), and attachment to mother (OR 0.8, CI 0.7–1.0, _p < .05). Conclusions:  School suspensions may increase the likelihood of future antisocial behavior. Further research is required to both replicate this finding and establish the mechanisms by which school suspensions exert their effects.

Longitudinal examination of physical and relational aggression as precursors to later problem behaviors in adolescents

Research has addressed the consequences of being a victim of physical and relational aggression but less so the consequences of being an aggressor during adolescence. Consequently, relatively little is known about the extent to which aggression in early adolescence increases the risk of later aggression and other psychosocial problems. This study involves a representative sample of seventh- and ninth-grade students from Washington State ( N = 1,942). Students were surveyed on recruitment and then again 1 and 2 years later to learn about ongoing behavior problems, substance use, depression, and self-harm behaviors. Surveys also included measures of several hypothesized promotive factors: attachment to family, school commitment, and academic achievement. Findings suggest that being physically and/or relationally aggressive in grades 7 to 9 increases the risk of aggression and possibly other problem behaviors after accounting for age, gender, race, and a prior measure of each outcome. Independent promotive effects were observed in most analyses, although family attachment appeared a less robust predictor overall. Implications for prevention include acting on the behavior itself and enhancing promotive influences to lessen the risk of agression and other related problems.

Modifiable determinants of youth violence in Australia and the United States : a longitudinal study

Youth violence is a global problem. Few studies have examined whrther the prevalence or predictors of youth violence are similar in comparable Western countries like Australia and the United States (US). In the current article, analyses are conducted using two waves of data collected as part of a longitudinal study of adolescent development in approximately 4,000 students aged 12 to 16 years in Victoria, Australia and Washington State, US. Students completed a self-report survey of problem behaviours including violent behaviour, as well as risk and protective factors across five domains (individual, family, peer, school, community). Compared to Washington State, rates of attacking or beating another over the past 12 months were lower in Victoria for females in the first survey and higher for Victorian males in the follow-up survey. Preliminary analyses did not show state-specific predictors of violent behaviour. In the final multivariate analyses of the combined Washington State and Victorian samples, protective factors were being female and student emotion control. Risk factors were prior violent behaviour, family conflict, association with violent peers, community disorganisation, community norms favourable to drug use, school suspensions and arrests. Given the similarity of influential factors in North America and Australia, application of US early intervention and prevention programs may be warranted, with some tailoring to the Australian context.

Saw palmetto supplement use and prostate cancer risk

Saw palmetto is an herb used to treat the symptoms of benign prostatic hyperplasia. In vitro studies have found that saw palmetto inhibits growth of prostatic cancer cells and may induce apoptosis. To evaluate whether saw palmetto supplements are associated with a reduced risk of prostate cancer, we conducted a prospective cohort study of 35,171 men aged 50-76 yr in western Washington state. Subjects completed questionnaires between 2000 and 2002 on frequency of use of saw palmetto supplements and saw palmetto-containing multivitamins over the previous 10 yr in addition to other information on supplement intake, medical history, and demographics. Men were followed through December 2003 (mean of 2.3 yr of follow-up) via the western Washington Surveillance, Epidemiology, and End Results cancer registry, during which time 580 developed prostate cancer. Ten percent of the cohort used saw palmetto at least once per week for a year in the 10 yr before baseline. No association was found between this level of use of saw palmetto and risk of prostate cancer development [hazard ratio (HR) = 0.95; 95% confidence interval = 0.74-1.23] or with increasing frequency or duration of use. In this free-living population, use of commercial saw palmetto, which varies widely in dose and constituent ratios, was not associated with prostate cancer risk.

Alcohol use and related harms in school students in the USA and Australia

Recognizing there have been few methodologically rigorous cross-national studies of youth alcohol and drug behaviour, state student samples were compared in Australia and the USA. Sampling methods were matched to recruit two independent, state-representative, cross-sectional samples of students in Grades 5, 7 and 9 in Washington State, USA, (n = 2866) and Victoria, Australia (n = 2864) in 2002. Of Washington students in Grade 5 (age 11), 10.3% (95% CI 7.2–14.7) of boys and 5.2% (95% CI 3.4–7.9) of girls reported alcohol use in the past year. Prevalence rates were markedly higher in Victoria (34.2%, 95% CI 28.8–40.1 boys; 21.0%, 95% CI 17.1–25.5 girls). Relative to Washington, the students in Victoria demonstrated a two to three times increased likelihood of reporting substance use (either alcohol, tobacco or illicit drug use), and by Grade 9, experiences of loss-of-control of alcohol use, binge drinking (frequent episodes of five or more alcoholic drinks), and injuries related to alcohol were two to four times higher. The high rates of early age alcohol use in Victoria were associated with frequent, heavy and harmful alcohol use and higher overall exposure to alcohol or other drug use. These findings reveal considerable variation in international rates of both adolescent alcohol misuse and co-occurring drug use and suggest the need for cross-national research to identify policies and practices that contribute to the lower rate of adolescent alcohol and drug use observed in the USA in this study.

Pubertal stage and the prevalence of violence and social/relational aggression

OBJECTIVE We examined associations between pubertal stage and violent adolescent behavior and social/relational aggression.

METHODS The International Youth Development Study comprises statewide representative student samples in grades 5, 7, and 9 (N = 5769) in Washington State and Victoria, Australia, drawn as a 2-stage cluster sample in each state. We used a school-administered, self-report student survey to measure previous-year violent behavior (ie, attacking or beating up another person) and social/relational aggression (excluding peers from the group, threatening to spread lies or rumors), as well as risk and protective factors and pubertal development. Cross-sectional data were analyzed.

RESULTS Compared with early puberty, the odds of violent behavior were approximately threefold higher in midpuberty (odds ratio [OR]: 2.87 [95% confidence interval (CI): 1.81–4.55]) and late puberty (OR: 3.79 [95% CI: 2.25–6.39]) after adjustment for demographic factors. For social/relational aggression, there were weaker overall associations after adjustment, but these associations included an interaction between pubertal stage and age, and stronger associations with pubertal stage at younger age were shown (P = .003; midpuberty OR: 1.78 [95% CI: 1.20–2.63]; late puberty OR: 3.00 [95% CI: 1.95–4.63]). Associations between pubertal stage and violent behavior and social/relational aggression remained after the inclusion of social contextual mediators in the analyses.

CONCLUSIONS Pubertal stage was associated with higher rates of violent behavior and social/relational aggression, with the latter association seen only at younger ages. Puberty is an important phase at which to implement prevention programs to reduce adolescent violent and antisocial behaviors.

Influence of family factors and supervised alcohol use on adolescent alcohol use and harms : similarities between youth in different alcohol policy contexts

Objective: Harm-minimization policies suggest that alcohol use is a part of normal adolescent development and that parents should supervise their children's use to encourage responsible drinking. Zero-tolerance policies suggest that all underage alcohol use should be discouraged. This article compared hypotheses derived from harm-minimization and zero-tolerance policies regarding the influence of family context and supervised drinking on adolescent alcohol use and related harms among adolescents in Washington State, USA, and Victoria, Australia. two states that have respectively adopted zero-tolerance and harm-minimization policies.

Method: Representative samples of seventh-grade students (N = 1,945:989 females) were recruited from schools in each state. Students completed comprehensive questionnaires on alcohol use, related problem behaviors, and risk and protective factors annually from 2002 to 2004 when they were in ninth grade.

Results: Relationships between family context and alcohol use and harmful use were very similar in both states. Adult-supervised settings for alcohol use were associated with higher levels of harmful alcohol consequences. Adult-supervised alcohol use mediated the links between favorable parental attitudes to alcohol use and ninth-grade alcohol use for students in both states.

Conclusions: Despite policy differences in the two states, relationships between family context variables and alcohol use and harmful use are remarkably similar. Adult-supervised settings for alcohol use resulted in higher levels of harmful alcohol consequences, contrary to predictions derived from harm-minimization policy. Findings challenge the harm-minimization position that supervised alcohol use or early-age alcohol use will reduce the development of adolescent alcohol problems.

Early age alcohol use and later alcohol problems in adolescents : individual and peer mediators in a bi-national study

This paper examines whether there is cross-national similarity in the longitudinal relationship between early age alcohol use and adolescent alcohol problems. Potential mechanisms underlying this relationship also are examined, testing adolescent alcohol use, low self-regulation, and peer deviance as possible mediators. Students (N = 1,945) participating in the International Youth Development Study, a longitudinal panel survey study, responded to questions on alcohol use and influencing factors, and were followed annually over a 3-year period from 2002 to 2004 (98% retention rate). State-representative, community student samples were recruited in grade 7 in Washington State, United States (US, n = 961, 78% of those eligible; Mage = 13.09, SD = .44) and Victoria, Australia (n = 984, 76% of those eligible; Mage = 12.93, SD = .41). Analyses were conducted using multiple-group structural equation modeling. In both states, early age alcohol use (age 13) had a small but statistically significant association with subsequent alcohol problems (age 15). Overall, there was little evidence for mediation of early alcohol effects. Low self-regulation prospectively predicted peer deviance, alcohol use, and alcohol problems in both states. Peer deviance was more positively related to alcohol use and low self-regulation among students in Victoria compared to students in Washington State. The small but persistent association of early age alcohol use with alcohol problems across both samples is consistent with efforts to delay alcohol initiation to help prevent problematic alcohol use. Self-regulation was an important influence, supporting the need to further investigate the developmental contribution of neurobehavioral disinhibition.

Multiple identification and risks : examination of peer factors across multiracial and single-race youth

Multiracial youth are thought to be more vulnerable to peer-related risk factors than are single-race youth. However, there have been surprisingly few well-designed studies on this topic. This study empirically investigated the extent to which multiracial youth are at higher risk for peer influenced problem behavior. Data are from a representative and longitudinal sample of youth from Washington State (N = 1,760, mean age = 14.13, 50.9% girls). Of those in the sample, 225 youth self-identified as multiracial (12.8%), 1,259 as White (71.5%), 152 as Latino (8.6%), and 124 as Asian American (7.1%). Results show that multiracial youth have higher rates of violence and alcohol use than Whites and more marijuana use than Asian Americans. Higher levels of socioeconomic disadvantage and single-parent family status partly explained the higher rates of problem behaviors among multiracial youth. Peer risk factors of substance-using or antisocial friends were higher for multiracial youth than Whites, even after socioeconomic variables were accounted for, demonstrating a higher rate of peer risks among multiracial youth. The number of substance-using friends was the most consistently significant correlate and predictor of problems and was highest among multiracial youth. However, interaction tests did not provide consistent evidence of a stronger influence of peer risks among multiracial youth. Findings underscore the importance of a differentiated understanding of vulnerability in order to better target prevention and intervention efforts as well as the need for further research that can help identify and explain the unique experiences and vulnerabilities of multiracial youth.

Individual variability in Diel Vertical migration of a marine copepod : why some individuals remain at depth when others migrate

The diel vertical migration (DVM) of the copepod Metridia pacifica was examined in Dabob Bay (47°45.05′N, 122°49.71′W), a fjord in Washington state. Although the population showed deep daytime residence (75-175 m), a proportion of the population was found in the surface waters at night. For individuals that migrated to the surface, the mean size of the oil sac was much smaller than those that remained at depth (mean lengths of oil sac 0.25 mm for individuals collected between 0 and 25 m at night, compared with 0.43 mm for individuals from between 125 and 175 m). Similarly, the C : N ratio was lower for animals collected from near the surface, indicative of their lower lipid reserves. These results suggest that individual variability in DVM was influenced by body condition, with those animals with larger lipid stores not needing to risk coming to the surface to feed at night.

Adolescent predictors and environmental correlates of young adult alcohol use problems

To examine the rates of young adult alcohol and drug use and alcohol problems, adolescent predictors of young adult alcohol problems and correlations with young adult social, work and recreational environments.

Social norms in the development of adolescent substance use: a longitudinal analysis of the International Youth Development Study.

Identifying specific aspects of peer social norms that influence adolescent substance use may assist international prevention efforts. This study examines two aggregated measures of social norms in the school setting and their predictive association with substance (alcohol, tobacco and marijuana) use 2 years later in a large cross-national population-based cohort of adolescents. The primary hypothesis is that in Grade 7 both "injunctive" school norms (where students associate substance use with "coolness") and "descriptive" norms (where student substance use is common) will predict Grade 9 substance use. Data come from the International Youth Development Study, including 2,248 students (51.2% female) in the US and Australia attending 121 schools in Grade 7. Independent variables included injunctive norms (aggregating measures of school-wide coolness ratings of each substance use) and descriptive norms (aggregating the prevalence of school substance use) in Grade 7. Dependent variables included binge drinking and current use of alcohol, tobacco and marijuana in Grade 9. Associations between each type of school-wide social norm and substance use behaviors in Grade 9 were tested using multilevel logistic regression, adjusting for covariates. In unadjusted models, both injunctive and descriptive norms each significantly predicted subsequent substance use. In fully adjusted models, injunctive norms were no longer significantly associated with Grade 9 use, but descriptive norms remained significantly associated with tobacco and marijuana use in the expected direction. The findings identify descriptive social norms in the school context as a particularly important area to address in adolescent substance use prevention efforts.

A longitudinal study of the association of adolescent polydrug use, alcohol use and high school non-completion

AIMS: Failure to complete high school predicts substantial economic and social disadvantage in adult life. The aim of this study was to determine the longitudinal association of mid-adolescent polydrug use and high school non-completion, relative to other drug use profiles. DESIGN: A longitudinal analysis of the relationship between polydrug use in three cohorts at grade 9 (age 14-15 years) and school non-completion (reported post-high school). SETTING: A State-representative sample of students across Victoria, Australia. PARTICIPANTS: A total of 2287 secondary school students from 152 high schools. The retention rate was 85%. MEASUREMENTS: The primary outcome was non-completion of grade 12 (assessed at age 19-23 years). At grade 9, predictors included 30-day use of eight drugs, school commitment, academic failure and peer drug use. Other controls included socio-economic status, family relationship quality, depressive symptoms, gender, age and cohort. FINDINGS: Three distinct classes of drug use were identified-no drug use (31.7%), mainly alcohol use (61.8%) and polydrug use (6.5%). Polydrug users were characterized by high rates of alcohol, tobacco and cannabis use. In the full model, mainly alcohol users and polydrug users were less likely to complete school than non-drug users [odds ratio (OR) = 1.54, 95% confidence interval (CI) = 1.17-2.03) and OR = 2.51, 95% CI = 1.45-4.33), respectively, P < 0.001]. These effects were independent of school commitment, academic failure, peer drug use and other controls. CONCLUSIONS: Mid-adolescent polydrug use in Australia predicts subsequent school non-completion after accounting for a range of potential confounding factors. Adolescents who mainly consume alcohol are also at elevated risk of school non-completion.