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(2018)ThesisSubstance use disorders (SUDs) and depression are highly comorbid conditions. This thesis aims to improve understanding of the gender-specific relationship between these disorders by examining outcomes associated with their comorbidity and processes underlying their co-occurrence and persistence. Studies One to Three used data from an 11-year study of heroin dependent individuals (N=615). Study One provided long-term data on depression among this cohort. Current depression prevalence declined from 23.8% to 8.2% over the first three years, but approximated baseline levels at 11-years (20.9%). Over half of those with depression at baseline experienced recurrent depression. Current and recurrent depression were associated with poorer substance use outcomes at 11-years. Study Two examined the potentially reciprocal impact of substance use severity and depressive symptoms on one another over time. A strong concurrent relationship was found between substance use and depressive symptoms at multiple assessments over three years but neither symptom set predicted the other longitudinally, suggesting that their concurrent association may result from shared risk factors. Studies Three and Four examined whether repetitive negative thinking (RNT) is a shared risk factor for substance use, depression and their comorbidity. Study Three focused on rumination, examining its “brooding” and “reflection” subtypes. Higher levels of ruminative brooding were cross-sectionally associated with depression, substance use severity, and comorbid depression and heroin dependence. Ruminative reflection was unrelated to outcomes. Using a treatment-seeking sample experiencing SUD and comorbid depression (n=67), Study Four examined whether different types of RNT predict the persistence of depression and SUD over 3 months. Rumination subtypes were not associated with the persistence of disorders. Higher levels of perseverative thinking predicted the persistence of SUD. Males and females exhibited more similarities than differences in the relationship between substance use and depression, and the effects of RNT. Further research on gender differences is encouraged given the limited research in the broader literature. The high prevalence and recurrence of depression, and its consistent association with greater concurrent substance use severity, highlight the importance of monitoring and addressing depression among substance users. Findings on RNT demonstrate its potential utility as a target for transdiagnostic prevention and treatment interventions for comorbidity.
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(2018)ThesisBullying among school-aged children is a common issue worldwide and is associated with significant concurrent and prospective emotional and behavioural problems. To date, bullying research and intervention has been limited in several areas, including: the predominance of a narrow focus on bullying types and associated problems; few prospective studies; limited effectiveness of universal interventions for adolescent bullying; and a lack of targeted interventions for bullying and associated harms. This thesis aims to address these gaps through an examination of a cohort of Australian adolescents. Specifically, this thesis aims to: 1) Compare concurrent internalising and externalising problems and suicidal ideation among bullies, victims and bully-victims; 2) Examine concurrent and prospective associations between bullying (victimisation and/or perpetration) and substance use; 3) Examine prospective associations between personality types and bullying (victimisation and perpetration); and 4) Assess an innovative personality-focused approach to bullying intervention (for bullies and victims). This thesis provides novel and important contributions to the bullying literature. Firstly, there was a high prevalence of internalising and externalising problems and suicidal ideation among adolescents involved in all forms of bullying, and particularly among bully-victims. Secondly, there was evidence of a prospective relationship between bully-victim status and risky drinking and cannabis use. Thirdly, personality dimensions predicted both bullying victimisation and bullying perpetration. Finally, a personality-targeted intervention reduced further victimisation, suicidality and internalising problems among victims, and suicidality and externalising problems among bullies. Clinical and research implications are discussed, including: the need for improved understanding of, and addressing the overlap between, bullying victimisation and perpetration and the associated problems; the importance of screening adolescents involved in bullying for externalising problems, internalising problems, and suicidal ideation; a need for further exploration of the role of personality in bullying; and the need for more feasible school-based bullying intervention. Overall, it is clear from this thesis that targeted intervention for adolescents involved in bullying is of vital importance in tackling adolescent bullying and associated harms.
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(2016)ThesisBackground Mother-infant relationship quality in the first year of life has important implications for offspring development through the life course. The emotional bond that a mother feels towards her baby is critical to offspring social, emotional and cognitive development (Bornstein, 2014). Likewise, the capacity for a mother and her infant to share an emotional connection and enjoy a mutually fulfilling and healthy relationship, otherwise known as emotional availability (EA), is critical to establishing positive parent-child relationships (Biringen & Easterbrooks, 2012). Despite an emerging literature on the importance of bonding and EA, little is known about the predictors of the mother’s felt bond to her offspring across pregnancy and the postnatal period as well as emotional availability at infant age 12-months. Even less is known about the predictors of the relationship between partners and their infants. There are a range of factors theorised to promote bonding and EA in infancy including healthy parent-infant bonding during pregnancy and parent wellbeing (i.e., good mental health and low-risk substance use); yet these factors have not been comprehensively assessed in both mothers and their partners across the first year of life. Aims Four empirical studies sought to examine: (1) maternal bonding to offspring across the pregnancy and postnatal period, and to examine a broad range of sociodemographic and psychosocial predictors of the maternal-offspring bond; (2) the extent to which mother-fetal bonding, substance use and mental health through pregnancy predicted postnatal mother-infant bonding at 8-weeks; (3) the extent to which postnatal bonding, maternal mental ill-health and substance use at infant age 8-weeks predicted mother-infant bonding and mother EA at 12-months of age; and, (4) the role of mother and partner bonding, mental health and substance use at 8-weeks post-birth on mother and partner-infant EA at 12-months infant age, accounting for the correlated dyadic influence. Methods Using a sample of pregnant women participating in an Australian pregnancy cohort study of perinatal health and development, participants completed maternal and paternal bonding, mental health and substance use questionnaires at each trimester (one, two and three), 8-weeks and 12-months postnatal. Data was collected on a range of sociodemographic and psychosocial factors. The EA Scales were used to code the quality of interactions between mother-infant and partner-infant dyads during a 20-minute free play observational video recorded at 12-months infant age. Results Maternal-fetal bonding increased in quality and intensity across the pregnancy period with a plateauing of bonding representations towards the end of pregnancy. Bonding between late pregnancy and the early postnatal period remained relatively stable. Maternal-fetal bonding was the strongest predictor of maternal bonding in the postnatal period, both at 8-weeks and 12-months. Mental health and substance use also predicted both maternal and paternal relationship quality, as indicated by bonding and EA measures. Tobacco use for both mothers and partners was negatively associated with EA at 12-months. Conclusion The results of this thesis show that early bonding to the fetus was not only important in laying the foundation for mother-infant bonding in the early postnatal period, but also later in the postnatal period. Moreover, both maternal mental ill-health and substance use appeared to play a small yet significant role in predicting later bonding. However, it was notable that substance use occurred only infrequently in the sample and that substance abuse/dependence were not reported in this sample. These results highlight the importance of supporting the development of a healthy bond between a mother and her fetus during pregnancy and in the early postnatal period. The results also suggest that interventions could be targeted towards parents struggling with symptoms of depression and/or substance use during pregnancy and postnatal. Interventions aimed at emotional regulation and EA promotion for young parents with a history of depression and substance use might also be helpful in strengthening the mother/partner-child relationship. There is a need for further longitudinal research continuing into the toddler and preschool years, including continued assessment of partners and the important role they play. Targeted interventions aimed at enhancing bonding have the potential to strengthen parent-infant relationships through the first year of life.
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(2008)ThesisSuicide attempts and opioid dependence are important clinical issues, as both are associated with a high degree of psychiatric morbidity and elevated risk of mortality. Research has identified a number of risk factors for suicide attempts among the general population, and to a lesser extent, among heroin users. Due to a lack of case-control studies, however, it is still not known to what extent opioid dependence per se is a risk factor for suicide attempts. This thesis comprised the first study to directly examine whether opioid dependence is a unique risk factor of suicide attempts. This thesis examined suicide attempts, associated risk factors, and related comorbidity among an opioid-dependent case group and a non-opioid-dependent control group. A structured interview was used to collect data from 726 opioid-dependent cases and 399 non-opioid-dependent controls. This thesis identified a number of important findings. Firstly, although opioid-dependent individuals were more likely to report lifetime suicide attempts compared to controls, the risk factors were largely the same for both groups. It appeared that opioid-dependent individuals were characterised by a higher likelihood of the same risk factors for suicide attempts, rather than having different risks. Cases appeared to be at increased risk of suicide attempts because of increased levels of multiple risk factors. Secondly, borderline personality disorder (BPD) and impulsivity were identified as important risk markers for suicidal behaviour, especially among opioid-dependent individuals. The study concluded that the treatment of BPD should be prioritised among this group. Third, self-mutilation was identified as a clinically significant problem in its own right, however, when combined with a history of attempted suicide, the psychological dysfunction observed was found to be very high. Fourth, non-fatal opioid overdose and suicide attempts were found to be distinct behaviours. The risk factors for each were completely different. While drug-related risks were associated with non-fatal overdose, the risk markers for suicide attempts were related to the presence of psychological disorders. This thesis has highlighted important areas of concern for clinical interventions as well as for future research to explore. Considering this is the first study of its kind, future research should focus on its replication.
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(2011)ThesisClose investigation of cannabis use in young adulthood is warranted as there is a prolongation of the period of risk of initiation beyond adolescence. Few studies have investigated the factors associated with patterns of cannabis use in young adulthood after the peak age of onset. This is an important period to investigate as risk factors for cannabis use can emerge throughout the life-course and the opportunity to influence adverse developmental pathways can be extended beyond childhood and adolescence. This thesis examined the correlates, predictors and consequences of patterns of cannabis use in young adulthood, using two successive waves of data from 2,404 young adults enrolled in the PATH Through Life Project, an Australian longitudinal survey of the influence of lifestyle and social factors on health. The thesis demonstrates that, although cannabis use tends to decline in young adulthood, a notable proportion of young adults remain involved with the drug. Relapse to cannabis use in young adulthood is not uncommon among former users. Those who first use cannabis in young adulthood generally do not continue or progress to intensive use. A range of factors spanning numerous domains are correlated with cannabis use in young adulthood. A close connection exists between licit drugs and cannabis use. Early cannabis use and the pattern of cannabis use in young adulthood are particularly important predictors of subsequent use of the drug. Regular cannabis use in young adulthood increases the likelihood of later psychosocial and substance use problems including educational underachievement, heavy drinking, tobacco use, cannabis dependence and other illicit drug use. In contrast, ceasing cannabis use in young adulthood has considerable benefits in terms of reducing several potential harms (mental health problems, cannabis dependence, other illicit drug use) and increasing adult role participation. Risk and protective factors associated with variability and stability of cannabis use in young adulthood include gender, first use at an early age, dimensions of personality, religiosity, conflict and hostility in friendships and an environment of licit drug use. The results provide a clearer picture of the patterns of cannabis use in young adulthood and the factors that contribute to explaining them. The findings of this thesis make an important contribution to the development of prevention and intervention strategies for young adults by drawing attention to specific areas of vulnerability and resistance.
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(2016)ThesisThe study in this dissertation compared the effectiveness and cost-effectiveness of two dominant heroin dependence treatment approaches: center-based compulsory rehabilitation (CCT) and community-based voluntary methadone treatment (MMT) in Hai Phong City, Vietnam. CCT centers are institutions in which people who use drugs are confined for two years. MMT has been internationally recognized as an efficacious treatment for heroin dependence and was introduced in Vietnam in 2008. The design was a pragmatic, combined retrospective and prospective, non-randomized cohort over three years (with data at five time-points). The study was conducted between 2012 and 2014, involving 208 CCT participants (of which 80% were followed up) and 384 MMT participants (of which 78% were followed up) with heroin dependence. Mixed effects regression models were used to analyze the effectiveness data and non-parametric bootstrapping methods were used to estimate cost-effectiveness. The study found greater effectiveness of MMT treatment for four outcome measures (‘heroin use’ (β=4.03, SE=0.16, p<.0001), ‘drug-free days (in the preceding 30 days)’ (β=17.51, SE=0.49, p<.0001), ‘BBV risk behaviors’ (β=0.41, SE=0.09, p<.0001), equivalent to OR=1.51, and ‘monthly drug spending’ (β=-4,863,100, SE=262,400, p<.0001)). The analyses did not support the hypothesis that MMT was associated with greater effectiveness pertaining to two outcome variables ‘illegal behaviors’ (β=0.19, SE=0.11, p=0.09) and ‘overdose’ (β=0.03, SE=0.21, p=0.62). Over three years, MMT cost on average VND85.73 million less than CCT (95% CI: -VND76.88 million, -VND94.59 million). On average, a MMT participant had 344.20 more drug-free days compared to a CCT participant and the difference was statistically significant (p<0.001). The results suggested that MMT dominated CCT (both less expensive and more effective). The study findings have been and will continue to be used for drug policy advocacy in Vietnam. Scientific evidence is only one type of information available to politicians. Information, including scientific and other types of information, has to compete with ideologies and self-interests to gain primacy in policy making. Evidence can make a difference, particularly in countries that take pragmatic approaches to health problems like Vietnam.
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(2015)ThesisViolent offending and injecting drug use (IDU) are highly comorbid, serious behaviours. Despite extensive empirical investigation, the mechanisms underpinning this comorbidity remain unclear, which is, in part, due to a widespread assumption that drug use causes violence. In an effort to better understand the liability to violent offending among IDU, this thesis aimed to answer three major unresolved issues: (i) Does drug use cause violence or do underlying factors predispose individuals to drug use and violence? (ii) Is there heterogeneity in the nature of, and risk profiles for, violent offending? (iii) Are risks for violent offending specific to IDU? Addressing these issues was possible through quantitative examination of two large epidemiological datasets: one of community-based IDU (N=300) and a large treatment-based case-control sample (N=1,927). Analyses were structured according to a developmental framework that has not previously been used in this area. This framework focuses on the impact of early life predisposing factors on long term adverse behavioural outcomes. Violent offending was found to be highly prevalent among IDU, with a significant minority (approximately one-third) having committed a serious, injurious violent act. Findings regarding the risks for the likelihood (Chapter Two), severity (Chapter Three), stability (Chapter Four) and specificity (Chapter Five) of violent offending were remarkably consistent across the Chapters. Childhood psychopathology, higher scores on aggressive and impulsive trait measures, and childhood maltreatment were found to be strongly, positively correlated with the initial liability to violent offending. Substance use, on the other hand, appeared to play a greater role in the maintenance of violent behaviour. The findings further indicated that heterogeneity in violent patterns was best explained by the extent of cumulative exposure to early-life and substance use risks, such that IDU with greater early-life risk exposure engaged in more stable, serious violent behaviour. The antisocial markers noted among violent IDU were absent in a matched Control group, supporting a hypothesis of risk specificity for violence. This thesis provides new information to a growing literature regarding the substance use-violent offending association, and has implications for the early identification and intervention in individuals at high risk for an adverse developmental course
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(2016)ThesisChronic non-cancer pain (CNCP) is a worldwide, common complaint and has a major impact on the individual and community in terms of social, financial and health costs. To date, research has been limited in a number of areas, including the association of CNCP with suicidality, the nature of pharmaceutical opioid use in people living with CNCP, the prevalence of Borderline Personality Disorder (BPD) in people living with CNCP, and associations between suicidality (i.e. ideation, plans and attempts) and problematic opioid use (e.g. dependence) in this population. This thesis aimed to address these gaps using two data sources: the 2007 Australian National Survey of Mental Health and Well-being, and data from a large, national community survey of people living with CNCP, the Pain and Opioids IN Treatment (POINT) study. The studies included in this thesis aimed to: 1) examine the association of CNCP with suicidality in the Australia population; 2) describe the formation of the POINT cohort to examine prescription opioid use in CNCP; 3) examine the characteristics of CNCP patients prescribed pharmaceutical opioids; 4) examine characteristics associated with pharmaceutical opioid dose and pharmaceutical opioid dependence in the POINT cohort; 5) determine the prevalence of suicidality and independent predictors of general and pain-specific risk factors to suicidality in the POINT cohort, and 6) explore BPD in the POINT cohort and associations with problematic pharmaceutical opioid use and suicidality. There were a number of important findings from this thesis. Firstly, in the POINT cohort, a large proportion consumed opioids in the high range (over 90mg of oral morphine equivalents mg per day) high-range opioid consumption was associated with problematic opioid use. Secondly, suicidality was common in people living with CNCP, especially in people prescribed opioids for CNCP. Multivariable regressions suggested that an individual’s confidence in coping with their pain was the only independent factor that was predictive of past 12-month progression from ideation to suicide attempt. Finally, screening positively for BPD was high amongst this sample and was associated with pharmaceutical opioid dependence and suicidality. Clinical and research implications are discussed in terms of the need for a multidisciplinary approach to CNCP and the need for appropriate screening for the use of pharmaceutical opioids in the treatment of CNCP.
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(2015)ThesisAlcohol and cannabis, the most commonly used substances in most developed countries, are associated with a range of adverse consequences. Although less prevalent, the use of ecstasy and new psychoactive substances (NPS) that mimic the effects of traditional illicit drugs, are associated with significant harms. As such, early and effective prevention is critical. School is the ideal setting to deliver prevention, however existing programs are limited in their efficacy, sustainability and ability to engage students. In addition, there are no existing evidence-based prevention programs for NPS. The overall aim of this thesis was to advance responses to school-based prevention for alcohol and other drug (AOD) use by investigating the utility of the Internet in overcoming these limitations. A systematic review demonstrated the efficacy of computer- and Internet-based prevention programs and highlighted a lack of replication in the field. Building on this, the existing Internet-based Climate Schools: Alcohol and Cannabis course was validated through a cluster randomised controlled trial (RCT) in 13 schools (N=1103 students). The intervention was effective in increasing alcohol and cannabis knowledge, reducing alcohol intentions and was well-liked by teachers and students, thereby providing support for the use of the Internet to deliver AOD prevention. Using the Climate Schools framework as a basis, the first universal Internet-based prevention program for ecstasy and NPS was developed in close consultation with students and health professionals. To determine the efficacy of the Climate Schools: Ecstasy & Emerging Drugs module a cluster RCT was run in 11 schools (N=1126 students). Results indicated that ecstasy and NPS use was low among students, and the intervention was effective in increasing short-term knowledge about ecstasy and NPS and reducing future intentions to use NPS. Overall, this thesis makes a unique contribution by empirically demonstrating the value of the Internet in overcoming barriers to effective school-based AOD prevention. Of most importance, the first online school-based prevention program for ecstasy and NPS was developed and evaluated. Due to their online and universal nature, the Climate Schools programs can be readily and sustainably implemented and have the potential to make a broad impact in Australia and worldwide.