Cannabis law and cannabis-related harm.

At the present time there are continuing debates on the legal status of cannabis in New Zealand. Many of these debates have not given sufficient consideration to evidence concerning cannabis-related harm, much of which has been gathered here in New Zealand by the Christchurch Health and Development Study (CHDS) and the Dunedin Multidisciplinary Health and Development Study (DMHDS). We present a summary of this evidence, and recommendations for a cautious path forward for changing cannabis laws in New Zealand that aims at reducing cannabis-related harm.

Childhood predictors of adult adiposity: findings from a longitudinal study.

AIMS: The increasing prevalence of overweight and obesity has become a key challenge for New Zealand. The purpose of the present study was to examine childhood risk factors for adult adiposity in a longitudinal birth cohort. METHODS: Data were gathered from the Christchurch Health and Development Study (CHDS), a birth cohort of 1,265 children born in Christchurch in 1977. Associations were examined between socio-demographic background, perinatal factors, infant and child characteristics, family functioning/child maltreatment and adiposity at ages 30 and 35 years. Adiposity was assessed using body mass index scores. RESULTS: At ages 30 and 35, approximately one-third of cohort members were overweight and one-fifth were obese. Generalised estimating equation models showed that statistically significant (p<.05) predictors of later adiposity and overweight/obesity were: male gender, being born into a single-parent family, having parents with larger body size, higher early infant growth, limited or no breastfeeding, lower levels of cognitive ability and exposure to severe sexual abuse. CONCLUSIONS: Overweight and obesity was associated with social and family background, biological endowment, cognitive ability and childhood adversity factors. These findings may assist in the development of structured adiposity intervention programmes in conjunction with established community organisations specialising in child and family health.

Childhood predictors of adult adiposity: findings from a longitudinal study.

AIMS: The increasing prevalence of overweight and obesity has become a key challenge for New Zealand. The purpose of the present study was to examine childhood risk factors for adult adiposity in a longitudinal birth cohort. METHODS: Data were gathered from the Christchurch Health and Development Study (CHDS), a birth cohort of 1,265 children born in Christchurch in 1977. Associations were examined between socio-demographic background, perinatal factors, infant and child characteristics, family functioning/child maltreatment and adiposity at ages 30 and 35 years. Adiposity was assessed using body mass index scores. RESULTS: At ages 30 and 35, approximately one-third of cohort members were overweight and one-fifth were obese. Generalised estimating equation models showed that statistically significant (p<.05) predictors of later adiposity and overweight/obesity were: male gender, being born into a single-parent family, having parents with larger body size, higher early infant growth, limited or no breastfeeding, lower levels of cognitive ability and exposure to severe sexual abuse. CONCLUSIONS: Overweight and obesity was associated with social and family background, biological endowment, cognitive ability and childhood adversity factors. These findings may assist in the development of structured adiposity intervention programmes in conjunction with established community organisations specialising in child and family health.

Microsatellite polymorphisms associated with human behavioural and psychological phenotypes including a gene-environment interaction.

BACKGROUND: The genetic and environmental influences on human personality and behaviour are a complex matter of ongoing debate. Accumulating evidence indicates that short tandem repeats (STRs) in regulatory regions are good candidates to explain heritability not accessed by genome-wide association studies. METHODS: We tested for associations between the genotypes of four selected repeats and 18 traits relating to personality, behaviour, cognitive ability and mental health in a well-studied longitudinal birth cohort (n = 458-589) using one way analysis of variance. The repeats were a highly conserved poly-AC microsatellite in the upstream promoter region of the T-box brain 1 (TBR1) gene and three previously studied STRs in the activating enhancer-binding protein 2-beta (AP2-ß) and androgen receptor (AR) genes. Where significance was found we used multiple regression to assess the influence of confounding factors. RESULTS: Carriers of the shorter, most common, allele of the AR gene's GGN microsatellite polymorphism had fewer anxiety-related symptoms, which was consistent with previous studies, but in our study this was not significant following Bonferroni correction. No associations with two repeats in the AP2-ß gene withstood this correction. A novel finding was that carriers of the minor allele of the TBR1 AC microsatellite were at higher risk of conduct problems in childhood at age 7-9 (p = 0.0007, which did pass Bonferroni correction). Including maternal smoking during pregnancy (MSDP) in models controlling for potentially confounding influences showed that an interaction between TBR1 genotype and MSDP was a significant predictor of conduct problems in childhood and adolescence (p < 0.001), and of self-reported criminal behaviour up to age 25 years (p ≤ 0.02). This interaction remained significant after controlling for possible confounders including maternal age at birth, socio-economic status and education, and offspring birth weight. CONCLUSIONS: The potential functional importance of the TBR1 gene's promoter microsatellite deserves further investigation. Our results suggest that it participates in a gene-environment interaction with MDSP and antisocial behaviour. However, previous evidence that mothers who smoke during pregnancy carry genes for antisocial behaviour suggests that epistasis may influence the interaction.

Exposure to parental separation in childhood and later parenting quality as an adult: evidence from a 30-year longitudinal study.

BACKGROUND: Previous research has documented that exposure to parental separation/divorce during childhood can be associated with long-term consequences into adulthood. This study sought to extend this literature by examining associations between childhood exposure to parental separation/divorce and later parenting behavior as an adult in a New Zealand birth cohort. METHODS: Data were drawn from the Christchurch Health and Development Study (CHDS), a longitudinal study of a birth cohort of 1,265 children born in 1977 in Christchurch, New Zealand. Information about exposure to parental separation and divorce was gathered annually from birth to 15 years. At the 30-year follow-up, all cohort members who had become parents (biological or nonbiological) were assessed on several parenting dimensions (sensitivity, warmth, overreactivity, inconsistency, quality of child management, and physical punishment). RESULTS: The analyses showed that exposure to more frequent parental separation in childhood and adolescence was associated with lower levels of parental sensitivity and warmth, greater overreactivity, and an increased use of physical punishment as a parent, after controlling for a wide range of family socioeconomic and psychosocial factors, and individual child characteristics. CONCLUSIONS: The findings suggest that as exposure to parental separation increases, so does the likelihood of experiencing multiple developmental challenges in childhood and adolescence. As an adult, these life-course experiences can have small but significant associations with the quality of parenting behavior.

Accuracy of Self-report as a Method of Screening for Lifetime Occurrence of Traumatic Brain Injury Events that Resulted in Hospitalization.

BACKGROUND: Traumatic brain injury (TBI) occurs frequently during child and early adulthood, and is associated with negative outcomes including increased risk of drug abuse, mental health disorders and criminal offending. Identification of previous TBI for at-risk populations in clinical settings often relies on self-report, despite little information regarding self-report accuracy. This study examines the accuracy of adult self-report of hospitalized TBI events and the factors that enhance recall. METHODS: The Christchurch Health and Development Study is a birth cohort of 1265 children born in Christchurch, New Zealand, in 1977. A history of TBI events was prospectively gathered at each follow-up (yearly intervals 0-16, 18, 21, 25 years) using parental/self-report, verified using hospital records. RESULTS: At 25 years, 1003 cohort members were available, with 59/101 of all hospitalized TBI events being recalled. Recall varied depending on the age at injury and injury severity, with 10/11 of moderate/severe TBI being recalled. Logistic regression analysis indicated that a model using recorded loss of consciousness, age at injury, and injury severity, could accurately classify whether or not TBI would be reported in over 74% of cases. CONCLUSIONS: This research demonstrates that, even when individuals are carefully cued, many instances of TBI will not recalled in adulthood despite the injury having required a period of hospitalization. Therefore, screening for TBI may require a combination of self-report and review of hospital files to ensure that all cases are identified. (JINS, 2016, 22, 717-723).

Adiposity and psychosocial outcomes at ages 30 and 35.

PURPOSE: To examine associations between adiposity and adult psychosocial outcomes (depressive symptoms, life satisfaction, self-esteem, household income, personal income, savings/investments) in a New Zealand birth cohort, by gender. Adiposity was assessed using Body Mass Index scores classified on a 3-point scale of BMI: <25.0, overweight (25.0-29.9) or obese (≥30). METHODS: Data were gathered via face-to-face and telephone interviews for the Christchurch Health and Development Study (CHDS), comprising a birth cohort of 1265 children born in Christchurch, New Zealand, in 1977. BMI and psychosocial outcome information was collected in 2007 (30 years; n = 977) and in 2012 (35 years; n = 923). RESULTS: Population-averaged regression modeling showed evidence of statistically significant (p < 0.05) associations between increasing adiposity and adverse psychosocial outcomes for females, but not for males. After adjustment for child and family background covariates the strength of the associations for females was reduced; with four associations (depressive symptoms, life satisfaction, equivalized household income and savings/investments) remaining statistically significant (p < 0.05). In contrast, for males there was a significant (p = 0.008) positive association between adiposity and higher personal net weekly income after covariate adjustment. CONCLUSIONS: The findings suggest evidence of gender differences in the associations between adiposity and psychosocial outcomes. For females, there were small but pervasive tendencies for increasing adiposity to be related to more adverse mental health, psychological well-being and economic outcomes; whereas for males adiposity was either unrelated to these outcomes, or in the case of personal income, associated with greater economic advantage. The implications of these findings are discussed.

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.

Heavier smoking may lead to a relative increase in waist circumference: evidence for a causal relationship from a Mendelian randomisation meta-analysis. The CARTA consortium.

OBJECTIVES: To investigate, using a Mendelian randomisation approach, whether heavier smoking is associated with a range of regional adiposity phenotypes, in particular those related to abdominal adiposity. DESIGN: Mendelian randomisation meta-analyses using a genetic variant (rs16969968/rs1051730 in the CHRNA5-CHRNA3-CHRNB4 gene region) as a proxy for smoking heaviness, of the associations of smoking heaviness with a range of adiposity phenotypes. PARTICIPANTS: 148,731 current, former and never-smokers of European ancestry aged ≥ 16 years from 29 studies in the consortium for Causal Analysis Research in Tobacco and Alcohol (CARTA). PRIMARY OUTCOME MEASURES: Waist and hip circumferences, and waist-hip ratio. RESULTS: The data included up to 66,809 never-smokers, 43,009 former smokers and 38,913 current daily cigarette smokers. Among current smokers, for each extra minor allele, the geometric mean was lower for waist circumference by -0.40% (95% CI -0.57% to -0.22%), with effects on hip circumference, waist-hip ratio and body mass index (BMI) being -0.31% (95% CI -0.42% to -0.19), -0.08% (-0.19% to 0.03%) and -0.74% (-0.96% to -0.51%), respectively. In contrast, among never-smokers, these effects were higher by 0.23% (0.09% to 0.36%), 0.17% (0.08% to 0.26%), 0.07% (-0.01% to 0.15%) and 0.35% (0.18% to 0.52%), respectively. When adjusting the three central adiposity measures for BMI, the effects among current smokers changed direction and were higher by 0.14% (0.05% to 0.22%) for waist circumference, 0.02% (-0.05% to 0.08%) for hip circumference and 0.10% (0.02% to 0.19%) for waist-hip ratio, for each extra minor allele. CONCLUSIONS: For a given BMI, a gene variant associated with increased cigarette consumption was associated with increased waist circumference. Smoking in an effort to control weight may lead to accumulation of central adiposity.

Genome-Wide Meta-Analysis of Longitudinal Alcohol Consumption Across Youth and Early Adulthood.

The public health burden of alcohol is unevenly distributed across the life course, with levels of use, abuse, and dependence increasing across adolescence and peaking in early adulthood. Here, we leverage this temporal patterning to search for common genetic variants predicting developmental trajectories of alcohol consumption. Comparable psychiatric evaluations measuring alcohol consumption were collected in three longitudinal community samples (N=2,126, obs=12,166). Consumption-repeated measurements spanning adolescence and early adulthood were analyzed using linear mixed models, estimating individual consumption trajectories, which were then tested for association with Illumina 660W-Quad genotype data (866,099 SNPs after imputation and QC). Association results were combined across samples using standard meta-analysis methods. Four meta-analysis associations satisfied our pre-determined genome-wide significance criterion (FDR<0.1) and six others met our 'suggestive' criterion (FDR<0.2). Genome-wide significant associations were highly biological plausible, including associations within GABA transporter 1, SLC6A1 (solute carrier family 6, member 1), and exonic hits in LOC100129340 (mitofusin-1-like). Pathway analyses elaborated single marker results, indicating significant enriched associations to intuitive biological mechanisms, including neurotransmission, xenobiotic pharmacodynamics, and nuclear hormone receptors (NHR). These findings underscore the value of combining longitudinal behavioral data and genome-wide genotype information in order to study developmental patterns and improve statistical power in genomic studies.

Psychosocial sequelae of cannabis use and implications for policy: findings from the Christchurch Health and Development Study.

BACKGROUND: The Christchurch Health and Development Study is a longitudinal study of a birth cohort of 1265 children who were born in Christchurch, New Zealand, in 1977. This cohort has now been studied from birth to the age of 35. SCOPE OF THIS REVIEW: This article examines a series of findings from the CHDS that address a range of issues relating to the use of cannabis amongst the cohort. These issues include: (a) patterns of cannabis use and cannabis dependence; (b) linkages between cannabis use and adverse educational and economic outcomes; (c) cannabis and other illicit drug use; (d) cannabis and psychotic symptoms; (e) other CHDS findings related to cannabis; and (f) the consequences of cannabis use for adults using cannabis regularly. FINDINGS: In general, the findings of the CHDS suggest that individuals who use cannabis regularly, or who begin using cannabis at earlier ages, are at increased risk of a range of adverse outcomes, including: lower levels of educational attainment; welfare dependence and unemployment; using other, more dangerous illicit drugs; and psychotic symptomatology. It should also be noted, however, that there is a substantial proportion of regular adult users who do not experience harmful consequences as a result of cannabis use. CONCLUSIONS: Collectively, these findings suggest that cannabis policy needs to be further developed and evaluated in order to find the best way to regulate a widely-used, and increasingly legal substance.

Tobacco smoking and cannabis use in a longitudinal birth cohort: evidence of reciprocal causal relationships.

BACKGROUND: There is evidence of associations between tobacco and cannabis use that are consistent with both a classical stepping-stone scenario that posits the transition from tobacco use to cannabis use ('gateway' effect of tobacco) and with the reverse process leading from cannabis use to tobacco abuse ('reverse gateway' effect of cannabis). The evidence of direct causal relationships between the two disorders is still missing. METHODS: We analysed data from the Christchurch Health and Development Study (CHDS) longitudinal birth cohort using advanced statistical modelling to control for fixed sources of confounding and to explore causal pathways. The data were analysed using both: (a) conditional fixed effects logistic regression modelling; and (b) a systematic structural equation modelling approach previously developed to investigate psychiatric co-morbidities in the same cohort. RESULTS: We found significant (p<0.05) associations between the extent of cannabis use and tobacco smoking and vice versa, after controlling for non-observed fixed confounding factors and for a number of time-dynamic covariate factors (major depression, alcohol use disorder, anxiety disorder, stressful life events, deviant peer affiliations). Furthermore, increasing levels of tobacco smoking were associated with increasing cannabis use (p=0.02) and vice versa (p<0.001) over time. CONCLUSIONS: Our results lend support to the notion of both of 'gateway' and 'reverse gateway' effects. That is, the association between tobacco and cannabis use arises from a reciprocal feedback loop involving simultaneous causation between tobacco use disorder and cannabis use disorder.

The role of peri-traumatic stress and disruption distress in predicting post-traumatic stress disorder symptoms following exposure to a natural disaster.

BACKGROUND: Few studies have examined the contribution of specific disaster-related experiences to post-traumatic stress disorder (PTSD) symptoms. AIMS: To examine the roles of peri-traumatic stress and distress due to lingering disaster-related disruption in explaining linkages between disaster exposure and PTSD symptoms among a cohort exposed to the 2010-2011 Canterbury (New Zealand) earthquakes. METHOD: Structural equation models were fitted to data obtained from the Christchurch Health and Development Study at age 35 (n=495), 20-24 months following the onset of the disaster. Measures included: earthquake exposure, peri-traumatic stress, disruption distress and PTSD symptoms. RESULTS: The associations between earthquake exposure and PTSD symptoms were explained largely by the experience of peri-traumatic stress during the earthquakes (ß=0.189, P<0.0001) and disruption distress following the earthquakes (ß=0.105, P<0.0001). CONCLUSIONS: The results suggest the importance of minimising post-event disruption distress following exposure to a natural disaster. DECLARATION OF INTEREST: None. COPYRIGHT AND USAGE: © The Royal College of Psychiatrists 2015. This is an open access article distributed under the terms of the Creative Commons Non-Commercial, No Derivatives (CC BY-NC-ND) licence.

Perceptions of distress and positive consequences following exposure to a major disaster amongst a well-studied cohort.

OBJECTIVES: Research on the impact of natural disasters on health and well-being faces several methodological challenges, including: sampling issues; exposure assessment; and outcome measurement. The present study used a comprehensive measure of disaster exposure to assess relationships between exposure to the Canterbury (New Zealand) Earthquakes of 2010-2011 and both: (a) self-reported distress and (b) positive outcomes; and also investigated gender differences in reports. METHODS: Data were gathered from the Christchurch Health and Development Study, a 35-year longitudinal study. The study examined data from 495 individuals exposed to the Canterbury Earthquakes for who complete data on exposure and reactions to the earthquakes at age 35 were available. RESULTS: Participants with higher levels of exposure to the earthquakes reported significantly (p<0.0001) higher levels of distress due to fear, death and injury, and disruption caused by the earthquakes. Higher levels of exposure to the earthquakes were also associated with significantly (p<0.0001) higher levels of reporting positive consequences following the earthquakes. Women reported significantly (p<0.0001) greater distress than men and significantly (p<0.001) greater positive consequences. CONCLUSIONS: Higher levels of exposure to disaster were associated with higher levels of distress, but also with higher levels of self-reported positive outcomes, with females reporting higher levels of both positive and negative outcomes. The findings highlight the need for comprehensive assessment of disaster exposure, to consider gender and other group differences in reactions to disaster exposure, and for studies of disasters to examine both positive and negative consequences.

Leaving school without qualifications and mental health problems to age 30.

PURPOSE: To examine the associations between leaving school without qualifications and subsequent mental health to age 30, using data gathered over the course of a 30-year longitudinal study. METHODS: Data were gathered over the course of a 30-year study (Christchurch Health and Development Study) of a birth cohort of 1265 children, born in Christchurch in 1977. This cohort has been studied on 22 occasions from birth to age 30. As part of this study, information was gathered on: (a) school leaving qualifications, (b) mental health problems from 18 to 30; and (c) prospectively assessed childhood and adolescent factors including: child and family background; family violence and child abuse; and adolescent mental health problems. RESULTS: Leaving school without qualifications was associated with increased risks of subsequent: major depression (OR = 1.37 at 95 % CI 1.05-1.78, p = 0.019); anxiety disorder (OR = 1.99 at 95 % CI 1.55-2.57, p < 0.001); suicidal ideation/attempt (OR = 1.60 at 95 % CI 1.15-2.36, p = 0.005); alcohol abuse/dependence (OR = 1.54 at 95 % CI 1.20-1.98, p < 0.001); and illicit substance abuse/dependence (OR = 2.97 at 95 % CI 2.16-4.07, p < 0.001). Adjustment for the covariate factors above (family social background; family violence; child abuse and adolescent mental health problems) reduced these associations substantially and to the point of statistical non-significance. CONCLUSIONS: The findings of this study suggest that there was no direct causal association between leaving school without qualifications and subsequent mental health problems. Associations were explained by the linkages between leaving school without qualifications and: child and family social background; and mental health around the point of school leaving.

DUF1220 copy number is linearly associated with increased cognitive function as measured by total IQ and mathematical aptitude scores.

DUF1220 protein domains exhibit the greatest human lineage-specific copy number expansion of any protein-coding sequence in the genome, and variation in DUF1220 copy number has been linked to both brain size in humans and brain evolution among primates. Given these findings, we examined associations between DUF1220 subtypes CON1 and CON2 and cognitive aptitude. We identified a linear association between CON2 copy number and cognitive function in two independent populations of European descent. In North American males, an increase in CON2 copy number corresponded with an increase in WISC IQ (R (2) = 0.13, p = 0.02), which may be driven by males aged 6-11 (R (2) = 0.42, p = 0.003). We utilized ddPCR in a subset as a confirmatory measurement. This group had 26-33 copies of CON2 with a mean of 29, and each copy increase of CON2 was associated with a 3.3-point increase in WISC IQ (R (2) = 0.22, p = 0.045). In individuals from New Zealand, an increase in CON2 copy number was associated with an increase in math aptitude ability (R (2) = 0.10 p = 0.018). These were not confounded by brain size. To our knowledge, this is the first study to report a replicated association between copy number of a gene coding sequence and cognitive aptitude. Remarkably, dosage variations involving DUF1220 sequences have now been linked to human brain expansion, autism severity and cognitive aptitude, suggesting that such processes may be genetically and mechanistically inter-related. The findings presented here warrant expanded investigations in larger, well-characterized cohorts.