Externalizing Risk Pathways for Adolescent Substance Use and Its Developmental Onset: A Canadian Birth Cohort Study: Trajectoires de comportements extériorisés et le risque pour l'initiation et l'usage de substances des adolescents : Une étude de cohorte de naissance canadienne.

OBJECTIVE: Only a minority of drug and alcohol users develops a substance use disorder. Previous studies suggest that this differential vulnerability commonly reflects a developmental trajectory characterized by diverse externalizing behaviors. In this study, we examined the relation between child and adolescent externalizing behaviors and adolescent substance use in a prospectively followed Canadian birth cohort, accounting for the temporal sequence of a wide variety of contributing factors. METHODS: Two hundred and forty-two adolescents followed since birth (date range: 1996 to 2012) were assessed on externalizing behavior (age 17 months to 16 years), alcohol and cannabis use at age 16, age of alcohol use onset, family history of substance use problems, family functioning (age 11 to 15), sensation seeking (age 16), prenatal substance exposure, socioeconomic status (age 1 to 9), and sex. RESULTS: Age of alcohol use onset was predicted by a family history of substance use problems, externalizing traits from ages 6 to 10 and 11 to 16, sensation seeking at age 16, prenatal alcohol and tobacco exposure and family functioning at ages 11 to 15. High frequencies of alcohol and cannabis use at age 16 were both predicted by externalizing traits from ages 11 to 16, a family history of substance use problems and sensation seeking after controlling for other individual, environmental and familial variables. The association between familial substance use problems and substance use during adolescence was partially mediated by externalizing traits from age 11 to 16. CONCLUSIONS: The present findings provide prospective evidence for a developmental risk pathway for adolescent substance use, potentially identifying those who could benefit from early interventions.

Age of Cannabis Use Onset and Adult Drug Abuse Symptoms: A Prospective Study of Common Risk Factors and Indirect Effects.

The present study examined 1) whether the associations between cannabis use (CU) age of onset and drug abuse by 28 y remain when controlling for risk factors in childhood, adolescence and early adulthood; and 2) the developmental pathways from early risk factors to drug abuse problems. Participants from a longitudinal sample of boys of low socioeconomic status ( N = 1,030) were followed from 6 to 28 y. We examined the self-reported CU onset between the ages of 13 and 17 y and drug abuse symptoms by 28 y. The odds of developing any drug abuse symptoms by 28 y were reduced by 31% for each year of delayed CU onset (OR = 0.69). Cannabis, alcohol and other drug frequency at 17 y mediated this association. Still, even when taking that frequency of use into account, adolescents who started using cannabis before 15 y were at a higher risk of developing drug abuse symptoms by age 28 y. Significant indirect effects were found from early adolescent delinquency and affiliation with deviant friends to drug abuse symptoms at 28 y through CU age of onset and substance use frequency at 17 y. The results suggest more clearly than before that prevention programs should aim at delaying CU onset to prevent or reduce drug abuse in adulthood. Furthermore, prevention programs targeting delinquency and/or affiliation with deviant friends in childhood or early adolescence could indirectly reduce substance abuse in adulthood without addressing substance use specifically.

Parental characteristics associated with childcare use during the first 4 years of life: results from a representative cohort of Québec families.

OBJECTIVE: Studies have shown that children growing up in socio-economically disadvantaged families have poorer cognitive scores than children growing up in more advantaged families, and that high-quality childcare services can reduce this gap. This effect may be attenuated, however, if disadvantaged families are less likely than better-off families to use childcare and if they use childcare of lower quality. The aim of this study was to identify factors related to parental decisions to use formal and informal childcare. METHODS: Data were obtained from the Quebec Longitudinal Study of Child Development, a birth cohort of children born in 1997/1998 in the Canadian province of Quebec (n=1,504). Children receiving formal (e.g., family and centre) and informal (e.g., grandparents, aunt, nanny) childcare from 5 months to 4 years of age were compared to those receiving exclusively parental care on key psycho-socio-economic family factors. RESULTS: Maternal unemployment during pregnancy, younger maternal age (at initiation of childbearing) and higher number of siblings (e.g., > or = 2) were related to a lower probability of a child receiving either formal or informal childcare (compared to parental care). In addition, low levels of maternal education, higher levels of overprotection, and lower levels of home stimulation were related to a lower probability of a child receiving formal childcare, but not informal childcare. Insufficient income was not associated with childcare use. CONCLUSION: Maternal education and maternal employment were the main socio-economic barriers to childcare participation in a province offering low-cost childcare services. Future initiatives may consider prioritizing childcare access to underserved children and other (e.g., literacy-based) interventions to facilitate access.

Daycare attendance, stress, and mental health.

OBJECTIVE: Daycare stress can be indexed by cortisol, and elevated levels of cortisol have been implicated in the onset and development of mental health disorders. Our objective was to quantify the associations between daycare and cortisol and to identify individual and environmental conditions under which daycare attendance is associated with cortisol concentrations. METHODS: We used Cohen effect size statistics to quantify these associations and to compare them across 11 published studies that were identified with MEDLINE and PsycINFO. RESULTS: Cortisol levels increased during the daycare day, whereas they decreased when children stayed at home. The mean effect size was d = 0.72. The magnitude of the daycare-stress relation seemed to vary under 3 specific conditions. First, the effect size was larger for children in low-quality daycare (d = 1.15), whereas there was essentially little or no effect for children in high-quality daycare (d = 0.10). Second, the effect size was larger for preschoolers (aged 39 to 59 months) (d = 1.17) than for infants (aged 3 to 16 months) (d = 0.11) or school-aged children (aged 84 to 106 months) (d = 0.09). Third, children with difficult temperaments in daycare were more likely to exhibit a rising pattern of cortisol, compared with children who were not difficult. CONCLUSIONS: Our review suggests that daycare attendance in relatively low-quality daycare conditions and for children with difficult temperaments may result in atypical cortisol elevation. Although the link between atypical cortisol elevation and mental health requires further study, programs aimed at improving the quality of daycare services during the preschool years are expected to lead to better physiological adaptation to daycare and to reduce the risks of mental health problems.