Mental health comorbidities following peer victimization across childhood and adolescence: a 20-year longitudinal study.

BACKGROUND: Peer victimization is associated with a wide range of mental health problems in youth, yet few studies described its association with mental health comorbidities. METHODS: To test the association between peer victimization timing and intensity and mental health comorbidities, we used data from 1216 participants drawn from the Quebec Longitudinal Study of Child Development, a population-based birth cohort. Peer victimization was self-reported at ages 6-17 years, and modeled as four trajectory groups: low, childhood-limited, moderate adolescence-emerging, and high-chronic. The outcomes were the number and the type of co-occurring self-reported mental health problems at age 20 years. Associations were estimated using negative binomial and multinomial logistic regression models and adjusted for parent, family, and child characteristics using propensity score inverse probability weights. RESULTS: Youth in all peer victimization groups had higher rates of co-occurring mental health problems and higher likelihood of comorbid internalizing-externalizing problems [odds ratios ranged from 2.06, 95% confidence interval (CI) 1.52-2.79 for childhood-limited to 4.34, 95% CI 3.15-5.98 for high-chronic victimization] compared to those in the low victimization group. The strength of these associations was highest for the high-chronic group, followed by moderate adolescence-emerging and childhood-limited groups. All groups also presented higher likelihood of internalizing-only problems relative to the low peer victimization group. CONCLUSIONS: Irrespective of timing and intensity, self-reported peer victimization was associated with mental health comorbidities in young adulthood, with the strongest associations observed for high-chronic peer victimization. Tackling peer victimization, especially when persistent over time, could play a role in reducing severe and complex mental health problems in youth.

Early Childhood Factors Associated With Peer Victimization Trajectories From 6 to 17 Years of Age.

OBJECTIVES: To describe (1) the developmental trajectories of peer victimization from 6 to 17 years of age and (2) the early childhood behaviors and family characteristics associated with the trajectories. METHODS: We used data from 1760 children enrolled in the Quebec Longitudinal Study of Child Development, a population-based birth cohort. Participants self-reported peer victimization at ages 6, 7, 8, 10, 12, 13, 15, and 17 years. Participants' behavior and family characteristics were measured repeatedly between ages 5 months and 5 years. RESULTS: We identified 4 trajectories of peer victimization from 6 to 17 years of age: low (32.9%), moderate-emerging (29.8%), childhood-limited (26.2%), and high-chronic (11.1%). Compared with children in the low peer victimization trajectory, children in the other 3 trajectories were more likely to exhibit externalizing behaviors in early childhood, and those in the high-chronic and moderate-emerging trajectories were more likely to be male. Paternal history of antisocial behavior was associated with moderate-emerging (odds ratio [OR] = 1.54; 95% confidence interval [CI] = 1.09-2.19) and high-chronic (OR = 1.93; 95% CI = 1.25-2.99) relative to low peer victimization. Living in a nonintact family in early childhood was associated with childhood-limited (OR = 1.48; 95% CI = 1.11-1.97) and high-chronic (OR = 1.59; 95% CI = 1.09-2.31) relative to low peer victimization. CONCLUSIONS: Early childhood externalizing behaviors and family vulnerabilities were associated with the development of peer victimization. Some children entered the cascade of persistent peer victimization at the beginning of primary school. Support to these children and their families early in life should be an important component of peer victimization preventive interventions.

Adolescent internalizing symptoms: The importance of multi-informant assessments in childhood.

BACKGROUND: Childhood internalizing symptoms can be associated with adolescent internalizing symptoms, but only a small proportion of symptomatic children are at long-term risk. Our objectives were to (1) distinguish between typical and atypical levels of internalizing symptoms using mother- and teacher-assessments and (2) test the association between childhood internalizing symptoms and adolescent generalized anxiety, depression, and social phobia symptoms in boys and girls. METHODS: Multi-trajectory models were used to estimate the evolution of mother- and teacher-reported internalizing symptoms across childhood (1.5 to 12 years) in a large population-based cohort (n = 1431). Multiple linear regression models were implemented to estimate the association between childhood group membership of internalizing symptoms and self-reported specific internalizing symptoms at 15 years by sex. RESULTS: Five groups of childhood internalizing symptoms were identified: Mother & teacher low (22.6%), Mother moderate/teacher low (37.9%), Mother moderate/teacher high (18.3%), Mother high/teacher low (11.8%) and Mother & teacher high (9.5%). Multiple linear regression models showed that compared to the low group, (1) boys in the high group reported higher social phobia symptoms (p = 0.04), (2) girls in the high group reported higher depression (p = 0.01) and generalized anxiety (p < 0.01) symptoms, and (3) girls in the moderate/high group reported higher generalized anxiety symptoms (p = 0.02) in adolescence. LIMITATIONS: The main limitation is that mothers' and teachers' assessments mostly covered different developmental periods. CONCLUSIONS: A multi-informant assessment of childhood internalizing symptoms improves adolescent specific internalizing symptoms identification in a general population sample over reliance on a single informant.

Beyond intention-to-treat: The effect of brief counseling for tobacco cessation in secondary analyses of a cluster randomized controlled trial in Swedish dental clinics.

In experimental studies the assigned intervention measures the received intervention if full protocol adherence is achieved, but this is rarely the case in public health. The objective of this study was to estimate the effect of a brief counseling intervention delivered in Swedish dental clinics on tobacco use cessation, taking non-adherence into account. We conducted three secondary analyses. In a per-protocol analysis the experimental counseling delivered as intended was contrasted to usual care (control). In an as-treated analysis individuals were compared according to the counseling components actually received, disregarding randomization. In an instrumental variable analysis the effect of the intervention among those who would always be treated as assigned was estimated. Logistic regression was used to examine the association between tobacco cessation outcomes (seven-day abstinence, three-month abstinence, half-reduction, quit attempts) and the defined exposure to the intervention. Protocol adherence in the intervention group was 73.4%. The per-protocol analysis closely replicated the results of the intention-to-treat analysis, showing a statistically significant effect of the brief counseling on the reduction in tobacco consumption OR = 1.81, 95% CI [1.06, 3.07], but no significant effect for other outcomes. In the as-treated analysis, receiving more counseling components compared with no tobacco counseling increased the likelihood of half-reduction. The instrumental variable yielded biased results. We conclude that despite application problems, conducting per-protocol, as-treated and instrumental variable analyses in randomized trials where experimental conditions are not strictly standardized strengthens and puts in context the inference based on intention-to-treat analysis.