Concurrent and prospective associations between family socioeconomic status, social support and salivary diurnal and hair cortisol in adolescence.

BACKGROUND: Exposure to socioeconomic adversity is hypothesized to impact hypothalamic-pituitary-adrenal (HPA) axis activity and cortisol secretion, but existing evidence is inconsistent. Yet, few studies have investigated this association using a developmental approach that considers potential protective contextual factors. This study examined the role of stability and changes in family socioeconomic status (SES) in the prediction of multiple cortisol indicators and tested whether social support moderated these associations. METHODS: Participants were part of a population-based sample of twin pairs recruited at birth. Family SES was assessed in early childhood (ages 0-5) and mid-adolescence (age 14). Social support was assessed at ages 14 and 19. Diurnal cortisol (n = 569) was measured at age 14 at awakening, 30 min later, in the afternoon and evening over four non-consecutive days. Hair cortisol concentration (HCC, n = 704) was measured at age 19. All data were collected before the pandemic and multilevel regression models were conducted to account for the nested data structure. RESULTS: Youth exposed to lower family SES levels in childhood and mid-adolescence had a flatter diurnal slope and higher HCC compared with those who experienced upward socioeconomic mobility in mid-adolescence. Contrastingly, mid-adolescence SES showed no association with the diurnal slope or HCC for youth from higher-SES households in early childhood. Moreover, youth raised in higher-SES families in early childhood had a higher CAR in mid-adolescence if they reported greater social support in mid-adolescence. Social support also moderated the SES-cortisol association in mid-adolescence, with higher-SES youth showing higher awakening cortisol secretion when reporting more social support. CONCLUSIONS: Our findings support the hypothesis that early socioeconomic adversity sensitizes HPA axis activity to later socioeconomic disadvantage, which may bear consequences for socioemotional and behavioral functioning.

Associations between digital media use and psychotic experiences in young adults of Quebec, Canada: a longitudinal study.

PURPOSE: Digital media use has been associated with psychotic experiences in youth from the community, but the direction of association remains unclear. We aimed to examine between- and within-person associations of digital media use and psychotic experiences in youth. METHODS: The sample included 425 participants aged 18-25 years (82.5% female) from the community, followed between May 2021 and January 2022 over 3 time points-of which 263 participants (61.9%) completed at least 2. Digital media use was self-reported as time spent daily on TV and streaming platforms, social media, and video games over the past 3 months. Psychotic experiences in the past 3 months were measured with the 15-item Community Assessment of Psychic Experiences. Associations between digital media use and psychotic experiences were estimated using a random-intercept cross-lagged panel model. RESULTS: On average, individuals who reported greater digital media use also reported higher levels of psychotic experiences (r = 0.34, 95% CI 0.15, 0.53). However, a person's variation in digital media use, relative to their personal average, was not significantly associated with subsequent variations in their levels of psychotic experiences, or vice-versa. Results were similar across TV/streaming, social media and video game use, and after adjusting for age, sex, education, sleep, physical activity, and cannabis use. CONCLUSION: Individuals with a tendency for higher levels of digital media use also had a tendency for higher levels of psychotic experiences. Understanding this association may help personalize mental health interventions for people with psychotic experiences, which may be offered digitally to promote their accessibility.

Association of childhood bullying victimisation with suicide deaths: findings from a 50-year nationwide cohort study.

BACKGROUND: Bullying victimisation has been associated with increased risk of suicide ideation and attempt throughout the lifespan, but no study has yet examined whether it translates to a greater risk of death by suicide. We aimed to determine the association of bullying victimisation with suicide mortality. METHODS: Participants were drawn from the 1958 British birth cohort, a prospective follow-up of all births in 1 week in Britain in 1958. We conducted logistic regressions on 14 946 participants whose mothers reported bullying victimisation at 7 and 11 years with linked information on suicide deaths through the National Health Service Central Register. RESULTS: Fifty-five participants (48 males) had died by suicide between the age 18 and 52 years. Bullying victimisation was associated with suicide mortality; a one standard deviation increases in bullying victimisation linked to an increased odds for suicide mortality [odds ratio (OR) 1.29; 1.02-1.64] during adulthood. The OR attenuated by 11% after adjustment for individual (e.g. behavioural and emotional problems) and familial characteristics (e.g. adverse childhood experiences, 1.18; 0.92-1.51). Analysis of bullying victimisation frequency categories yields similar results: compared with individuals who had not been bullied, those who had been frequently bullied had an increased odds for suicide mortality (OR 1.89; 0.99-3.62). CONCLUSION: Our study suggests that individuals who have been frequently bullied have a small increased risk of dying by suicide, when no other risk factors is considered. Suicide prevention might start in childhood, with bullying included in a range of inter-correlated vulnerabilities encompassing behavioural and emotional difficulties and adverse experiences within the family.

Uncovering the genetic architecture of broad antisocial behavior through a genome-wide association study meta-analysis.

Despite the substantial heritability of antisocial behavior (ASB), specific genetic variants robustly associated with the trait have not been identified. The present study by the Broad Antisocial Behavior Consortium (BroadABC) meta-analyzed data from 28 discovery samples (N = 85,359) and five independent replication samples (N = 8058) with genotypic data and broad measures of ASB. We identified the first significant genetic associations with broad ASB, involving common intronic variants in the forkhead box protein P2 (FOXP2) gene (lead SNP rs12536335, p = 6.32 × 10-10). Furthermore, we observed intronic variation in Foxp2 and one of its targets (Cntnap2) distinguishing a mouse model of pathological aggression (BALB/cJ strain) from controls (BALB/cByJ strain). Polygenic risk score (PRS) analyses in independent samples revealed that the genetic risk for ASB was associated with several antisocial outcomes across the lifespan, including diagnosis of conduct disorder, official criminal convictions, and trajectories of antisocial development. We found substantial genetic correlations of ASB with mental health (depression rg = 0.63, insomnia rg = 0.47), physical health (overweight rg = 0.19, waist-to-hip ratio rg = 0.32), smoking (rg = 0.54), cognitive ability (intelligence rg = -0.40), educational attainment (years of schooling rg = -0.46) and reproductive traits (age at first birth rg = -0.58, father's age at death rg = -0.54). Our findings provide a starting point toward identifying critical biosocial risk mechanisms for the development of ASB.

Polygenic risk score and peer victimisation independently predict depressive symptoms in adolescence: results from the Quebec Longitudinal Study of Children Development.

BACKGROUND: Peer victimisation has been associated with depressive symptoms during adolescence, however not all peer victimised adolescents will exhibit such symptoms. This study tested whether having a genetic predisposition to developing depression increased the risk of experiencing depressive symptoms in peer victimised youth. To date, no study has explored such gene-environment interaction using a polygenic risk score for depression (PRS-depression) in the context of peer victimisation and depressive symptoms in adolescence. METHODS: The sample included 748 participants born in 1997/98 from the Quebec Longitudinal Study of Child Development with genotype data and prospectively collected information on peer victimisation (12-13 years) obtained from both self- and teacher-reports, as well as self-reported depressive symptoms (15-17 years). The PRS-depression was based on the genome-wide association meta-analysis of broad depression by Howard et al. (2019). RESULTS: Self- and teacher-reported peer victimisation in early adolescence were both associated with depressive symptoms in adolescence (ß = 0.34, p < .001; ß = 0.14, p = .001 respectively), and this association remained significant when accounting for PRS-depression (ß = 0.33, p < .001; ß = 0.13, p = .002 respectively). PRS-depression was independently associated with depressive symptoms, but there was no significant PRS-depression by peer victimisation interaction (self-reported and teacher-reported). PRS-depression was correlated with self-reported, but not teacher-reported, peer victimisation. CONCLUSIONS: Our findings suggested that a partial measure of an individual's genetic predisposition to depression, as measured by PRS-depression, and being exposed to peer victimisation (self- and teacher-reported) were independently associated with depressive symptoms in adolescence. Furthermore, PRS-depression did not exacerbate the risk of depressive symptoms among adolescents who had been peer victimised. Lastly, we found evidence of a gene-environment correlation between PRS-depression and self-reported peer victimisation. Future studies are needed to replicate this finding and to further understand the role of genetic predispositions in experiencing depressive symptoms following peer victimisation.

Longitudinal Associations between Prenatal Exposure to Phthalates and Steroid Hormones in Maternal Hair Samples from the SEPAGES Cohort.

We assessed phthalate-hormone associations in 382 pregnant women of the new-generation SEPAGES cohort (2014-2017, France) using improved exposure and outcome assessments. Metabolites from seven phthalate compounds and the replacement di(isononyl)cyclohexane-1,2-dicarboxylate (DINCH) were measured in within-subject pools of repeated urine samples collected at the second and third pregnancy trimesters (≈21 samples/trimester). Metabolites from five steroid hormones were measured in maternal hair samples collected at delivery, reflecting cumulative levels over the previous weeks to months. Adjusted linear regression and Bayesian weighted quantile sum (BWQS) mixture models were performed. Each doubling in third-trimester urinary mono-benzyl phthalate (MBzP) concentrations was associated with an average increase of 13.3% (95% CI: 2.65, 24.9) for ∑cortisol, 10.0% (95% CI: 0.26, 20.7) for ∑cortisone, 17.3% (95% CI: 1.67, 35.4) for 11-dehydrocorticosterone, and 16.2% (95% CI: 2.20, 32.1) for testosterone, together with a suggestive 10.5% (95% CI: -1.57, 24.1) increase in progesterone levels. Each doubling in second-trimester urinary di-isononyl phthalate (DiNP) concentrations was inversely associated with testosterone levels (-11.6%; 95% CI: -21.6, -0.31). For most hormones, a nonsignificant trend toward a positive phthalate mixture effect was observed in the third but not in the second trimester. Our study showed that exposure to some phthalate metabolites, especially MBzP, may affect adrenal and reproductive hormone levels during pregnancy.

The phenotypic associations and gene-environment underpinnings of socioeconomic status and diurnal cortisol secretion in adolescence.

While converging evidence suggests that both environmental and genetic factors underlie variations in diurnal cortisol, the extent to which these sources of influence vary according to socioeconomic status (SES) has seldom been investigated, particularly in adolescence. To investigate whether a distinct genetic and environmental contribution to youth's diurnal cortisol secretion emerges according to family SES and whether the timing of these experiences matters. Participants were 592 twin pairs, who mostly came from middle-income and intact families and for whom SES was measured in childhood and adolescence. Diurnal cortisol was assessed at age 14 at awakening, 30 min later, in the afternoon and evening over four nonconsecutive days. SES-cortisol phenotypic associations were specific to the adolescence period. Specifically, higher awakening cortisol levels were detected in wealthier backgrounds, whereas higher cortisol awakening response (CAR) and diurnal changes were present at both ends of the SES continuum. Moreover, smaller genetic contributions emerged for awakening cortisol in youth from poorer compared to wealthier backgrounds. The results suggest that the relative contribution of inherited factors to awakening cortisol secretion may be enhanced or suppressed depending on the socio-family context, which may help to decipher the mechanisms underlying later adjustment.

Increased urban greenspace in childhood associated with lower inattention deficit among adolescents.

PURPOSE: There is a growing interest in assessing the benefits of exposure to urban greenspace on mental health due to the increased urbanization of youth and concerns for their mental health. We investigated the prospective associations of residential greenspace in childhood and mental health in adolescence. Use of a well-characterized birth cohort permitted adjustment for a range of potential confounding factors including family and neighborhood characteristics in addition to prior mental health problems, and exploration of moderation effects by sex and family socioeconomic status. METHODS: We analyzed longitudinal data collected from 742 urban-dwelling participants of the Quebec Longitudinal Study of Children Development. The Normalized Difference Vegetation Index (NDVI) within 250, 500, and 1000 m buffer zones surrounding the home residence was used to indicate childhood exposure to greenspace. Six self-reported mental health problems at 15/17 years were examined using the Mental Health and Social Inadaptation questionnaire: inattention, hyperactivity/impulsivity, conduct, depression, anxiety, and suicidal ideation. RESULTS: Childhood urban greenspace was associated with lower inattention problems in both females and males. We observed a 0.14 reduced standard deviation (SD) (ß = - 0.14, SE = 0.05, p < 0.01) in relation to an interquartile range (IQR) increase of NDVI (0.15) at the 250 m buffer zone, and similar results were found in 500 m and 1000 m buffer zones. These associations only slightly attenuated after adjustment for individual (sex, childhood mental health), family (family SES, maternal age at birth, parental mental health, family composition), and neighborhood (material and social deprivation) characteristics (ß = - 0.13, SE = 0.06, p = 0.03). No association was found for other mental health problems, and no moderation associations of sex or family socioeconomic status were observed. CONCLUSION:  These findings suggest that increasing residential greenspace in cities may be associated with modest benefits in attentional capacities in youth, necessitating further research to elucidate the underlying mechanisms.

Polygenic risk for aggressive behavior from late childhood through early adulthood.

Twin studies suggest a substantial role for genes in explaining individual differences in aggressive behavior across development. It is unclear, however, how directly measured genetic risk is associated with aggressive behavior at different moments across adolescence and how genes might distinguish developmental trajectories of aggressive behavior. Here, a polygenic risk score derived from the EAGLE-Consortium genome-wide association study of aggressive behavior in children was tested as predictor of latent growth classes derived from those measures in an adolescent population (n = 2229, of which n = 1246 with genetic information) and a high-risk sample (n = 543, of which n = 335 with genetic information). In the population sample, the polygenic risk score explained variation in parent-reported aggressive behavior at all ages and distinguished between stable low aggressive behavior and moderate and high-decreasing trajectories based on parent-report. In contrast, the polygenic risk score was not associated with self- and teacher-reported aggressive behavior, and no associations were found in the high-risk sample. This pattern of results suggests that methodological choices made in genome-wide association studies impact the predictive strength of polygenic risk scores, not just with respect to power but likely also in terms of generalizability and specificity.

Link Between Peer Victimization in College and Cortisol Secretion: Roles of Genetic Vulnerabilities and Social Support.

It is unclear whether peer victimization in college interacts with genetic vulnerabilities or social support in predicting cortisol secretion. This issue was addressed using a sample of 162 Monozygotic and 237 Dizygotic twin pairs (54% females; 86% Whites, 6% Blacks, 6% Asians, 0.3% Native North Americans). At age 19, participants provided hair for cortisol extraction and reported about victimization in college and support by the mother, father, and best friend. Biometric modeling revealed that environmental influences on cortisol secretion were reduced and genetic influences exacerbated when victimization was high. Moderate to high maternal support mitigated the association between victimization and high cortisol secretion. The findings suggest that victimization in college contributes to physical "wear-and-tear", which may be counteracted by social support.

The Association of Childhood Maltreatment, Sex, and Hair Cortisol Concentrations With Trajectories of Depressive and Anxious Symptoms Among Adult Psychiatric Inpatients.

OBJECTIVE: Depression and anxiety symptoms are commonly observed among clinical populations, especially among women and maltreated individuals. Few investigations have, however, assessed the existence of distinct symptoms trajectories among clinical populations and how these relate to childhood maltreatment, sex differences, and stress physiology indexed by hair cortisol concentrations (HCCs). The current study a) identified distinct depression and anxious trajectories in a sample of psychiatric inpatients followed up prospectively from their admission to a psychiatric emergency service, and b) examined whether HCC, childhood maltreatment, and sex independently and jointly predict these trajectories. METHODS: Adult inpatients (n = 402; 55% women) were recruited upon admission to psychiatric emergency service (T1) during which HCC (reflecting cortisol secretion for the last 3 months), childhood maltreatment, and depression and anxiety symptoms were assessed. Symptoms were reevaluated when patients were discharged from the hospital (T2), admitted to outpatient clinics (T3), and 12 months later or at the end of outpatient treatment (T4). RESULTS: Three trajectories were identified for depression and anxiety symptoms. Among men, higher HCC predicted higher odds of evincing chronic depressive symptoms compared with a low stable trajectory (odds ratio [OR] = 3.46, 95% confidence interval [CI] = 1.43-8.40). Greater childhood maltreatment among men predicted higher chances of exhibiting chronic anxious symptoms than the low stable (OR = 1.47, 95% CI = 1.07-2.02) and the high decreasing trajectories (OR = 0.70, 95% CI = 0.51-0.95). Opposite findings were noted for women. CONCLUSIONS: Childhood maltreatment and HCC should be further investigated as predictors of anxious and depressive trajectories, during which sex-specific associations ought to be considered.

Unique and interactive associations of proactive and reactive aggression with cortisol secretion.

The association between aggressive behaviors and diurnal cortisol levels has been debated over the past two decades, as some studies found a negative link between the two, whereas others reported no or a positive association. One possible explanation for these contradictory results is that past studies failed to distinguish between proactive (PROA) and reactive (REA) aggression. The present study examined the unique and joint associations of PROA and REA with three diurnal cortisol indicators: awakening levels, awakening response, and diurnal change. Participants were 542 youths (55.4% girls) followed longitudinally. Teachers evaluated aggressive behaviors when participants were in Grades 4 and 6. In Grade 8, participants provided four saliva samples (i.e., awakening, 30 min thereafter, late afternoon, and bedtime) on four collection days. Controlling for several confounders, multilevel regression analyses revealed an inverse relation between PROA and the CAR in boys who displayed lower or moderate levels of REA, but not in those who exhibited higher levels of REA. No associations emerged with other cortisol indicators. These results are consistent with reports of lower physiological activity in individuals with PROA and underscore the confounding influence of REA in the association between the CAR and proactive aggression.

Early temperamental and biological predictors of dimensions of social withdrawal in childhood.

Social wariness and preference for solitude, two dimensions of social withdrawal, show unique associations with various socioemotional difficulties in childhood, including internalizing and peer problems. However, their early childhood predictors remain vastly undocumented. The present study aimed to examine whether early indicators of reactivity in situations of unfamiliarity such as behavioral inhibition, affect, and cortisol independently, or in interaction with emotion regulation as indexed by vagal tone, predict later social wariness and preference for solitude. Participants were 1209 children from the Quebec Newborn Twin Study. Vagal tone was assessed at 5 months, and behavioral inhibition, affect, and cortisol were assessed at 19 months in situations of unfamiliarity. Mothers, teachers, and peers evaluated social wariness and preference for solitude repeatedly from 4 to 10 years old. Findings show that three temperamental dimensions, social inhibition, nonsocial inhibition, and affect accounted for the variability in reactions to unfamiliarity. Behavioral inhibition to social unfamiliarity at 19 months predicted social wariness during the preschool years. Poor vagal regulation at 5 months exacerbated the risk associated with negative affect at 19 months to predict preference for solitude during the preschool years. Overall, results show that social wariness and preference for solitude may follow different developmental pathways.

Psychological distress of mental health workers during the COVID-19 pandemic: A comparison with the general population in high- and low-incidence regions.

OBJECTIVE: Despite their essential role during this health crisis, little is known about the psychological distress of mental health workers (MHW). METHOD: A total of 616 MHW and 658 workers from the general population (GP) completed an online survey including depressive, anxiety, irritability, loneliness, and resilience measures. RESULTS: Overall, MHW had fewer cases with above cut-off clinically significant depression (19% MHW vs. 27%) or anxiety (16% MHW vs. 29%) than the GP. MHW in high-incidence regions of COVID-19 cases displayed the same levels of depressive and anxiety symptoms than the GP and higher levels compared to MHW from low-incidence regions. MHW in high-incidence regions presented higher levels of irritability and lower levels of resilience than the MHW in low-incidence regions. Moreover, MHW in high-incidence regions reported more feelings of loneliness than all other groups. CONCLUSION: Implications for social and organizational preventive strategies to minimize the distress of MHW in times of crisis are discussed.

Classroom Placement and Twins' Social Behaviors in Elementary School: Providing Empirical Evidence to Inform Educational Policy.

Classroom placement of twins is an ongoing issue for educational policy. Many educational jurisdictions have standard policy most commonly founded in the belief that separation supports individual identity, personal development and academic opportunity. This study examined the effects of classroom placement in a sample of 560 twin pairs whose behaviors were assessed from ages 5 to 12 years. We found no detrimental effect of classroom sharing on twins' social development. In contrast, this study provides evidence that educating twins together is associated with modest positive twins' behaviors and social functioning at school. Implications for educational policies are further discussed.

Promoting better functioning among children exposed to high levels of family adversity: the protective role of childcare attendance.

BACKGROUND: Children exposed to early adversity are vulnerable to cognitive impairments and externalizing behaviors. Attending childcare may, however, partly buffer this detrimental effect by providing social and cognitive stimulation in a secure environment. The aims of this study were (a) to determine whether the association between exposure to adversity and later externalizing behaviors is mediated by children's cognitive abilities, and (b) to examine if childcare attendance moderates this mediation-thereby highlighting a protective function of children's childcare attendance. METHODS: Data come from the Avon Longitudinal Study of Children and Parents (N = 6,149). Exposure to adversity was assessed by maternal reports three times from the second trimester of the mother's pregnancy to the child's fourth year of age. Childcare attendance was assessed on four occasions between eight months and three years of age. Factors explaining differences in childcare attendance were controlled using propensity score weights. Children's cognitive abilities were assessed by the Weschler Intelligence Scale for Children at eight years of age, and externalizing behaviors were reported by mothers using the Development and Well-Being Assessment interview at 10, 13, and 15 years of age. RESULTS: Notably, lower cognitive abilities partly accounted for the higher levels of externalizing behaviors in adolescents exposed to adversity (B indirect effect = 0.02, 95% CI = 0.007-0.03, p < .01). Importantly, childcare attendance moderated this indirect effect. For children exposed to adversity, being in maternal care was associated with lower cognitive abilities which were related to higher levels of externalizing behaviors. On the contrary, for children exposed to adversity, attending childcare was associated with higher cognitive abilities which were linked to lower levels of externalizing behaviors. CONCLUSIONS: Easily accessible community childcare may be a relatively low-cost public health strategy to prevent the emergence of externalizing behavioral problems in adolescence through its positive effects on cognitive abilities.

Associations between developmental trajectories of peer victimization, hair cortisol, and depressive symptoms: a longitudinal study.

BACKGROUND: Peer victimization has been associated with long-lasting risks for mental health. Prior research suggests that stress-related systems underlying adaptation to changing environments may be at play. To date, inconsistent findings have been reported for the hypothalamic-pituitary-adrenal (HPA) axis, and its end product cortisol. This study tested whether peer victimization was associated with hair cortisol concentrations (HCC), and whether this association varied according to sex, timing, and changes in exposure. We also examined whether peer victimization differentially predicted depressive symptoms according to HCC. METHODS: The sample comprised 556 adolescents (42.0%; 231 males) who provided hair for cortisol measurement at 17 years of age. Peer victimization was reported at seven occasions between the ages of 6 and 15 years. RESULTS: Peer victimization was nonlinearly associated with HCC for boys only, whereas changes in peer victimization were related to HCC for boys and girls. Peer victimization predicted more depressive symptoms for all participants, except those with lower HCC. CONCLUSIONS: Our findings provide further support for persistent dysregulation of the HPA axis following exposure to chronic adversity, of which the expression may change according to sex and the severity of victimization.

Polygenic scores differentially predict developmental trajectories of subtypes of social withdrawal in childhood.

BACKGROUND: Children who consistently withdraw from social situations face increased risk for later socioemotional difficulties. Twin studies indicate that genetic factors substantially account for the persistence of social withdrawal over time. However, the molecular genetic etiology of chronic courses of social wariness and preference for solitude, two dimensions of social withdrawal, remains undocumented. The objectives of the present study were (a) to identify high-risk trajectories for social wariness and preference for solitude in childhood and (b) to examine whether falling on these high-risk trajectories can be predicted by specific polygenic scores for mental health traits and disorders and by a general polygenic predisposition to these traits. METHODS: Teachers evaluated 971 genotyped children at five occasions (age 6 to 12 years) from two prospective longitudinal studies, the Quebec Newborn Twin Study and the Quebec Longitudinal Study of Child Development. Developmental trajectories for social wariness and preference for solitude were identified. We tested whether polygenic scores for attention deficit hyperactivity disorder, autism spectrum disorder, depression, loneliness, and subjective well-being, as well as a general mental health genetic risk score derived across these traits, were associated with the developmental trajectories. RESULTS: Polygenic scores differentially predicted social wariness and preference for solitude. Only the loneliness polygenic score significantly predicted the high trajectory for social wariness. By contrast, the general mental health genetic risk score factor was associated with the trajectory depicting high-chronic preference for solitude. CONCLUSIONS: Distinct associations were uncovered between the polygenic scores, social wariness, and preference for solitude.

Cohort Profile: Quebec Longitudinal Study of Child Development (QLSCD).

PURPOSE: The Quebec Longitudinal Study of Child Development (QLSCD) was designed to examine the long-term associations of preschool physical, cognitive, social, and emotional development with biopsychosocial development across childhood, adolescence, and young adulthood. METHODS: QLSCD is an ongoing prospective cohort including 2120 singletons born in 1997/1998 in the Canadian province of Quebec. So far, data have been collected annually or every 2 years from child ages 5 months to 21 years. The cohort currently includes 1245 participants. Data available include a range of environmental (e.g., family characteristics, child behaviour, educational attainment, mental health), biological (e.g., hair cortisol, genetic, epigenetic), and administrative data. RESULTS: QLSCD has contributed to the understanding of children's psychosocial development, including the development of physical aggression and anxiety. QLSCD articles have advanced scientific knowledge on the influence of early childhood factors on childhood, adolescent, and young adult mental health, including the effect of participation in early childcare on cognitive and behavioural development, the developmental origins of adolescent and young adult mental health problems and suicide risk, and the development of interpersonal difficulties (e.g., peer victimisation) from preschool years to adolescence. CONCLUSION: QLSCD has given major contributions to our understanding of the link between different aspects of child development and biopsychosocial development during the first two decades of life. Unique features include the presence of environmental, biological, and administrative data, long-term follow-up with frequent data collections, and use of data from multiple informants, including teachers, mothers, fathers, and the children themselves.

Depression and anxiety symptoms in young adults before and during the COVID-19 pandemic: evidence from a Canadian population-based cohort.

BACKGROUND: Concerns have been raised that the COVID-19 pandemic could increase risk for adverse mental health outcomes, especially in young adults, a vulnerable age group. We investigated changes in depression and anxiety symptoms (overall and severe) from before to during the pandemic, as well as whether these changes are linked to COVID-19-related stressors and pre-existing vulnerabilities in young adults followed in the context of a population-based cohort. METHOD: Participants (n = 1039) from the Quebec Longitudinal Study of Child Development reported on their depression (Centre for Epidemiological Studies Depression Scale, short form) and anxiety (General Anxiety Disorder-7 Scale) symptoms and completed a COVID-19 questionnaire during the first wave of the COVID-19 pandemic in the summer of 2020 (age 22 years). Assessments at age 20 (2018) were used to estimate pre-pandemic depression and anxiety symptom severity. RESULTS: While mean levels of depression and anxiety symptoms did not change from before to during the first wave of the COVID-19 pandemic (e.g., the mean of depressive symptoms was 9.30 in 2018 and 9.59 in 2020), we observed a slight increase in rates of severe depression (scores ≥ 21) from before (6.1%) to during (8.2%) the pandemic. Most COVID-19-related variables (e.g., loss of education/occupation, frequent news-seeking) - except living alone - and most pre-existing vulnerabilities (e.g., low SES, low social support) were not associated with changes in depression or anxiety symptoms. However, results varied as a function of pre-pandemic levels of depression and anxiety: depression and anxiety symptoms increased among adults with the lowest levels of symptoms before the pandemic, while they decreased among those with the highest levels of symptoms, possibly reflecting a regression to the mean. CONCLUSIONS: Depression and anxiety symptoms in young adults from Québec in Summer 2020 were mostly comparable to symptoms reported in 2018. Most COVID-19-related stressors and pre-existing vulnerabilities were not associated with changes in symptoms, except living alone and pre-existing symptoms of depression and anxiety. However, the increased rate of severe depression warrants further investigation.