Noradrenaline (NE) plays an integral role in shaping behavioral outcomes including anxiety/depres... more Noradrenaline (NE) plays an integral role in shaping behavioral outcomes including anxiety/depression, fear, learning and memory, attention and shifting behavior, sleep-wake state, pain, and addiction. However, it is unclear whether dysregulation of NE release is a cause or a consequence of maladaptive orientations of these behaviors, many of which associated with psychiatric disorders. To address this question, we used a unique genetic model in which the brain-specific Vesicular Monoamine Transporter-2 (VMAT2) gene expression was removed in NE-positive neurons disabling NE release in the entire brain. We engineered VMAT2 gene splicing and NE depletion by crossing floxed VMAT2 mice with mice expressing the Cre-recombinase under the DBH gene promotor. In this study, we performed a comprehensive behavioral and transcriptomic characterization of the VMAT2DBHcre KO mice to evaluate the role of central NE in behavioral modulations. We demonstrated that NE depletion induces anxiolytic and...
Background: Prior studies indicate that peer victimization (including bullying) is associated wit... more Background: Prior studies indicate that peer victimization (including bullying) is associated with higher risk for depression and suicidal ideation across the life course. However, molecular mechanisms underlying these associations remain unclear. This two-cohort study proposes to test whether epigenetic aging and pace of aging, as well as a DNA methylation marker of responsive to glucocorticoids, are associated to childhood peer victimization and later depressive symptoms, or suicidal ideation.Methods: Cohort 1: Epigenome-wide DNA methylation (EPIC array) was measured in saliva collected when participants were 10.47 years (standard deviation = 0.35) in a subsample of the Quebec Longitudinal Study of Child Development (QLSCD, n = 149 participants), with self-reported peer victimization at 6–8 years, depressive symptoms (mean symptoms, and dichotomized top 30% symptoms) and suicidal ideation at 15–17 years. Cohort 2: Epigenome-wide DNA methylation (EPIC array) was measured in blood c...
BACKGROUND Peer victimization is associated with an increased risk for depression, but there is l... more BACKGROUND Peer victimization is associated with an increased risk for depression, but there is less evidence on how certain factors such as friend support can buffer this association. This study investigated the associations between friend support and depressive symptoms among victimized and non-victimized adolescent girls and boys from South Korea. METHODS Participants includes 2258 students from the Korean Children and Youth Panel Survey, a nationally representative sample of middle school students in South Korea. Self-reported perceived friend support, depressive symptoms and peer victimization were measured using validated scales during middle school year 3 (mean age= 15.7 years). RESULTS The association between peer victimization and depressive symptoms varied by sex (p for sex by peer victimization interaction<0.05). Peer victimization was more strongly associated with same year depressive symptoms in girls (β=0.55) than boys (β=0.24). After controlling for key confounders, including prior year mental health symptoms, higher levels of friend support were found to attenuate the association between peer victimization and depressive symptoms (p for friend support by peer victimization interaction <0.05). Peer victimization was associated with more depressive symptoms for adolescents with low and moderate friend support, but not those with high friend support. LIMITATIONS Peer victimization, depressive symptoms, and friend support, were self-reported and measured the same year. CONCLUSIONS Friend support protects victimized South Korean adolescents from the negative effect of peer victimization on depressive symptoms, hence contributes to closing the gap in depression between victimized and non-victimized adolescents.
Journal of psychiatry & neuroscience : JPN, Jan 27, 2015
The monoaminergic transmitters dopamine (DA), noradrenaline (NE) and serotonin (5-HT) modulate ce... more The monoaminergic transmitters dopamine (DA), noradrenaline (NE) and serotonin (5-HT) modulate cerebral functions via their extensive effects in the brain. Investigating their roles has led to the creation of vesicular monoaminergic transporter-2 (VMAT2) knockout (KO) mice. While this mutation results in postnatal death, VMAT2-heterozygous (HET) mice are viable and show a complex behavioural phenotype. However, the simultaneous alteration of the 3 systems prevents investigations into their individual functions. To assess the specific role of NE, 5-HT and DA, we genetically disrupted their neurotransmission by creating conditional VMAT2-KO mice with targeted recombination. These specific recombinations were obtained by breeding VMAT2lox/lox mice with DBHcre, SERTcre and DATcre mice, respectively. We conducted a complete neurochemical and behavioural characterization of VMAT2-HET animals in each system. Conditional VMAT2-KO mice revealed an absence of VMAT2 expression, and a specific ...
BackgroundSuicide is a leading cause of mortality in youth, yet the course of suicide attempts is... more BackgroundSuicide is a leading cause of mortality in youth, yet the course of suicide attempts is poorly documented. We explored the vulnerable transition from adolescence to emerging adulthood to identify group trajectories and risk factors.MethodsThe National Longitudinal Survey of Children and Youth is a prospective representative cohort of Canadian children. We followed participants aged 7–11 years in 1994–95 to age 23 (2008–09). We modelled self-reported past-year suicide attempts (ages 12 to 23 years) using growth mixture models. We analysed risk factors from self- and parent-report questionnaires at pre-adolescence (ages 10–11) and early adolescence (ages 12–13) using multinomial logistic regressions. Analyses were adjusted for sample non-response and attrition.ResultsIn 2233 participants answering questions on teen and adult suicide attempts, we identified three trajectories: never attempted (96.0%), adolescence-limited (2.0%) and persisting into adulthood (2.0%). Adolescent...
CMAJ : Canadian Medical Association journal = journal de l'Association medicale canadienne, Jan 15, 2018
Exposure to peer victimization is relatively common. However, little is known about its developme... more Exposure to peer victimization is relatively common. However, little is known about its developmental course and its effect on impairment associated with mental illnesses. We aimed to identify groups of children following differential trajectories of peer victimization from ages 6 to 13 years and to examine predictive associations of these trajectories with mental health in adolescence. Participants were members of the Quebec Longitudinal Study of Child Development, a prospective cohort of 2120 children born in 1997/98 who were followed until age 15 years. We included 1363 participants with self-reported victimization from ages 6 to 13 years and data available on their mental health status at 15 years. We identified 3 trajectories of peer victimization. The 2 prevailing groups were participants with little or moderate exposure to victimization (441/1685 [26.2%] and 1000/1685 [59.3%], respectively); the third group (244 [14.5%]) had been chronically exposed to the most severe and lon...
Noradrenaline (NE) plays an integral role in shaping behavioral outcomes including anxiety/depres... more Noradrenaline (NE) plays an integral role in shaping behavioral outcomes including anxiety/depression, fear, learning and memory, attention and shifting behavior, sleep-wake state, pain, and addiction. However, it is unclear whether dysregulation of NE release is a cause or a consequence of maladaptive orientations of these behaviors, many of which associated with psychiatric disorders. To address this question, we used a unique genetic model in which the brain-specific Vesicular Monoamine Transporter-2 (VMAT2) gene expression was removed in NE-positive neurons disabling NE release in the entire brain. We engineered VMAT2 gene splicing and NE depletion by crossing floxed VMAT2 mice with mice expressing the Cre-recombinase under the DBH gene promotor. In this study, we performed a comprehensive behavioral and transcriptomic characterization of the VMAT2DBHcre KO mice to evaluate the role of central NE in behavioral modulations. We demonstrated that NE depletion induces anxiolytic and...
Background: Prior studies indicate that peer victimization (including bullying) is associated wit... more Background: Prior studies indicate that peer victimization (including bullying) is associated with higher risk for depression and suicidal ideation across the life course. However, molecular mechanisms underlying these associations remain unclear. This two-cohort study proposes to test whether epigenetic aging and pace of aging, as well as a DNA methylation marker of responsive to glucocorticoids, are associated to childhood peer victimization and later depressive symptoms, or suicidal ideation.Methods: Cohort 1: Epigenome-wide DNA methylation (EPIC array) was measured in saliva collected when participants were 10.47 years (standard deviation = 0.35) in a subsample of the Quebec Longitudinal Study of Child Development (QLSCD, n = 149 participants), with self-reported peer victimization at 6–8 years, depressive symptoms (mean symptoms, and dichotomized top 30% symptoms) and suicidal ideation at 15–17 years. Cohort 2: Epigenome-wide DNA methylation (EPIC array) was measured in blood c...
BACKGROUND Peer victimization is associated with an increased risk for depression, but there is l... more BACKGROUND Peer victimization is associated with an increased risk for depression, but there is less evidence on how certain factors such as friend support can buffer this association. This study investigated the associations between friend support and depressive symptoms among victimized and non-victimized adolescent girls and boys from South Korea. METHODS Participants includes 2258 students from the Korean Children and Youth Panel Survey, a nationally representative sample of middle school students in South Korea. Self-reported perceived friend support, depressive symptoms and peer victimization were measured using validated scales during middle school year 3 (mean age= 15.7 years). RESULTS The association between peer victimization and depressive symptoms varied by sex (p for sex by peer victimization interaction<0.05). Peer victimization was more strongly associated with same year depressive symptoms in girls (β=0.55) than boys (β=0.24). After controlling for key confounders, including prior year mental health symptoms, higher levels of friend support were found to attenuate the association between peer victimization and depressive symptoms (p for friend support by peer victimization interaction <0.05). Peer victimization was associated with more depressive symptoms for adolescents with low and moderate friend support, but not those with high friend support. LIMITATIONS Peer victimization, depressive symptoms, and friend support, were self-reported and measured the same year. CONCLUSIONS Friend support protects victimized South Korean adolescents from the negative effect of peer victimization on depressive symptoms, hence contributes to closing the gap in depression between victimized and non-victimized adolescents.
Journal of psychiatry & neuroscience : JPN, Jan 27, 2015
The monoaminergic transmitters dopamine (DA), noradrenaline (NE) and serotonin (5-HT) modulate ce... more The monoaminergic transmitters dopamine (DA), noradrenaline (NE) and serotonin (5-HT) modulate cerebral functions via their extensive effects in the brain. Investigating their roles has led to the creation of vesicular monoaminergic transporter-2 (VMAT2) knockout (KO) mice. While this mutation results in postnatal death, VMAT2-heterozygous (HET) mice are viable and show a complex behavioural phenotype. However, the simultaneous alteration of the 3 systems prevents investigations into their individual functions. To assess the specific role of NE, 5-HT and DA, we genetically disrupted their neurotransmission by creating conditional VMAT2-KO mice with targeted recombination. These specific recombinations were obtained by breeding VMAT2lox/lox mice with DBHcre, SERTcre and DATcre mice, respectively. We conducted a complete neurochemical and behavioural characterization of VMAT2-HET animals in each system. Conditional VMAT2-KO mice revealed an absence of VMAT2 expression, and a specific ...
BackgroundSuicide is a leading cause of mortality in youth, yet the course of suicide attempts is... more BackgroundSuicide is a leading cause of mortality in youth, yet the course of suicide attempts is poorly documented. We explored the vulnerable transition from adolescence to emerging adulthood to identify group trajectories and risk factors.MethodsThe National Longitudinal Survey of Children and Youth is a prospective representative cohort of Canadian children. We followed participants aged 7–11 years in 1994–95 to age 23 (2008–09). We modelled self-reported past-year suicide attempts (ages 12 to 23 years) using growth mixture models. We analysed risk factors from self- and parent-report questionnaires at pre-adolescence (ages 10–11) and early adolescence (ages 12–13) using multinomial logistic regressions. Analyses were adjusted for sample non-response and attrition.ResultsIn 2233 participants answering questions on teen and adult suicide attempts, we identified three trajectories: never attempted (96.0%), adolescence-limited (2.0%) and persisting into adulthood (2.0%). Adolescent...
CMAJ : Canadian Medical Association journal = journal de l'Association medicale canadienne, Jan 15, 2018
Exposure to peer victimization is relatively common. However, little is known about its developme... more Exposure to peer victimization is relatively common. However, little is known about its developmental course and its effect on impairment associated with mental illnesses. We aimed to identify groups of children following differential trajectories of peer victimization from ages 6 to 13 years and to examine predictive associations of these trajectories with mental health in adolescence. Participants were members of the Quebec Longitudinal Study of Child Development, a prospective cohort of 2120 children born in 1997/98 who were followed until age 15 years. We included 1363 participants with self-reported victimization from ages 6 to 13 years and data available on their mental health status at 15 years. We identified 3 trajectories of peer victimization. The 2 prevailing groups were participants with little or moderate exposure to victimization (441/1685 [26.2%] and 1000/1685 [59.3%], respectively); the third group (244 [14.5%]) had been chronically exposed to the most severe and lon...
Uploads
Papers by Léa Perret