Abstract
IMPORTANCE
Exposure to bullying is associated with poor mental health. However, the degree to which observed associations reflect direct detrimental contributions of exposure to bullying to mental health remains uncertain, as noncausal relationships may arise from genetic and environmental confounding (eg, preexisting vulnerabilities). Determining to what extent exposure to bullying contributes to mental health is an important concern, with implications for primary and secondary interventions.
OBJECTIVE
To characterize the concurrent and longitudinal contribution of exposure to
bullying to mental health in childhood and adolescence using a twin differences design to strengthen causal inference.
DESIGN, SETTING, AND PARTICIPANTS
Participants were drawn from the Twins Early Development Study, a population-based cohort recruited from population records of births in England and Wales between January 1, 1994, and December 31, 1996. Data collection took place when the participants were between 11 and 16 years of age from December 1, 2005, to January 31, 2013. Data analysis was conducted from January 1, 2016, to June 20, 2017.
EXPOSURES
Participants completed the Multidimensional Peer-Victimization Scale at 11 and
14 years of age.
MAIN OUTCOMES AND MEASURES
Mental health assessments at 11 and 16 years of age included anxiety, depression, hyperactivity and impulsivity, inattention, conduct problems,
and psychotic-like experiences (eg, paranoid thoughts or cognitive disorganization).
RESULTS
The 11 108 twins included in the final sample (5894 girls and 5214 boys) were a
mean age of 11.3 years at the first assessment and 16.3 years at the last assessment. The most stringent twin differences estimates (monozygotic) were consistent with causal contribution of exposure to bullying at 11 years to concurrent anxiety, depression, hyperactivity and impulsivity, inattention, and conduct problems. Effects decreased over time; that is, substantial concurrent contributions to anxiety (β = 0.27; 95%CI, 0.22-0.33) persisted for 2 years (β=0.12; 95%CI, 0.04-0.20) but not 5 years. Direct contributions to paranoid
thoughts and cognitive disorganization persisted for 5 years.
CONCLUSIONS AND RELEVANCE
This study is the largest to date to characterize the contribution of exposure to bullying in childhood to mental health using a twin differences design and multi-informant, multiscale data. Stringent evidence of the direct detrimental contribution of exposure to bullying in childhood to mental health is provided. Findings also suggest that childhood exposure to bullyingmay partly be viewed as a symptom of preexisting vulnerabilities. Finally, the dissipation of effects over time for many outcomes highlights the potential for resilience in children who were bullied. In addition to programs that aim to reduce exposure to bullying, interventions may benefit from addressing preexisting vulnerabilities and focus on resilience.
Exposure to bullying is associated with poor mental health. However, the degree to which observed associations reflect direct detrimental contributions of exposure to bullying to mental health remains uncertain, as noncausal relationships may arise from genetic and environmental confounding (eg, preexisting vulnerabilities). Determining to what extent exposure to bullying contributes to mental health is an important concern, with implications for primary and secondary interventions.
OBJECTIVE
To characterize the concurrent and longitudinal contribution of exposure to
bullying to mental health in childhood and adolescence using a twin differences design to strengthen causal inference.
DESIGN, SETTING, AND PARTICIPANTS
Participants were drawn from the Twins Early Development Study, a population-based cohort recruited from population records of births in England and Wales between January 1, 1994, and December 31, 1996. Data collection took place when the participants were between 11 and 16 years of age from December 1, 2005, to January 31, 2013. Data analysis was conducted from January 1, 2016, to June 20, 2017.
EXPOSURES
Participants completed the Multidimensional Peer-Victimization Scale at 11 and
14 years of age.
MAIN OUTCOMES AND MEASURES
Mental health assessments at 11 and 16 years of age included anxiety, depression, hyperactivity and impulsivity, inattention, conduct problems,
and psychotic-like experiences (eg, paranoid thoughts or cognitive disorganization).
RESULTS
The 11 108 twins included in the final sample (5894 girls and 5214 boys) were a
mean age of 11.3 years at the first assessment and 16.3 years at the last assessment. The most stringent twin differences estimates (monozygotic) were consistent with causal contribution of exposure to bullying at 11 years to concurrent anxiety, depression, hyperactivity and impulsivity, inattention, and conduct problems. Effects decreased over time; that is, substantial concurrent contributions to anxiety (β = 0.27; 95%CI, 0.22-0.33) persisted for 2 years (β=0.12; 95%CI, 0.04-0.20) but not 5 years. Direct contributions to paranoid
thoughts and cognitive disorganization persisted for 5 years.
CONCLUSIONS AND RELEVANCE
This study is the largest to date to characterize the contribution of exposure to bullying in childhood to mental health using a twin differences design and multi-informant, multiscale data. Stringent evidence of the direct detrimental contribution of exposure to bullying in childhood to mental health is provided. Findings also suggest that childhood exposure to bullyingmay partly be viewed as a symptom of preexisting vulnerabilities. Finally, the dissipation of effects over time for many outcomes highlights the potential for resilience in children who were bullied. In addition to programs that aim to reduce exposure to bullying, interventions may benefit from addressing preexisting vulnerabilities and focus on resilience.
| Original language | English |
|---|---|
| Journal | JAMA Psychiatry |
| Early online date | 4 Oct 2017 |
| DOIs | |
| Publication status | E-pub ahead of print - 4 Oct 2017 |
