Researchers say that childhood bullying can lead to symptoms of anxiety, depression, and psychotic-like experiences, but that they seem to dissipate over time.
Between 1 in 3 and 1 in 4 students report having been bullied in a school environment in the United States.
Being the victim of bullying can have very serious consequences for a child's well-being and mental health, so understanding how this type of harassment affects children, as well as how lasting the effects are, is important in order to determine what kinds of interventions are necessary.
A team of researchers from various academic institutions in the United Kingdom - led by Dr. Jean-Baptiste Pingault, from University College London - set out to answer these two questions by analyzing data collected from a large cohort of twin children.
The researchers' findings were published earlier this week in JAMA Psychiatry.
Impact of bullying: Severe, but impermanent
Dr. Pingault and his team collected their data using the Twins Early Development Study, which is a large population study that used state records of births in England and Wales between 1994 and 1996.
All the data were collected between 2005 and 2013, and 11,108 twins were involved. On average, these were aged 11 at the time of their first assessment, and 16 years old when the last assessment was conducted.
The children were assessed for levels of anxiety, hyperactivity, impulsivity, and depression, as well as lack of attention, conduct problems, and psychotic-like experiences (paranoid or disorganized thoughts, for example) at age 11 and 16.
At ages 11 and 14, they were also assessed to determine whether or not they were experiencing bullying using the Multidimensional Peer-Victimization Scale.
Following their data analysis, the researchers confirmed that being bullied at a young age leads to symptoms of anxiety and depression, as well as to psychotic-like experiences. However, it was also noted that these effects lessened or completely disappeared over time.
For instance, symptoms of anxiety persisted for up to 2 years but were gone after 5 years. Paranoid and disorganized thoughts were longer-lasting but also tended to dissipate after the 5-year mark.
Dr. Pingault and his team studied pairs of twins because they hoped that any contrasts between the twins' mental health symptoms would allow them to use one twin as the "control" in each pair.
Thus, they explain, they would be able to account for any shared environmental and genetic factors that impacted the twins - especially monozygotic, or identical, twins - psychologically.
But the researchers also acknowledge that their study faced some limitations, not least of which the consideration that the "twin differences" design would not account for any confounding variables not shared between the siblings.
Also, Dr. Pingault and colleagues warn that there are some mental health outcomes that were not controlled for, and which may have longer-lasting effects.
Boosting resilience in children at risk
In their study paper, the researchers explain that due to their finding that such negative effects of bullying as anxiety do decrease or disappear over time, it may be helpful to consider working with children to improve their resilience to potential harassment from peers.
"Our finding that this direct contribution [of bullying to negative mental health outcomes] dissipated or reduced over time," the authors write, "highlights the potential for resilience in children exposed to bullying."
The researchers conclude that, in addition to primary interventions aimed at curbing bullying behavior in schools, it may be worth devising secondary interventions focused on resilience strategies for children at risk.
"In addition to primary prevention aiming to stop exposure to bullying, secondary preventive interventions in children exposed to bullying should address prior vulnerabilities, such as mental health difficulties, if we are to achieve a long-term impact on mental health."