Self-harm — physically harming yourself — is common among young people, affecting around one in five teenagers by the age of 18.
Only about one in eight episodes of self-harm in teenagers is seen in hospital emergency departments. However, hospitalization for self-harm is one of the strongest risk factors for future suicide.
In a newly published study, experts identified some of the risk factors for self-harm by combining information from hospital assessments with other sources of information, such as school attendance, special educational needs, and the status of free school meals. Bringing together sources of information related to the same person in this way is called data linking. It is a powerful tool to maximize the value of public health data.
Girls are at higher risk
Self-harm refers to any act of self-harm performed by a person, regardless of their motivation. This usually involves self-poisoning with drugs or self-injury by cutting.
The new study showed that boys with autism spectrum disorder (ASD) had a nearly three times higher risk of self-harm than boys without. ASD was not a significant risk of self-harm in girls, although this may be due to underdiagnosis of ASD in girls.
In general, however, the risk of self-harm was higher among girls (1.5 percent) than boys (0.3 percent), consistent with previous research.
Although evidence suggests that ASD is a risk factor for self-harm in adults, much less research has been done on risk in teenagers. Existing research often involves small, selective studies that use clinical samples rather than whole population samples.
In contrast, data linkage allowed experts to study a vast amount of information. They analyzed data from over 113,000 young people aged 11 to 17 from four boroughs in south London, collected between 2009 and 2013. The findings about an increased risk of self-harm in boys with ASD are therefore important in order to fill this research gap.
They also found that attention deficit hyperactivity disorder (ADHD) was a strong predictor of self-harm in both boys and girls. Young people with ADHD were about four times more likely to self-harm than those without ADHD.
Adolescents who had previously attended mental health services for ADHD were four times more likely to harm themselves than those who had not attended services for ADHD. These are important findings because of an evidence gap: there are very few UK studies that have examined the link between ADHD and self-harm, particularly in girls.
Socioeconomic risk factors
Researchers also discovered that young people who spend time outside of school, either through exclusion or absenteeism, were at greater risk of self-harm. Those with less than 80 percent participation were three times more likely to harm themselves than those with more than 80 percent participation.
These results do not show that absenteeism leads to self-harm. However, they point out that this is an important group of young people that preventive interventions should target.
Previous research examining socioeconomic risk factors for self-harm has shown that girls who are granted free school lunch status are also significantly more likely to commit self-harm. It has also been shown that children in care are exposed to an increased risk.
The research also led to some unexpected findings. English as a second language appeared to act as a protective factor for self-harm. However, this may be due to the fact that young people with English as a second language may not present themselves to mental health services. Previous research has found that language barriers are an important contributor to inequalities in access to services.
Furthermore, although there were associations between free school food status and self-harm, the experts found no association between neighborhood deprivation and self-harm. Although at odds with previous research, the findings support more recent research showing that some deprived inner-city areas, such as parts of London, have lower rates of self-harm.
Factors that could explain this include, on the one hand, community solidarity and what researchers have termed a culture of self-reliance, and on the other hand, the collective feeling that being identified as mentally ill is risky – and that it is as is the case with mental health services, it is intrusive and compulsive.
Data linking enables the study of entire populations. It’s less intrusive than asking people to fill out surveys. It allows research to include people who may not be proactive participants in traditional studies. Researchers were also able to examine the risk factors behind self-harm in young people and identify the groups that may be most vulnerable.
These results are an important step in developing strategies to prevent self-harm and demonstrate the power of data linkage to address public health problems.
May 01, 2022