The number of California teens who have been treated for self-harm has ballooned in recent years, with an especially concerning increase among multiracial girls, according to new research from the University of California, Berkeley, published today (Monday, April 14) in JAMA Pediatrics.
Using data from California emergency departments and inpatient care facilities from 2005 to 2021 — 231,232 reports in total — researchers examined both how the rate of annual nonfatal self-harm incidents has changed, as well as rate differences based on age, sex, and race and ethnicity.
The study found the overall self-harm rate among young people more than doubled, from 191 to 453 per 100,000 person-years — a public health metric used to track the incidence of disease or other life events. Researchers also found that nearly 73% of adolescents with treated self-harm injuries in California were girls.
White girls between 15 and 19 years old had the highest rate of self-harm in 2005 and have seen rates steadily increase since then. But multiracial adolescents have seen an increase of approximately 75% in self-harm rates since 2016. By 2021, self-harm rates were highest among multiracial teen girls, followed by those who are white.
Among boys, multiracial teens had the highest rates of self-harm and saw rates roughly double between 2016 and 2020. American Indian, white and Black boys saw rates increase, though not as dramatically.
"It's both the amount and also these increases that we're seeing over time that are most concerning," said Emily Liu, a Ph.D. candidate at UC Berkeley's School of Public Health and first author of the research.
While prior work has found that girls are at higher risk of self-harm than boys, Liu's research shows incidences of self-harm are not universal across demographics.
"It's important to look at the data not just by sex, not just by age, not just by race or ethnicity, but by the intersection of all of these three things. It really does highlight the differences," Liu said. "The rates are rising, and we really need to pay attention to multiracial adolescents."
Researchers expected a dip in self-harm cases treated at hospitals in 2020 and 2021, when people may have avoided health care facilities due to the raging COVID-19 pandemic. Yet, the incidences still rocketed up, according to the analysis.
"If anything, it's a bit of an undercount for those two years," said Jennifer Ahern, a professor of epidemiology at UC Berkeley's School of Public Health and senior author of the research. "We know that this mental health crisis is not itself news. But self-harm injuries are very concrete physical manifestations of that crisis."
"This is really on the rise," she added, "and we would want clinicians to be prepared to help these children when they are appearing for care."
Much has been written about what's driving the teen mental health crisis. Cell phones and social media are often seen as a main culprit, though researchers differ on how much blame devices and apps deserve. Better documentation practices at hospitals and a decrease in social stigma about seeking mental health help are also thought by some to have driven some of the increases in self-harm reports.
Explaining what is driving the increase was beyond the scope of the new research, Liu said.
Liu and her colleagues from UC Berkeley, New York University and the University of Minnesota conducted their analysis late last year and felt compelled to call attention to the work in a major journal as soon as possible. They announced their findings today as a relatively brief research letter, as opposed to waiting to publish a longer academic article, with the intent of drawing the attention of medical practitioners and those who work with adolescents.
"This is an urgent issue that they need to pay attention to, "Liu said. "They should be prepared to be able to address health self-harm when it presents and also to think about ways to prevent it."
