This is part of a series about improving research, diagnosis and treatment. Join the conversation on Twitter with the hashtag #OpenMinds
It was by accident that Maddy Gilmore found relief through hurting herself. The B.C. girl was standing in the kitchen, twirling a steak knife between her fingers, when it slipped and cut her arm. The sight of her blood mesmerized her – so much so that she found herself shutting out all the anxious and negative thoughts whirring through her mind. She was 10 years old.
"I forgot everything I was thinking about and I was focused on that. And it was like, 'Oh, my brain turned off,' " says Gilmore, now 17, who has since been diagnosed with anxiety, obsessive-compulsive disorder and depression.
This discovery led her to cut herself intentionally whenever her thoughts spiralled out of control, first with steak knives, then with razor blades. When she reached high school, she discovered some of her friends were cutting themselves, too, but they never openly discussed the matter. Instead, Gilmore blogged about it on Tumblr.
"That, looking back, probably wasn't the best thing," she says. It connected her with other young people who were also struggling with mental-health issues, and together they shared their troubles and images of their self-inflicted wounds.
It's no coincidence that Gilmore's peers were also engaging in non-suicidal self-harm, which involves cutting, scratching or burning oneself as a way of responding to distress. The phenomenon has become alarmingly common among children and adolescents and, according to experts who study and treat it, often appears in clusters.
Those who deliberately hurt themselves tend to report having friends or online social networks who do it, too. Some researchers believe it can be socially contagious; hanging out with people who harm themselves may encourage some children to do the same.
It's unknown exactly how many individuals engage in non-suicidal self-injury. (Some U.S. studies have reported the behaviour in around 8 per cent of preteens and between 12 and 23 per cent of teens.) But Mitch Prinstein, a distinguished professor of psychology at the University of North Carolina at Chapel Hill, who studies adolescent self-injury, says it appears considerably more prevalent among children and young adults today than in previous generations.
While some people do it to provide physical evidence of their inner turmoil, others find the physical pain alleviates or provides distraction from their emotional pain. And although they don't do it with suicidal intent, people who engage in non-suicidal self-injury are more likely to contemplate or attempt suicide later, Prinstein says.
For Gilmore, the relief was temporary – she estimates she tried taking her own life about six times.
Prinstein, whose research focuses on the role of social influence on adolescent self-injury, suggests websites that discuss how to do it, similar to those that promote eating disorders, may be contributing to the spread of the behaviour. Certain celebrities have also been widely reported to have engaged in self-harm, including actress Angelina Jolie and comedian Russell Brand. And teens are also learning about self-harm from one another.
Knowing that others engage in the behaviour may increase the incidence, since teens are at a developmental stage that makes them particularly susceptible to peer influence, Prinstein says. But it's not just the act of self-harming that appears to be contagious. He says the feelings of anxiety and depression that prompt young people to hurt themselves may be socially transmitted as well.
Amanda Rose, a professor of psychological sciences at the University of Missouri, suggests "co-rumination," or the sharing of problems and negative thoughts, is to blame. She and other researchers have found growing evidence that co-rumination, especially among teenage girls, can undermine mental health.
Over time, friends feel closer to one another when they discuss their woes, but their depressive and anxiety symptoms also increase, Rose says.
Negative moods, she suggests, can be infectious, as co-rumination makes people dwell on their own troubles, thus making their problems seem bigger and more difficult to resolve. Exposure to friends' complaints also keeps them focused on negativity.
Girls are more vulnerable since they're socialized to talk about their problems, while boys are more often expected to keep their troubles and concerns to themselves, Rose says.
(Her research has found that as early as in elementary school, boys tend to think talking about their problems is a waste of time.)
The contagion effect seems to happen in two ways, she explains: "Kids who tend to be more depressed, they tend to have more in common and they kind of seek one another out … But then their [co-ruminating] behaviour sort of exacerbates the problem."
Not everyone is convinced these mental-health problems are transmissible. While being around others who are struggling can be detrimental to vulnerable individuals, peer influence does not actually cause mental illness, says Amy Cheung, a youth psychiatrist at Toronto's Sunnybrook Health Sciences Centre.
"If you had a healthy teenager," she says, "that teenager wouldn't suddenly start cutting because they saw it on Instagram."
Cheung advises that parents of children struggling with mental-health issues should take time to get to know their children's friends, to understand what's going on in their social lives, and to limit their access to websites and social media networks that promote self-injury, suicide or other harmful behaviours.
Rose suggests a little co-rumination is a good thing, but it's possible to go overboard. Instead of severing their children's ties to others who are struggling with mental-health problems, parents should work with the parents of their children's friends to maintain those relationships, she says. After all, she notes, loneliness and isolation are significant predictors of depression in young people.
But if she's right that negative emotions and behaviours can rub off among peers, it appears that positive ones can, too. Since seeking professional treatment, Gilmore, the B.C. teen who was engaging in self-harm, has started up a peer-support program at her school to help others with mental-health issues. Her enthusiasm is infectious – several other students have joined the effort.
In the process, Gilmore is improving her own mental health.
"Every time I share my experiences with mental health and mental illness," she says, "I get better each time."
The Centre for Addiction and Mental Health has purchased advertisements to accompany this series. The organization had no involvement in the creation or production of this, or any other, story in the series.