A study out this week suggests that the release of the first season of Netflix's 13 Reasons Why series in 2017 led to a small but notable uptick in teen suicides. The finding seems to confirm widespread apprehensions among mental health experts and advocates that a suicide "contagion" could spread from the teen drama, which centers around a 17-year-old girl's suicide and includes graphic details. But the study contains significant caveats, and the findings should be interpreted cautiously.

The study was published online by the Journal of the American Academy of Child & Adolescent Psychiatry and conducted by a research team led by epidemiologist Jeff Bridge at Nationwide Children's Hospital in Columbus, Ohio. The researchers analyzed monthly suicide rates in the four years prior to the show's March 31, 2017 release, plus post-release suicide rates through December 31, 2017.

The researchers concluded that in the month following the show's initial release in April 2017, there was a 28.9 percent increase in suicides among 10- to 17-year-olds that would not have otherwise been predicted. They also found elevated rates in June and December of 2017, which they attributed to the show as well.

"In conclusion, we found a significant increase in suicide rates among US children and adolescents in the month after the release of 13 Reasons Why," the researchers wrote. "Suicide rates in two subsequent months remained elevated over forecasted rates, resulting in 195 additional deaths."

In a press statement, co-author Lisa Horowitz, a clinical scientist at the National Institute of Mental Health, said that the finding "should raise awareness that young people are particularly vulnerable to the media. All disciplines, including the media, need to take good care to be constructive and thoughtful about topics that intersect with public health crises."

While the point that care should be taken with regard to suicide should be duly noted, it's still unclear just how vulnerable young people are to the show's content. The study has significant caveats and limitations. And the overall field of research into the epidemiology of suicide is a bit murky.

Study caveats

First and foremost, the new study is correlational; it cannot prove that any statistically significant changes in suicide rate found in the post-release time frame of the study were caused by the show. And speaking of statistical significance, the study used a quasi-experimental forecasting model to make predictions about what suicide rates should have been after the show's release. This method tried to account for seasonal patterns and other underlying trends. But the initial analysis indicated that the data was too variable for other statistical models (a problem called as overdispersion), which is a known sticking point when looking at such small numbers of suicides.

As Harvard psychologist Matthew K. Nock noted in an interview with The New York Times, "Suicide rates bounce around a lot more when the cell sizes are low, as they are with kids aged 10 to 17 years. So, this new paper suggests there may be an association between 13 Reasons Why and the suicide rate. However, we must always be cautious when trying to draw causal conclusions from correlational data."

In terms of bouncing around, the authors reported finding a significant uptick in suicides in April—the month after the show's release—but they also found them in June and December. It's unclear how the show is linked to changes in those specific months. Moreover, the authors found a statistically significant increase in suicides in a fourth month—the month of March, which would be prior to the show's release on March 31. The authors say this finding "raises questions about effects of pre-release media promotion of the series premiere." However, it also raises questions about whether factors or events unrelated to the show may explain or contribute to the reported increase in suicide rates.

All in all, the researchers estimated that between April 1 and December 31 of 2017, there were 195 additional suicide deaths that would not otherwise have been predicted following the release of 13 Reasons Why. Of those 195 deaths, 58 were linked to April and the other 137 were from June and December.

Another odd wrinkle emerged from the data when the authors looked at the sex breakdown of those deaths. The statistically significant increase in suicides was entirely due to suicides in boys, not girls, as the researchers had hypothesized. This was surprising to the researchers because the main character who commits suicide in 13 Reasons Why is a 17-year-old girl. As such, they expected the suicide to resonate most with female viewers in that age range. However, there was no statistically significant change in the suicide rates of 10- to 17-year-old girls in the study's time frame, and there was no change in older age groups, regardless of sex.

Missing data

The sex finding flies in the face of some ideas of a "suicide contagion," a term used by the authors of the new study and used generally by researchers to discuss the hypothetical contagiousness of suicide from events or media. Often (not always), when epidemiologists toss around the term, they do so with the idea that those who are vulnerable to suicide after being exposed (directly or indirectly) to a suicide or suicide attempt are those who strongly identify somehow with the person or character who committed suicide or attempted to do so. Based on the data in the study, that does not appear to be the case here.

But that discrepancy may simply be due to the fact that we only have data on suicides, not non-fatal suicide attempts. Researchers have established that males tend to have higher rates of suicide, and females have higher rates of suicide attempts. Thus, it could be that a jump in suicide attempts in girls and teens following the show was simply not captured in the data. We don't know. The study authors report that monthly data on suicide attempts was not available.

There's also no data on the methods of suicides, which would be helpful in assessing another idea linked to "suicide contagion," one that deals with imitation or copycat suicides—a phenomenon known as the Werther Effect. Some researchers would hypothesize that if viewing 13 Reasons Why encouraged vulnerable viewers to act on suicidal impulses, they may do so using the same suicide method. The idea stems from the 1770s, when some readers of the German novel The Sorrows of Young Werther committed suicide in the same manner of the main character.

Contagiousness?

Another critical bit of data missing from the study is viewership. We don't know if those who committed suicide even watched the show—let alone if they watched all or just some of it, which may be most telling. In a study published late last month, an international team of researchers found that people who watched just part of the second season of 13 Reasons Why were at greater risk of suicide than those who stuck through and watched the whole season (all based on self-reported survey data). The authors speculated that the findings suggest that there are self-selecting groups of people who are interested and begin watching. Some viewers are perhaps distressed by the content and stop watching, while others continue on and may benefit, such as by increasing compassion for those who are suicidal or learning from the show how to identify and help a suicidal person.

"Apparently, there is no one-size-fits-all solution to suicide prevention in fictional suicide depictions," write the authors of the study, which was published in the journal Social Science and Medicine. "It appears that audiences relate differently to such content depending on their backgrounds and viewing patterns."

Overall, the research into 13 Reasons Why serves to highlight the complexity of suicide and suicide prevention—and also the murkiness of the research field that surrounds it.

In a 2014 review of how social scientists discuss and study the spread of suicide in populations, experts in suicide prevention came up flummoxed. They found a "remarkable lack of clarity and inconsistent definition of 'contagion,'" which allowed researchers "to cite one another to support their arguments without having to delve into the differences that separate them."

They conclude:

Many authors have adopted the term as an analogy, with complex implications regarding shared characteristics and presumed mechanisms of spread that have scant scientific support. Once adopted, contagion has been oft-repeated without critical scrutiny of its uncertain meanings, or implied mechanisms, and the presumed clarity of what authors have intended to say has only served to mask or mute rigorous inquiry. Based on current data and appreciating the substantial limitations in published studies that we have described, it is problematic to draw any conclusion whether suicide truly is contagious–that is, passed from one person to another, either directly or indirectly. Undoubtedly, clusters are apparent and well described, and population-level fluctuations have been demonstrated after key events. These do not prove contagion! Our review suggests that the concept of suicide contagion requires further investigation, and its use (along with terms such as epidemic) should be defined cautiously and thoughtfully.

If you or someone you know is feeling suicidal or in distress, please call the Suicide Prevention Lifeline number, 1-800-273-TALK (8255), which will put you in touch with a local crisis center.