The Evolving Science Of How Childhood Trauma Shapes Adults

FLORA LICHTMAN: This is Science Friday. I’m Flora Lichtman. Just a heads up that our next conversation covers a sensitive subject, trauma. We know that the experiences from our childhood, the good and the bad, shape who we become as adults. But understanding what kinds of early experiences have staying power into adulthood and the wide range of impacts they can have is an emerging science.

Here to tell us more is Preeti Simran Sethi, a science writer and Rosalynn Carter Mental Health Journalism fellow, who’s been reporting on Asian mental health. Preeti, welcome to Science Friday.

PREETI SIMRAN SETHI: Thank you, Flora.

FLORA LICHTMAN: So today, we’re talking about studying the effects of negative childhood experiences. Basically, trying to understand the impact of childhood trauma. When did people start digging into this question scientifically, like, trying to understand it on a population level?

PREETI SIMRAN SETHI: Well, I mean, back in the 19th century, scholars like Freud theorized about the impacts of childhood trauma on adults, but it wasn’t studied in large groups of people until the 1980s. And the first researchers to do so didn’t set out to study childhood trauma at all. They were actually studying obesity.

Back in 1980, a doctor in San Diego named Vincent Felitti, who was chief of the Department of Preventative Medicine at one of America’s biggest health care companies, started a clinic to help people lose weight. And it really took off. But then this strange thing kept happening. Patients would successfully lose weight, and then–

CHRISTINE FORKE: They were finding this really unusual trend where women who were losing a consistent amount of weight and actually were doing really well in terms of the intervention, were often the ones who were dropping out of the study and were then gaining the weight back.

PREETI SIMRAN SETHI: That’s Christine Forke, an assistant professor of family medicine and community health in the Perelman School of Medicine at the University of Pennsylvania. So Felitti dug in to try to understand what was going on. And as he was talking to patients, a few shared that they had been sexually abused, and they thought those experiences might be tied to their weight gain.

So the clinic decided to ask all incoming patients if they’d had a history of sexual trauma. And the response was what Felitti describes as overwhelming.

FLORA LICHTMAN: What do you mean?

PREETI SIMRAN SETHI: Over half of the nearly 300 patients he and his colleagues interviewed had experienced childhood sexual trauma. And for context, Flora 1 in 4 girls and 1 in 20 boys in the United States are estimated to have experienced childhood sexual abuse. Those are staggering statistics.

FLORA LICHTMAN: Yeah.

PREETI SIMRAN SETHI: Felitti started to think about what happened to his patients as kids and how it was still having an impact. And he shared those insights at an obesity conference in Atlanta in 1990. A scientist from the CDC who heard the presentation was like, these findings are potentially groundbreaking, but you need to broaden the study, not just obesity patients, do this with a broader population.

And so Felitti and his colleagues did just that. Over the span of two years in the mid ’90s, they interviewed thousands and thousands of patients going through health assessments at Kaiser Permanente. And they asked them 10 yes or no questions. Here’s Christine again.

CHRISTINE FORKE: And those items include things like sexual abuse, physical abuse, emotional abuse, physical and emotional neglect, as well as items that we would consider household dysfunction, like living with a parent who has a mental illness or has been incarcerated, using substances, things like that.

PREETI SIMRAN SETHI: It’s hard to conceive of this now, Flora, but up until the Felitti study, connections around how profoundly maltreatment when we’re kids can impact us later in life hadn’t been made in any systematic way.

FLORA LICHTMAN: So what did what did researchers take away from this study?

PREETI SIMRAN SETHI: Well, first, it showed childhood traumas, what the researchers called adverse childhood experiences, are correlated with a wide range of physical and mental health issues. And just as important, the study highlighted how many folks have experienced childhood trauma.

The researchers had listed 10 adverse childhood experiences, and the majority of adults surveyed said they had experienced at least one. About 17% of folks said they’d experienced 4 or more of the 10.

FLORA LICHTMAN: OK, wow. So a lot of people have had these experiences. In this study, did they find these experiences correlated to any impacts in adulthood?

PREETI SIMRAN SETHI: They did. That initial analysis showed adults who experienced four or more of those traumas as kids were twice as likely to develop heart disease, three times more likely to have clinical depression, five times more likely to develop an addiction to alcohol, and 17 times more likely to attempt suicide. It’s what researchers call a dose response. The more adverse experiences you have, the more likely you are to have a whole range of health issues.

FLORA LICHTMAN: Wow. I mean, that’s really shocking. And no one had ever measured this before?

PREETI SIMRAN SETHI: Nope.

FLORA LICHTMAN: To me, it’s kind of crazy that an obesity doctor kind of randomly stumbled into this finding that opened up this new field of clinical study.

PREETI SIMRAN SETHI: It is. And what I shared just isn’t even the full list. Later studies have shown a higher number of childhood traumas increased chances of chronic lung in liver disease and certain cancers, plus increased levels of PTSD, sexually transmitted infections, homelessness, incarceration, criminal behaviors, relationship challenges, and a shortened lifespan.

FLORA LICHTMAN: All right. So obviously, these are all just correlations. How well do scientists understand the how, the mechanism of how these childhood experiences might lead to these outcomes?

PREETI SIMRAN SETHI: Well, researchers are trying to build on that foundational research, first and foremost to understand just that, what are the mechanisms. But the work is also being used to inform public policy and somewhat controversially, as a diagnostic tool in clinical settings.

FLORA LICHTMAN: Wait, why is it controversial?

PREETI SIMRAN SETHI: Well, doctors and therapists ask their patients to fill out the Adverse Childhood Experiences Survey as part of intake. Some do. California has actually launched an initiative to encourage it, but Felitti’s co-collaborator in the original study, Robert Anda, and others have argued that the Adverse Childhood Experiences Survey isn’t standardized and was never meant to be used to diagnose or screen folks for future risk.

Leading researchers in childhood trauma told me that it doesn’t make sense to overload the health care system by assessing a bunch of people for trauma without any way to alleviate it. Until psychologists can develop effective interventions for the childhood harms, they identify and ensure the people who have experienced those traumas have proper support, they say it’s better to focus on building up the data set to understand more clearly how traumatic events in childhood linked to adverse impacts in adulthood. And to develop policies and other interventions that, hopefully, will keep those traumas from happening in the first place.

FLORA LICHTMAN: So what do we still need to learn? What did we not get from the initial study?

PREETI SIMRAN SETHI: That first Felitti study was big and really, was groundbreaking, but it drew from a pretty homogeneous group. Here’s Christine again.

CHRISTINE FORKE: This was done on the West Coast, and it was primarily White participants, middle class, insured, highly educated. And they also were coming to seek medical care.

FLORA LICHTMAN: OK. Gotcha. I mean, we know that leaning on one demographic is a pervasive problem in science and medicine, generally. Women are underrepresented in clinical trials, and so dosing is, in many cases, based on male bodies.

PREETI SIMRAN SETHI: Exactly. And beyond gender, the majority of psychological research is done within what are known as WEIRD populations. WEIRD is an acronym that stands for people who come from Western, educated, industrialized, rich, and democratic countries.

One study showed that less than 3% of folks who participate in psychological studies are from Africa, Asia, Central and South America, or the Middle East. But I mean, those are the people who make up the majority of the global population.

And another stat that really stood out to me was that an American undergraduate student is 4,000 times more likely to be selected as a subject for research than a non-Westerner. And that’s a problem because research done on Westerners is often assumed to be universal, which really overlooks important differences in cultures, histories, and life experiences.

FLORA LICHTMAN: And it seems like there are a ton of variables between person to person, including people’s life experiences, which aren’t easily captured on a 10-question survey.

PREETI SIMRAN SETHI: Yeah, I’m going to get personal for a minute here, if that’s OK.

FLORA LICHTMAN: Please do.

PREETI SIMRAN SETHI: A couple of years ago, I was given the Adverse Childhood Experiences Survey, that original one Felitti and his colleagues developed. That’s still used more than any other survey. Those 10 questions, remember, focus on physical and emotional neglect or harm, sexual violence, substance abuse, the incarceration of a family member, or the separation or divorce of a parent.

Now, by that assessment, I looked pretty OK, but there were all these other things that had happened to me as a kid. Being an immigrant, having to learn American culture, and dealing with racism and xenophobia, feeling the financial stressors that my parents were under. That did have an impact, but they weren’t even named.

In the population Felitti and his team were working with– mostly White, mostly well-off, insured– those issues didn’t come up, but in other settings, it did. In other people, it does. Christine Forke and her colleague, Peter Cronholm, who’s a professor of family medicine at the University of Pennsylvania, headed up a research team that took a different, more expansive approach to assessing childhood traumas.

FLORA LICHTMAN: How do you mean?

PREETI SIMRAN SETHI: Well, for starters, instead of interviewing adults, they surveyed a racially and socioeconomically diverse group of young people. And they expanded the types of traumas included in the survey. Here’s Peter.

PETER CRONHOLM: We had decided to try to measure things related to witnessing community violence, living in unsafe neighborhoods, the experience of bullying or discrimination, and experience with the foster care system.

FLORA LICHTMAN: So what did they find?

PREETI SIMRAN SETHI: One big finding is that different kinds of traumas are linked to different kinds of health outcomes. For example, some of the additional challenging childhood experiences that they added tended to be associated with at-risk behaviors and mental health, rather than physical health.

The expanded list also offered new insights into the repercussions of experiences that weren’t part of that original study, like bullying. Researchers now know bullying can have effects equivalent to maltreatment by a parent. But in the mid 1980s, they didn’t know that.

So for the questions that are asked matter. And when you’re studying trauma, how the questions are asked also matters. Let me give you an example I heard from psychologist Shin Shin Tang, who wrote the book Asian-American Psychology and Psychotherapy. She uses the term ACEs to reference adverse childhood experiences.

SHIN SHIN TANG: Some ACEs, like child abuse and neglect, are incredibly high among Asian-American communities. We’re talking figures upwards of 80% of the population, and yet, the opposite message keeps getting repeated. So this, to me, is a fascinating case study of racial bias in research and finding what we expect to see.

So what I mean is that there’s this stereotype of Asian Americans as being successful and not having problems. Even despite the fact that we have large-scale studies that say rates of abuse and neglect are actually quite high among Asian-Americans.

PREETI SIMRAN SETHI: I asked her why there was such a disconnect.

SHIN SHIN TANG: So it turns out some of the few studies that indicate low rates of ACEs relied largely on cases of abuse being reported to authorities, like a medical provider or a child protective services. Or in some cases, the research asks parents if their children have experienced abuse.

But when it comes to Asian Americans relying on these kinds of reports, it’s extremely faulty because Asian Americans are the least likely to report things to authorities. And it ignores cultural values, like the need to preserve space and a reluctance to disclose trouble in the family.

PREETI SIMRAN SETHI: If you don’t ask appropriate questions in a culturally sensitive way, you get these pervasive misconceptions that distort the understanding of trauma in diverse populations. And that has larger ramifications from how health providers approach and care for patients to the kinds of resources that are allocated to entire communities. That’s why I really appreciate Peter’s perspective and humility.

PETER CRONHOLM: For the field to evolve, I think we have to really have an open mind in terms of thinking about what constitutes stressors in people’s lives and recognize that it likely varies dramatically.

PREETI SIMRAN SETHI: And also, as Christine says, outcomes may vary.

CHRISTINE FORKE: It comes across as gloom and doom. This message that we hear, if you have a trauma, you’re going to have all these poor health outcomes. And while that message can be true, it’s not a guarantee.

So we see many people that have a number of ACE exposures, yet they go on to live healthy, happy, long lives.

PREETI SIMRAN SETHI: Which researchers are now trying to understand. They’re investigating the flip side of adversity.

FLORA LICHTMAN: So the flip side of adversity, say more.

PREETI SIMRAN SETHI: The way positive childhood experiences, the love and care we get when we’re young can help mitigate the traumatic experiences that we go through.

FLORA LICHTMAN: You can read all about it at sciencefriday.com/childhood. That’s sciencefriday.com/childhood. Preeti, thank you.

PREETI SIMRAN SETHI: Thank you, Flora.

FLORA LICHTMAN: Preeti Simran Sethi is a science writer and Rosalynn Carter Mental Health Journalism fellow who’s been reporting on Asian mental health.

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