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I spent a lot of time in therapy as a kid, for depression, among other things. On and off until I graduated high school, I’d “hang out” in the doctor’s office, playing Connect Four before begrudgingly consenting to more intense discussions. The effect of these sessions was undoubtedly helpful for me. But one thing my self-involved teen brain never considered was that the treatment could improve my parents’ mental health as well.

Preliminary new research, presented at the annual convention of the American Psychological Association on Saturday, suggests that it did: When depressed teens go through some version of mental-health treatment, symptoms of depression in their parents lessen. The finding, based on a study of 325 American teens and their parents, points to what might seem obvious in hindsight: Happier kids make for happier parents. It builds upon earlier research showing how mental health can be relational, hinting that mental-health care benefits not just individuals and their family members, but their entire communities.

Of the study’s participating parents, 87 percent were mothers, following a well-established trend of researching moms’ mental health and the effect on their children. An earlier study of 5,303 women, for instance, found that women with depressive symptoms were significantly more likely to have children with behavioral issues and frequent temper tantrums; another study looked at both adopted and non-adopted children, and found that a mother’s depression affected both her adopted and non-adopted kids. (In that study, fathers only impacted the child’s likelihood of developing ADHD, but another study of families in Ireland and the United Kingdom found evidence of a correlation between depressive symptoms in fathers and their offspring.)

Few studies, however, have looked at how a child might affect their parent’s own mental health. Kelsey Howard, a doctoral candidate at Northwestern University and a co-author of the new research, says she suspects that’s because most of the research done so far has been concerned primarily with the treatment methods themselves, not on the effects of treatment on people’s relationships. “From my own observations, and work I’ve done with families, and, you know, personal experience, it’s clear that kids affect parents,” Howard says.

Her research drew on the data of a large, foundational study from 2007 that looked at how depressed teens responded to two different types of treatments—an antidepressant drug and cognitive-behavioral therapy, a form of therapy that focuses on modifying thought processes and finding solutions—as well as a combination of the two. Sifting through the data, Howard and her colleagues at Northwestern discovered that regardless of the treatment teens received, the psychological health of their parents improved as well. And there was no difference between the type of treatment in the outcome on the parent, Howard says.

While the study wasn’t able to conclude exactly why parents got better as their children got treated, Howard has a few guesses. “It’s possible that the feedback, the control, and involvement in the treatment may have been beneficial,” she says. “It could be in how the family is interacting with each other: The kid is more pleasant to be around, the kid is making less negative statements, which can affect how other family members think.”

“Relationships are reciprocal,” says Laura Mufson, the associate director of the Division of Child & Adolescent Psychiatry at Columbia University, who was not involved in the study. “If one child isn’t doing well, if they’re having mood problems, if they’re more irritable—it’s affecting their behavior that impacts the rest of the people in the family.”

Psychological data increasingly suggests that treating an individual for a mental illness doesn’t simply help them alone. The Centers for Disease Control and Prevention, for instance, has found that depression costs employers in the United States between $17 billion and $44 billion dollars annually, with a loss of approximately 200 million work days a year. (And that’s not counting other mental illnesses such as anxiety, bipolar disorder, or schizophrenia.)

Still, a lot remains to be learned about depression’s broader effects, such as on siblings and peers. Howard—whose new research still needs to be reviewed by other researchers and published—plans to continue to gather data in the field, focusing on adolescent depression and family relationships.

Sharon Hoover, an associate professor of child psychology at the University of Maryland and a co-director of the Center for School Mental Health, studies the implementation of mental-health care in school settings. “Teachers report one of the greatest stressors is mental illness within the student population, so I can’t imagine that if these things aren’t treated, that it won’t affect the overall classroom environment and climate,” she says.

Hoover has high hopes for Howard’s early data, which she envisions could have an impact on the psychological community at large. “This is an incredibly promising finding from my perspective,” she says. “It can be difficult to engage families in children’s mental-health care, but if we see a direct benefit in providing care to children, it shows that children’s mental illness is not isolated.”

Mufson is similarly optimistic. “It’s terrific to have that data,” she says. “I think that it highlights our need to look at the interaction between a teen and their family members … The more support the family can get, the better.”

I know my depression and anxiety impacted my parents, but the extent to which my mental-health care has affected them is hard to quantify. Work like Howard’s suggests that it did indeed make some difference, and that mental health, both good and bad, has a ripple effect—through families, through communities, and maybe even beyond.

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