By Erin Runt, LMFT
This is the first blog post in a series of posts I’ll call: The Sibling Therapy Series: Seeing the relationships we've learned to overlook. This will be a series of ten or so posts about sibling therapy, directed at either the people seeking sibling therapy and sibling relationship knowledge for themselves, or, the people providing these services who want to know more.
If you’re reading this, there’s a good chance something is off with a sibling. Maybe you’ve drifted and you’re not sure how it happened. Maybe you have the same argument every time you’re in the same room. Maybe you’ve been estranged for years and you don’t quite know what to do with that. Or maybe things are fine on the surface, but something has always felt unfinished between you, and you’ve never had a space to say so out loud.
You’ve probably heard of couples therapy. Maybe you’ve been. You might know that family therapy exists. But sibling therapy? Most people haven’t. It wasn’t in your therapist’s graduate training, it’s not something most clinicians market, and it’s rarely mentioned in the mental health conversations happening online. Which is strange, when you think about it, because no one else has likely watched you across as many versions of yourself as a sibling.
Here I explain more about what sibling therapy is, and how to know if it might be worth considering.
The relationship that gets skipped
When couples struggle, there’s a clear path: couples therapy. When parents and children are stuck, family therapy exists for that. But siblings? The assumption seems to be that adult sibling relationships are just what they are. That the patterns that formed in childhood are fixed. That estrangement is just distance. That conflict is just personality.
None of that is true.
The sibling relationship is one of the most formative relationships of a person’s life, and one of the most consistently neglected in therapy. It’s treated as context, as background, as something to mention in individual sessions but not to address directly. Sibling therapy changes that. It treats the sibling relationship as the subject of the work, the thing that’s worth showing up for, that’s worth naming, that’s worth actually trying to change.
Why sibling relationships are so hard, in a specific way
You didn’t choose your sibling. You didn’t choose the family you grew up in. You didn’t choose the role that got assigned to you, or the way your parents navigated the space between their children, or the ways the family system shaped who each of you became. You were assigned to this relationship before you could speak, inside a system you couldn’t leave and couldn’t negotiate.
That matters. Unlike a friendship, which you can walk away from when it costs too much, or a romantic relationship, which you enter as an autonomous adult with the power to leave, the sibling relationship was not chosen. Its earliest patterns were installed in childhood, in conditions of genuine powerlessness. And those patterns have decades of practice behind them.
Here are a few of the things that make sibling relationships distinct:
You were peers inside a hierarchy, without any power. The parent-child relationship is always hierarchical, and even in adulthood, the emotional weight of that dynamic doesn’t fully resolve. The sibling relationship is structurally different: it begins as a peer relationship, lateral rather than hierarchical. But unlike partners who chose each other freely, siblings were peers inside a system neither of them controlled. That combination, peer status without autonomy, creates dynamics that aren’t quite like anything else.
Shared adversity doesn’t produce shared experience. Two siblings who grew up in the same family moved through that family in different bodies, at different developmental stages, in different positions in the family system. What your older sibling experienced as “fine” may have been genuinely hard for you. What felt like favoritism to you may not have registered as a pattern to them. You can grow up in the same house and have almost no overlap in your experience of it. When those versions of the family come into contact in adulthood, it can feel like you’re talking about two completely different childhoods, because you kind of are.
Roles get assigned and rarely get updated. In most families, children are sorted into roles, the responsible one, the difficult one, the funny one, the golden child, the scapegoat, often without anyone deciding on it. Those roles were shaped by birth order, gender, temperament, what the family needed, and what was happening at a particular moment. Every role, including the “good” ones, carries a cost. The responsible one may have had their competence recognized, but at the expense of being allowed to need anything. The funny one may have been loved for their humor, but not always taken seriously.
What therapist and sibling therapy pioneer Dr. Karen Gail Lewis calls “frozen images,” the tendency to keep seeing a sibling as they were at twelve, or at seventeen, regardless of how much either person has grown, is one of the most persistent features of adult sibling conflict. You may have done real work on yourself. Your sibling may have changed significantly. But if you’re still relating to each other through a lens formed in childhood, none of that growth has anywhere to land.
In some families, older siblings became attachment figures. In families where parental availability was limited, because of illness, addiction, economic stress, immigration, depression, or absence, older siblings sometimes stepped into a caregiving role that goes beyond ordinary sibling influence. If this was your family, you may be navigating a dynamic in adulthood that functions less like a peer relationship and more like a parent-child bond, with all the complexity that implies: dependency, resentment, grief, love, and a particular vulnerability to rupture.
What sibling therapy actually is
Sibling therapy is relational therapy with the sibling pair (or group) as the clinical unit. Most of the work happens in joint sessions, both siblings present, a trained third party facilitating.
The therapist’s job is to work with the dynamic between you, not to evaluate who is right. Their alliance is with the sibling relationship as a system. That means both siblings get the same quality of attention, the same curiosity, the same care. It also means the therapist is tracking the pattern between you, not building a case for either side.
What the work looks like, roughly:
Early sessions focus on establishing safety and getting a working picture of the dynamic. What’s the pattern between these two people? Where does one pursue and the other withdraw? What is each sibling afraid of? What are they reaching for beneath the conflict? Identifying the cycle, the shape of how things go wrong between them, is usually where the work starts.
Middle sessions involve the harder, slower work: helping each sibling update their image of the other, examining shared family history from multiple vantage points, loosening the role assignments that no longer fit, and building new ways of relating that aren’t just re-runs of the childhood dynamic.
Later sessions address what each sibling actually wants the adult relationship to look like, by conscious choice, not default. Sometimes that’s repair and greater closeness. Sometimes it’s a workable equilibrium that’s less than what either hoped for. Sometimes it’s clarity about why a relationship has to stay limited. All of those can be valid outcomes.
Individual sessions alongside the joint work are sometimes appropriate, to prepare for a difficult conversation, to give a quieter sibling space to find their voice, or to process something before bringing it into the room together.
Who sibling therapy is for
You don’t have to be in crisis to benefit from sibling therapy. People come for all kinds of reasons:
Some come because a specific event has brought things to a head, a parent’s illness, a death, an inheritance dispute, a falling-out that crossed a line. These are the most common triggers, and they’re valid ones. When an external stressor lands on an already-strained sibling relationship, it can feel like the relationship itself is the emergency, because it kind of is.
Some come because they’re estranged, or close to it, and they want to understand what happened, even if reconciliation isn’t a goal. Estrangement is not a failure. Sometimes it’s the healthiest available choice in a hard situation. But understanding why it happened, and being honest about whether it’s really what both people want, is almost always worth something.
Some come because there’s a pattern that’s been running for years, the same argument in different forms, year after year, and they’re tired of it. They’re not in crisis. They just want something to be different.
And some come proactively, because they value the relationship and want to work on it before a crisis forces them to.
A word on what sibling therapy isn’t
Sibling therapy is not mediation. It’s not a space where the therapist hears both sides and issues a ruling. It’s not about deciding who was right about what happened in 1997. It’s not going to give you a sibling who is different from who they are, or undo what was hard about your family of origin.
What it can do is help you and your sibling see the pattern between you, not just the current argument, and understand where that pattern came from. It can give language to experiences that were formed before you had words for them. It can create enough safety that both of you can be honest in a way that hasn’t been possible. And for many people, it’s the first time their experience of this relationship has been treated as something worth taking seriously.
That, by itself, is not nothing.
About Erin
I’m Erin Runt, a licensed marriage and family therapist practicing virtually in Illinois, Oregon, Washington, and Arizona (and registered for telehealth in Idaho and South Carolina). Sibling therapy is one of the specialties I’m most drawn to and most frequently asked about. My work has been featured in The Atlantic and SELF Magazine specifically on the topic of sibling relationships and sibling therapy. The clinical frameworks I draw on include Emotionally Focused Family Therapy (EFFT) and the foundational sibling therapy framework of Karen Gail Lewis, EdD, whose work I’m glad to credit every time I reference it. The concept of “frozen images” and related frameworks referenced in this post are drawn from her clinical work. See drkarengaillewis.com.
If any of this resonates, I’d be glad to talk. You can reach me through erinrunttherapy.com.