Psychology says siblings who become estranged in adulthood were often performing closeness in childhood — held together by proximity and parental expectation rather than genuine connection, and once those external structures disappear the relationship reveals what was always underneath, which is sometimes nothing

Ever notice how some siblings seem inseparable as kids but can barely manage a text message as adults?

I've been thinking about this lately, especially with the holidays approaching. My own relationship with my three siblings has shifted dramatically over the years, and I'm starting to understand why.

The truth is, what we often mistake for closeness in childhood might just be proximity dressed up as connection.

The performance of childhood closeness

When you're kids sharing a bathroom, fighting over the remote, and sitting at the same dinner table every night, you're essentially forced into a relationship. Your parents expect you to get along. Family photos need everyone smiling. Holiday traditions require participation.

But here's what I've realized: that's not necessarily a relationship. That's a performance.

Dr. Laura Markham, a clinical psychologist, puts it perfectly: "Siblings who are close in childhood may drift apart as adults if they don't have a strong foundation of genuine connection."

Think about it. How many of your childhood interactions with siblings were genuine choices versus mandatory participation? The car rides to school, the shared chores, the family vacations where you had no say in the guest list. You were together because you had to be, not because you chose to be.

When the scaffolding comes down

What happens when you graduate, move out, and suddenly those external structures disappear? No more parents orchestrating Sunday dinners. No more shared bedrooms or bathroom schedules. No more automatic inclusion in each other's daily lives.

This is where things get interesting.

Dr. Susan Heitler, another clinical psychologist, observes that "The absence of external structures can expose the lack of genuine connection between estranged siblings."

Without the scaffolding of family life holding things together, the relationship has to stand on its own merits. And sometimes, there's just not enough there.

The surprising statistics of estrangement

You might think sibling estrangement is rare, but the numbers tell a different story. A YouGov poll found that 29% of Americans report being estranged from an immediate family member, including siblings.

That's nearly one in three people.

Even more revealing, research published in the Journal of Social and Personal Relationships found that 17.5% of sibling pairs experienced estrangement, with non-biological siblings who lived together for at least half of their upbringing being more likely to become estranged than full siblings.

These aren't outliers or exceptions. This is a common human experience that we rarely talk about.

The role of family dynamics

Not all childhood homes are created equal. Research indicates that children raised in chaotic, abusive, or neglectful families are at a higher risk of estrangement in adulthood, as these environments significantly impact sibling relationships.

But even in relatively healthy families, the dynamics can be complicated. Parents might unknowingly pit siblings against each other through comparisons. Birth order creates different experiences of the same household. Age gaps mean you're essentially growing up in different versions of your family.

I've noticed this with my own siblings. We each have wildly different memories of our childhood, almost like we grew up in parallel universes that occasionally overlapped.

The weight of unspoken things

Dr. Joshua Coleman, a psychologist, notes that "Unspoken tension is one of the most common reasons siblings become estranged as adults."

Those childhood resentments that never got addressed? The favoritism that everyone saw but no one acknowledged? The different rules for different kids? They don't just disappear when you become adults. They calcify.

In my experience, the things we don't say often speak louder than the things we do. Every family gathering becomes a minefield of avoided topics and careful navigation around old wounds.

When proximity masquerades as intimacy

Here's something I've been reflecting on: knowing someone's daily routine isn't the same as knowing them. You can share a bedroom with someone for eighteen years and never really understand who they are.

Dr. Laura Markham captures this perfectly: "Siblings who were once close may find that their relationship was based more on proximity and parental expectation than on genuine connection."

Proximity creates familiarity, but familiarity isn't intimacy. You might know your sibling's breakfast preferences and their nervous habits, but do you know their fears? Their dreams? The things that keep them up at night as adults?

The possibility of rebuilding

Not all sibling relationships that drift apart are meant to be rebuilt, and that's okay. Sometimes the healthiest thing is to accept the distance. But sometimes, there's potential for something new.

I've found that my relationships with my siblings improved dramatically when I stopped trying to recreate our childhood dynamic. We're different people now. The old scripts don't work anymore.

These days, our Thanksgiving gatherings look different. There are traditional dishes alongside vegan options (yes, they occasionally try my recipes). We've stopped pretending we're closer than we are, which ironically has allowed us to actually get closer. When I stopped preaching about my lifestyle choices and started just living them, conversations became easier.

The key was recognizing that adult sibling relationships are optional. Once I accepted that, I could choose which relationships to invest in, and how.

Wrapping up

The truth about sibling estrangement is that it often reveals what was always there, hidden beneath years of enforced togetherness. Those childhood relationships we remember as close might have been more about sharing a zip code than sharing ourselves.

Understanding this doesn't make estrangement easier, but it does make it less personal. Your siblings aren't rejecting the real you if they never really knew the real you in the first place.

Maybe the question isn't why so many siblings grow apart, but why we expect them to stay together when the only thing they had in common was an address. And maybe, just maybe, accepting this reality is the first step toward building something genuine, whether that's a new kind of relationship or a peaceful acceptance of distance.