For a long time I thought fear of abandonment was something other people had. Clingy people. People who text fifteen times. I wasn't clingy. I was the guy who left first, every time, and I didn't see that as a pattern until therapy, a few years ago, made me look at it.
Turns out it's the same fear wearing a different jacket.
So, what causes fear of abandonment in adults? The honest answer is that there's rarely one cause. Most of what's written points at a few roots that overlap: insecure attachment in early relationships, childhood neglect or loss, trauma, and a long string of real rejections. For some people it sits inside a bigger picture, like borderline personality disorder or separation anxiety. Psych Central lays these out well. What they have in common is that the fear was learned. Somewhere along the line, your nervous system decided that people leave, and it's been bracing for it ever since.
Attachment: the first lesson about whether people stay
Attachment theory is the big one. The idea is that the way the people who raised you responded when you needed them becomes a template for every close relationship after. If comfort came and went, you can grow up anxious, always checking whether love is still there. If it mostly didn't come, you can grow up avoidant, deciding you're better off not needing anyone.
Psych Central notes that research links fear of abandonment to insecure attachment, especially the anxious kind. I've read enough about it to see myself in both columns, which is not the fun kind of overachieving.
I'm not going to dig through my own childhood in public. I've never gone looking for one single cause there, and I'm not sure it would help me if I found one. What I know is how the template behaves now, in my mid-fifties.
Loss, neglect and trauma
This part is less theory and more plain arithmetic. If important people left, died, drank, raged, or simply weren't there, a kid learns that closeness can vanish without warning. The NHS page on borderline personality disorder notes that many people with BPD went through trauma or neglect as children, and fear of abandonment is one of the core features of BPD.
It doesn't have to be dramatic either. Emotional neglect, where the basics were covered but nobody really saw you, does its own quiet damage.
Being the odd one out, over and over
This is the root I talk about least in the research and feel most in my own life.
I was diagnosed with Autism Spectrum Disorder (ASD) at 50, in the middle of a breakdown during the COVID years. Before that I had 50 years of being "weird" without knowing why. The tics and habits. The obsessions that made sense to me and to nobody else.
When you're the odd kid, you collect a lot of small rejections. None of them are a big event. Nobody writes them down. A group goes quiet when you walk up. A friend drifts off to people who are easier. You learn to read rooms very closely, because you're always checking how long until they've had enough of you. I think that adds up to its own kind of abandonment training, even if nobody ever technically left. I wrote about the way it plays out in why I leave before I can be left.
I can't prove that link with a study. It's my read on my own life. But I've read enough from other late-diagnosed adults to know I'm not the only one who thinks it.
When it's part of something bigger
Sometimes fear of abandonment is a symptom of a condition that needs proper care.
- Borderline personality disorder. CAMH lists an intense fear of being alone or abandoned among the signs, and agitation with even short separations.
- Separation anxiety. It isn't only a childhood thing. Adults can have it too.
- Depression and trauma-related conditions. Both can make every silence sound like a goodbye.
The first one on that list is mine. I have a BPD diagnosis, along with ADHD and ASD. I dug into how they tangle in BPD, autism or trauma?
What fear of abandonment looks like in grown men
One more thing, because I think it gets missed. The classic picture is someone who clings. A lot of us don't cling. We go cold. We get busy. We get angry. We pick a fight so the leaving has a reason.
Psych Central's list of signs includes pulling away emotionally and using substances to cope. I'll just leave that there. Substance use has been part of my life, and I haven't touched cocaine or heroin in sixteen years. Looking back, I think some of the using was a way to not feel this exact fear. That's a hindsight theory, not a diagnosis.
Does knowing where it comes from help?
Some. Less than I hoped.
Knowing the roots didn't make the fear stop. It still shows up sounding like plain common sense: "they're pulling away, get out first." What changed is that it got less personal. It stopped feeling like proof that I'm unlovable and started feeling like an old alarm that goes off too easily. You can work with an alarm. You can't really work with "I'm unlovable."
The work itself is mostly relational. Therapy that looks at attachment and emotions helps, and so do skills from dialectical behaviour therapy, which CAMH lists among the treatments for BPD. If you're in Québec, the public route starts at 811 or your CLSC, and the Québec.ca mental health page walks through it. If you're starting from scratch, what happens in a first therapy session might take some of the dread out of it.
If this stuff is pulling you somewhere darker than fear, the numbers for your country are on the Get help now page.