I Used to Ask ‘Why Me?’ Until I Understood How Depression Happens in the First Place

Introduction

For months I searched for a specific reason. A single event, a particular failure, something tangible enough to point to and say, “That’s why it all happened.” “I never found it, and for a long time I thought it meant I was missing something obvious about myself.”

I looked at the last year almost like a detective, looking for the decision or the moment that started it all. It was certainly a stressful period of work, but not as stressful as I had handled it before. There were some difficult conversations, but nothing intense enough to explain the events that followed. The search itself became a kind of frustration, eclipsing all the feelings I had already felt, and it took me surprisingly long to stop looking for answers that didn’t exist in the way I had hoped.

Over time, I learned that  how depression happens for a clear reason. It’s much more like genetics and life circumstances coming together at the wrong time, neither of which is entirely responsible. How depression happens is actually more complicated than the simple before-and-after story I’ve tried to create myself, and understanding that complexity turned out to be more important than finding an answer.

I am not a doctor or geneticist, and nothing here is a substitute for proper clinical evaluation. But reviewing the original research, rather than finding a clear explanation that didn’t exist, changed the way I understood my own experience.

Why ‘Why Me?’ Doesn’t Have a Simple Answer

Psychologists describe depression through something called the diathesis-stress model: a person carries a certain underlying vulnerability, or diathesis, and depression tends to emerge when that vulnerability meets a significant enough stressor.

I found this model genuinely clarifying once I understood it properly, because it explained something that had been bothering me for a while: why a close friend who’d been through a genuinely harder year than me had come through it without depression, while I hadn’t. It wasn’t a measure of resilience or character. We simply carried different underlying vulnerabilities, meeting different specific stressors, at different points in our lives.

Depression isn’t caused by genetics alone or life events alone. It typically develops when an underlying predisposition meets a stressful enough trigger — which is why two people can go through the same hardship and only one develops depression.

This reframed the entire “why me” question for me. I’d been assuming there was a single root cause hiding somewhere, when the more accurate picture involved at least two separate ingredients working together, neither of which I could have fully controlled or predicted on its own.

The Genetic Piece Nobody Talks About Enough

What Family History Actually Tells You (and Doesn’t)

Depression has a heritable component, with research estimating genetics account for somewhere between 30% and 50% of the overall risk. Importantly, there’s no single “depression gene.” It’s polygenic, meaning many different genetic variants, each with a small individual effect, combine to influence overall risk.

This polygenic detail mattered more to me than I expected. I’d half-imagined some scenario where a genetic test could simply confirm or rule out a predisposition cleanly. The reality is far messier, dozens or potentially hundreds of small genetic variations, each contributing a little, none of them decisive on their own.

Why Genetics Alone Never Explained My Own Case

There’s some history of low mood in my own family, though nothing ever formally diagnosed or discussed openly. Reading about the genetic side gave me a partial answer, but only a partial one. Genetics alone doesn’t determine who develops depression and who doesn’t. It simply shifts the odds, sometimes significantly, sometimes barely at all.

Knowing that family history existed somewhere in the background helped explain why I might have been more vulnerable than someone without that history facing the exact same circumstances. It didn’t explain the timing, though, or why this particular period of my life rather than an earlier one. That gap is exactly where the second half of the picture comes in.

The Life Events That Can Tip the Scale

Stressful Life Events — Loss, Financial Strain, Major Change

A large population-based twin study found that stressful life events meaningfully increase the risk of a major depressive episode, and the relationship appears to be genuinely causal rather than simply correlated. Loss, financial hardship, and major life transitions all featured prominently.

What made this study particularly compelling to me was its design. By comparing twins, researchers could account for shared genetic background and still find that stressful events themselves carried real, independent weight in determining depression risk. It wasn’t simply that anxious or vulnerable people happened to experience more stressful events. The events themselves appeared to causally contribute to the outcome.

Looking back at my own situation through this lens, the period before depression set in had included a cluster of smaller stressors rather than one dramatic event: a difficult work transition, the slow erosion of a friendship I’d valued, and an unusually long stretch without proper holiday or rest. None of these alone would have struck me as significant enough to mention to anyone. Stacked together over several months, they appear to have functioned exactly the way the research describes, as a cumulative stressor against an underlying vulnerability I hadn’t known I was carrying.

Childhood Trauma and Its Long Reach Into Adulthood

One study comparing adults with major depressive disorder to a healthy control group found that 62.5% of those with depression had experienced more than two traumatic childhood events, compared with just 28.4% of the control group. Rates of abuse, neglect, and witnessing domestic violence were all substantially higher among those who went on to develop depression.

The same research found that people who experienced trauma before the age of seven specifically didn’t respond as well to certain antidepressant treatments later in life, which adds another layer to why early experiences matter so much, not just for whether depression develops, but potentially for how it responds to treatment decades later.

This connects closely to how depression can later affect adult relationships, something I’ve covered properly in a separate piece on whether depression can affect relationships, since early relational trauma and adult relationship strain often turn out to be more connected than they first appear.

How Genes and Life Actually Interact

This is the part that finally made sense of my own situation. Genetic and environmental factors don’t operate side by side independently, they interact directly through a process called epigenetics. Difficult life events can effectively switch on genetic vulnerabilities that might otherwise have stayed dormant.

This was, genuinely, the single most useful concept I came across in researching this whole topic. It explained why the exact same predisposition could sit quietly for years, only to become relevant during a specific period of stress. It wasn’t that my genetics had changed. It was that circumstances had activated something that had been present, but inactive, the whole time.

Genetics load the gun; life circumstances pull the trigger. Someone with a genetic predisposition and a relatively stable life may never develop depression, while someone with the same predisposition facing significant stress or trauma may be considerably more vulnerable.

Research on a specific gene variant, the short allele of 5-HTTLPR, found that people carrying it show heightened stress sensitivity and higher rates of depression specifically after a traumatic experience, compared to people without that variant facing the same trauma. It’s a clear, concrete example of genes and environment actively shaping each other’s impact, rather than each working in isolation.

I don’t know my own genetic profile in this kind of detail, and for most people that level of specificity isn’t necessary or even available outside of a research setting. But understanding that this interaction exists at all, that genes and environment aren’t separate columns to add up but actively shape one another, changed how I thought about my own timeline of events leading up to depression. It stopped feeling like a mystery with a missing piece and started feeling like a process that simply needed two specific ingredients to align, which is a far less unsettling way to make sense of it.

Other Risk Factors Worth Knowing

Beyond genetics and major life events, several other factors meaningfully raise risk: chronic illness, substance use, social isolation, and poor sleep all appear repeatedly in the research.

Chronic illness in particular surprised me with how strongly it featured. Conditions like diabetes, heart disease, and chronic pain don’t just create the obvious stress of managing a long-term health issue. They also appear to have direct biological links to depression risk, through pathways involving inflammation and prolonged physical stress on the body.

Sleep deserves particular attention here, since I’ve already written about the two-way relationship between insomnia and depression, and poor sleep functions as both a risk factor for developing depression and a symptom once it’s underway, making it one of the more actionable pieces of this whole picture.

Social isolation is another factor that’s easy to underestimate until you’ve lived through it. Humans are fundamentally social, and prolonged disconnection from meaningful relationships appears to independently raise depression risk, separate from whatever specific life events might also be contributing at the same time.

Once depression does take hold, regardless of which combination of factors triggered it, the actual changes happening in the brain are something I’ve explored in more depth separately, covering the hippocampus, prefrontal cortex, and neurotransmitter systems involved once the condition is established.

What Understanding This Actually Changed for Me

Knowing that depression typically requires a specific, somewhat unlucky combination of genetic predisposition and environmental trigger took away a layer of self-blame I hadn’t realised I was carrying. I wasn’t weaker than people who didn’t develop it. I simply had a different starting point, facing different circumstances.

I’d spent a fair amount of energy comparing myself unfavourably to people who seemed to handle similar pressures without falling into the same place I had. That comparison stopped making sense once I understood that we weren’t actually facing the same risk profile underneath the surface, even if our circumstances looked similar from the outside.

That understanding didn’t replace treatment, and it shouldn’t for anyone else either. Several of the practical habits covered in 5 Steps to Mental Wellbeing remained genuinely useful alongside professional support. But it did change the tone of my own internal narrative, from self-criticism to something closer to simple acceptance of how this particular condition actually works.

What I’d Tell Someone Asking ‘Why Did This Happen to Me?’

There usually isn’t a single, satisfying answer to that question, and I think that’s worth saying plainly rather than pretending otherwise. How depression happens is rarely one clean event. It’s biology and circumstance meeting in a particular way, at a particular time.

If you’re searching for the one thing that caused this, the way I spent months doing, I’d gently suggest that search itself might be part of what’s keeping you stuck. It wasn’t until I stopped looking for a single villain in the story that I could actually focus on treatment and recovery, rather than continuing to investigate a question that didn’t have the kind of answer I was hoping for.

That lack of a tidy answer isn’t a failure of understanding. It’s simply how this condition works, and accepting that genuinely helped me stop searching for a single cause that was never going to fully explain it.

If anything, I’d say the more useful question to ask isn’t “why did this happen to me,” but “what do I actually need right now to get through it.” The first question can occupy you indefinitely without ever resolving. The second one tends to lead somewhere genuinely useful.

Frequently Asked Questions

This article is for informational purposes only and is not a substitute for professional medical or mental health advice. If you are struggling with depression, please reach out to a doctor or mental health professional for support.

Faizan Ahmed

“I am a health content writer who started this journey the same way many readers arrive here — searching for clear, honest answers at the wrong hour, and finding content that was either too complicated or too vague to help. Pure Vitality Tips was built out of that experience. Every article published here is researched first — drawing from peer-reviewed studies, WHO, CDC, NHS, NIH, and leading clinical journals. I am not a doctor, but I take the responsibility of writing about health seriously — because I know first-hand how much accurate information matters.”