Is There a Root Cause for Depression?

I was recently reading an article that argued that to fully treat depression, one must do the inner work to get to the root cause. That didn’t sit particularly well with me, so I thought I’d write about whether there’s even such a thing as a root cause for depression.

The problem with reductionism

I’m of the perspective that mental illness is complex, and the causes are just as complex. If we get too reductionistic, we can lose sight of what else could be in the picture.

By reductionistic, I mean simplifying the root cause down to being 100% attributable to one thing. That could go in a medical/biological direction, or it could go in a situational/trauma direction. I don’t see either as particularly helpful.

I conceptualize the causes of depression on a continuum from fully biological to fully situational. A few people are at either extreme, but a lot of people are somewhere in the middle. I like the diathesis-stress model, which looks at the interaction between genetic and psychological factors to produce illness.

Genetics

We know that there’s often a genetic element to mental illness, but we know very little about how that actually works. One way of examining this is twin studies. Monozygotic twins come from a single egg and sperm, and so have identical DNA. Dizygotic twins come from 2 separate egg/sperm pairs, so they do not share the same DNA.

The concordance rate (probability of sharing a specific trait) for major depressive disorder in monozygotic twins is almost double that for dizygotic twins. For schizophrenia, the concordance rate is even higher, suggesting an even stronger genetic link.

In my own family, there was one great-uncle (possibly two) on my dad’s side with schizophrenia. That’s it. There’s no other known mental illness in the family.

Childhood trauma

Childhood trauma may be a contributing factor for some people’s depression, and there’s some really interesting data from the adverse childhood experiences (ACEs) research on this. Stress and trauma, particularly in childhood, can cause “epigenetic” changes. We have the genes we’re born with, but it’s more complicated than that. Genes code for various proteins, but when/how our bodies actually make those proteins falls within the field of epigenetics.

Interactions with our environment are a major factor, but there is still so much more to learn in this field. There is even some research suggesting that epigenetic changes can even be passed down to offspring. It’s a really interesting area that I suspect will be a source of some major discoveries as science moves forward.

For me, there was no childhood trauma. Yes, I had the “normal” challenging experiences that people are likely to have, but I wasn’t abused, neglected, or bullied. I was lucky enough to have parents that were caring, affectionate, and supportive. We were financially secure enough that I had opportunities that might not have been available to others. I did well in school, and while I wasn’t popular, I was comfortable in my circle of close friends. The really challenging stuff that’s happened in my life, including bullying, came after I got sick, not before.

Psychosocial factors

Substance use could potentially be an issue for some people, but I don’t think it was for me. Yes, I drank a lot of alcohol in my late teens and early 20’s; however, there were no apparent negative consequences other than the odd hangover. I had no problems stopping drinking when I moved on to the next stage of my life.

I was not someone who was prone to low moods. I’ve always been emotionally sensitive, but overall I was a happy, optimistic person with good self-esteem, a solid core group of good friends, and a career that I found very meaningful. I didn’t have my first episode of depression until age 27, although, looking back, there may have been an earlier hint of things to come.

When I was 15, I experienced 2-3 months of unexplained physical symptoms, including weakness and fatigue severe enough that I could barely get in and out of bed. Various tests were done, but no physical cause was identified. From what I recall, my mood was mostly numb, and I didn’t feel depressed. Still, there’s a definite physical resemblance to depressive psychomotor retardation (slowing of movement and thoughts).

My non-history & the pattern of my illness

When I had my first episode at 27, it came on over the space of maybe 4 months, triggered by situational stress that was not proportionate to how sick I got. My ex-boyfriend and I had remained very close friends after I’d broken up with him, but then he started dating someone and all of a sudden my best friend didn’t want to be in my life anymore. It was difficult, but I had sufficient coping skills that I would’ve expected that I could handle it.

I had two suicide attempts within a couple of months, then ended up in hospital for 2 months, psychotic and continuing to try to take my own life. Later that year, I went off meds because I felt they weren’t working, but I ended up achieving full remission despite that. That was only temporary, and the illness has become far more chronic and treatment-resistant.

From the beginning, my pattern of illness has been most consistent with the melancholic subtype of depression, which appears to have stronger biological roots than other forms of depression. I’ve responded best to biological treatment, particularly ECT.

Where the heck did this come from? Is there a root cause? Why did I get depressed? I doubt I’ll ever know the answer. In the end, I suppose it doesn’t really matter all that much; still, I wish I knew more about this beast that has intruded into my life. How did it sneak up out of nowhere, and why did it pick me? Is it the ghost of that distant great-uncle’s genes swooping in to haunt me but sparing everyone else in the family?

Not everyone is just one way

Whether it’s saying that everyone only needs meds, or everyone needs to do a psychotherapeutic deep dive to get at their deepest inner wounds, saying that depression only exists a certain way excludes and can even alienate people who don’t experience depression in that particular way.

It makes a lot more sense to me to consider everyone with depression as a unique individual who may have multiple factors contributing to their depression. When those factors are identified, they can be addressed in whatever way seems most helpful for the individual.

Trying to fit everyone under the umbrella of a particular “root cause” for depression will inevitably leave some people out. Throwing meds at someone whose depression is heavily influenced by unaddressed trauma is likely to be just as ineffective as having someone whose illness is quite biologically rooted go to psychoanalytic therapy to explore their Oedipus complex.

For now, science hasn’t given us a lot of answers about whether a root cause for depression exists; only more questions. Maybe we’ll get there, but for now, let’s throw away the boxes, and recognize people for the complex individuals that they are.