There is so much that we don’t know about what causes mental illness, and very little that we do know. This means that asking why is rather futile at this point, but it’s hard not to. It feels like maybe if I had some idea where my depression was coming from I’d have a better idea how to manage it.
We know that there is 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 is no other known mental illness in the family.
Childhood trauma may be a contributing factor, and there’s some really interesting data from the Adverse Childhood Experiences 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 that that. Sections of genes code for various proteins, but when and how our bodies decide to actually make protein based on that code is studied in 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 is going to be the source of some major discoveries as the science moves forward.
Yet I didn’t have any childhood trauma. Yes, I had the “normal” challenging experiences that people are likely to have, but I was not 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 although I was kind of geeky and unpopular, I was generally quite comfortable in my small circle of close friends. The really challenging stuff that’s happened in my life, including bullying, came after I got sick, not before.
Substance use was never an issue. Yes, I drank a lot of alcohol in my late teens and early 20’s, but there were no apparent negative consequences other than the odd hangover, and 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. 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 around 15 I had a period of 2-3 months with 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 can recall, I was terrified by what I was experiencing, but my mood at the time was numb more than anything. Still, physically there is a definitely a resemblance to what I experience when my depression causes psychomotor retardation (significant slowing of movement and thoughts).
When I had my first episode at 27, it came on over the space of maybe 4 months, triggered by situational stress. 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 something that I had sufficient coping skills that I would’ve expected to be able to handle it. I had two suicide attempts in the space of a couple 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. I stayed well for 4 years, and then got very sick again very quickly, with no apparent trigger. I noticed symptoms coming on and got started back on meds quickly, but within four weeks I ended up in hospital. It took a year and a half, 3 hospitalizations, and many different treatment trials to get into remission. It wasn’t a stable remission, though; there were a lot of bumps that were mostly manageable with increases in my medication dosages. That is, until I had another relapse almost 2 years ago. My illness is now more treatment-resistant than ever.
So where the heck did this come from? I doubt I’ll ever know the answer. In the end I suppose it doesn’t really matter all that much, but 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? There can be no answers, only more questions. I hope that some day science is able to start to answer these questions for others, even if it comes too late for me.