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The Statistics of Depression

I get emails from depressed people all the time. People looking for answers or help. I don’t have answers, of course, but I try to be open and share my experiences. It’s what I would have wanted, when I was there.

The piece below was written this morning in response to such an email. It’s something that’s been on my mind for a while. There’s no editing, or even proof-reading here. Just wanted to share.


For me, I’m often comforted by statistics, oddly enough.

The big lie of depression is a lie of competence; we think we can understand the nature of the world, or ourselves. But you can’t, and never will. The world is vast, and endless complex, beyond our understanding no matter what we do. Whatever you see, you see as if holding out a picture frame onto a landscape. You see the landscape, but only the section visible through your frame. Your selection is true, sure, but it isn’t the entirety, and never can be.

In reality, nothing is particularly anything – neither particularly good nor particularly bad. Utterly random. Of course, when you are given a truly random selection, patterns emerge. Fill a bag with even numbers of black and white marbles, pick them out at random, and write down your selections – you will run into long stretches of all black, all white, etc. Only when looking at sufficiently large numbers, huge numbers, will the actual ratio of 50/50 emerge.

It is a statistical fact – built into the foundation of the universe – that small sample sizes produce a higher chance of erratic results. From large numbers, truth emerges – from small numbers, we get chaos, the unexpected. This explains all kinds of things in our day to day lives, from how small medical studies often produce miraculous results, only to have those results disappear as the study is duplicated, to how we come to rational, yet completely untrue, beliefs based on our experiences (“all Koreans are jerks,” “People from this state are bad drivers,” etc).

The fact is, the sliver of your life on which you base your immediate emotions and beliefs about the world is a small one. It’s a small sliver of your life, and your life is a small sliver of the world now, and the world now is a small sliver of the history of the world, and the history of the world is the smallest possible sliver of the smallest possible sliver of existence. It is the ultimate in small sample-sizes, given to producing outsized results, either for bad or for good.

This could be dispiriting. After all, it’s random, so it seems that we might be doomed to our small sample size, to it’s propensity for capriciousness. All good, all bad, just the luck of the draw.

But there is another statistical fact, hard-wired into all of existence, that gives me comfort: regression to the mean.

Depression isn’t rational. It’s chemical, it’s emotional, but it is not rational. The hard part is that it often SEEMS rational. It feels real, more real than anything else.

The difference between being depressed and being sad is, I think, that being depressed involves a prediction: this feeling will go on forever. That’s the emotional reality of being depressed – you truly believe that your present will extend forever into your future. You often believe that it also extends into your past, since human beings find it nearly impossible to truly remember past emotional states or beliefs. And so, when you are sad, you are sad right now. When you are depressed, you have always been depressed, and always will be. It’s a crippling, destructive thing – it ruins everything you were, everything you will be. It takes it all from you.

But humans are horrible at prediction, and depressed humans are the worst of all. We tend to predict based on what’s immediately in front of us – if a golfer, for example, has a particularly great game, we predict he will continue to do well the next day. If a business has a poor year, we predict they will continue to do poorly. We are adept at thinking of reasons for these outcomes – he’s the most skilled player, that company is run by an ineffective leader – and so our predictions seem well-founded.

But the world doesn’t work like that. If anything, it’s the opposite – the more outsized the outcome, the more notable the result, the more likely it is that the next result will be closer to the average. This is regression to the mean: all things, given enough time, will trend back towards the center.

Our depressive periods are like freak accidents, like picking all black marbles from the bag for a solid hour. They aren’t the average. They aren’t the mean. No matter how we feel – that depression extends forwards and backwards in time, forever – it isn’t the case.

Emotional states are governed by the same laws as golfers and the economy and marbles in a bag. We trend, no matter how dire things get, towards the mean over time. Things get better, or they get worse, but always we are trending towards the mean. In case after case we’ve seen this – rape victims, holocaust survivors, people enslaved in war zones: an immediate decrease in serotonin and other brain chemicals associated with mood…and, over time, a return to something closer to the baseline. Maybe not average – no one is ever truly average – but something close to it.

So. That’s what I think about. It isn’t advice – there’s no advice that can get you out of depression. Everyone’s different, our lives are different, and in the end, we can’t really know all that much about each other.

But this isn’t advice – it’s math. And the math of the universe says no one is alone, or depressed, forever.