From The Studies Show* again, which provides good material episode after episode, Does Depression Exist? (Transcript available)
I usually avoid the topic, not because there are no valid questions in the area, but because the valid questions are seldom asked, and one ends up arguing against the same half-truths (or quarter truths) with your own three-quarter truths, so more heat is generated than light. On other sites I might enter into a discussion briefly, but I tend not to put it up here, because once it's happening at my cocktail party I rather have to be involved.
But this episode is good enough that I believe we can invite the vampire over the threshold this time. Yes, there are significant problems in defining and treating many mental illnesses, depression being among the worst. The short version is that the measurements are crude and don't seem to have been improved in years, and the treatments are only partly successful.
One of the reasons that we say that intelligence is a real trait which can be somewhat measured is that when we look at many things which might go into that, we find that they are correlated. We find that the people who compute efficiently also compute quickly, also have high vocabularies, also catch on quickly to new ideas, have better memories, organise things spatially, see connections between ideas, etc. There is still some variation, but there is a clear trend that we are observing a something. This is also true of depression, but much less so. There are usual symptoms we might associate with "being depressed" right off the top of our head, such as sad mood, less enjoyment of activities, poor sleep, poor appetite, less energy. The questions on the tests come at these basic ideas in different ways. One would think that a paper and pencil test might be able to ask things in a repeatable straightforward way, but one of the things we have learned is that depressed people don't think too hard about the answers sometimes. If you have ever taken a test that seems to be asking the same questions with maddening frequency, this is why. You ask if they have been crying more often, and they say no. You ask if they have been getting less enjoyment out of activities they usually like and they say no. You ask if they have been more easily discouraged lately and they say no. Then you ask if they have been feeling more guilty, ruminating on past sins or bad decisions and the light goes on for them. Yes, yes, they have, and suddenly they want to go back to those earlier questions, because come to think of it, they haven't been enjoying things as much. "Now that you mention it, I have had a harder time getting out of bed these last five weeks, even though work isn't really more difficult that usual."
The thing that is often wrong with the tests is that they are only going to give you an approximate measure at best, but people doing research have to treat an average answer of 21 at quite different from an average answer of 23. Over a few thousand people, this is true. But for you, sitting in front of the doctor, it's going to be +/- 4 points that are not that meaningful.
Next up, CBT, SSRI's, SSNI's, energising or atypical antidepressants, coaching, trauma-sensitive therapy - all of these seem to help some. Combos are often better. So why bother if it's only a little? Because with depression, a little improvement is often enough. We are remarkably resilient, and if we have been soldiering on when every morning feels like an oppression, even a minor lift can be huge. One of the toughest things to measure, but generally agreed to be important is the ability to rally temporarily when the chips are down. Even very depressed people can suck it up and say "It's my daughter's wedding. No one is going to see a flicker of depression in me this weekend. I'll collapse Monday."
One can immediately see that issues of character, of training, of duty are huge confounders when measuring depressive symptoms under such circumstances.
But internally, we know that's what we are doing. We feel worse than we did three months ago. We have worse mood, less energy. We call it depression because that's the word we have for it. But all these symptoms exist on a continuum, and they are fairly evenly distributed. The line graphs for infection show a large hump on the left-hand side, a smaller hump far, far up the scale. It's not a continuum. But for depression, there are similar numbers of people at scores of 20, 21, 22...27. We draw lines and say "You have severe depression. You have moderate depression. You don't have depression."
Tangent: I have written often over the last few years about autism/Asperger's/ASD symptoms and these are analogous. If we took an imaginary 1-10 scale for autism, it is not the case that almost everyone is at 1-3 (as would be true with infection) and there is a blip of autistic people at 8-10. It is all more level and gradual than that. Even more, I have come to favor the histogram approach. It's messy. We all have some of it. Some of us clearly have lots of it. We may eventually be able to narrow this down to ten separate axes that interact with each other, but at present, what we have are moderately-associated traits.
So too with depression. We all recognise that there are times we feel worse than others, and unfortunately sometimes much worse. It may or may not be related to an identified cause, such as grief or getting fired, but it's clearly there. At a certain point, we say of ourselves or of others, "this looks like depression." But it's not necessarily one thing.
Of these many symptoms, I was most familiar with dealing with those whose condition was very bad, enough to be suicidal or to stop caring for oneself altogether. I am therefore not a particularly good judge of mild depression. My brother lived with us for six months before I came to and said "Y'know, you're depressed, and I am sorry I didn't put two and two together before." While there are collections of symptoms, it can often be one thing which is bringing on the others. Insomnia is the most notorious of these. Your problem was originally insomnia. But now you have four problems, of irritability, discouragement, poor appetite, anhedonia. We may over the next decades learn to just break it all down into six distinct, interactive symptoms and treat each separately, calling none of them depression.
At the moment I have an unusual situation of being prescribed a chemically-abrasive cream for a week by the dermatologist. It feels like a sunburn, and as if all my life-force is being diverted to fixing my skin. I don't focus well, I am tired and easily discouraged. If by some chance I were taking a common depression test there is a good chance that I would score higher than usual on it, perhaps even high enough to red-flag a professional who saw the numbers that I needed some attention. I would be called depressed. A new observer would wonder whether I was depressed because I look like an albino raccoon. But I don't think that is bothering me much. I accepted that my modeling career was over many decades ago. Yet I feel depressed. Yet I know that i am not really depressed, and will be better in a week when my skin has healed. My energy will not be directed to skin-fixing.
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