I saw this article on my Facebook feed a few days ago, and it’s been popping up in various social media fora since then. Everybody seems excited about it, and I don’t get that reaction. Personally, it worries me.
I’ve been wary of the biological explanation for mental illness for a long time. No matter how many times people insist that it’s an illness just like diabetes, that doesn’t make it true. There is some overlap, sure–it tends to be chronic, it’s invisible, and lifestyle changes can help many people manage the symptoms. But depression, unlike diabetes, is not a purely physical disease.
This study, despite what a lot of people on Facebook think, does not prove the biological/neurochemical hypothesis of depression, nor does it provide a test to “prove” whether someone has depression or not in the way someone tests clearly positive or negative for, say, strep throat or diabetes. In my understanding, this study says much more about the epigenetics of depression than it does about the neurochemical hypothesis. (For purposes of disclosure, I only scanned the actual study, and I’m not a doctor or a scientist.) Also, it’s a very small study, only 32 people. That’s far too small to draw any major conclusions.
My worry is that people will take a study like this and use it the wrong way. A lot of the sentiment I saw on Facebook was along the lines of, “At last, we can finally prove that most of these whiners are just faking depression for sympathy!” Depression is a complex disease with many causes and extenuating factors, so I doubt that everyone’s experience of depression can be attributed to nine RNA markers. What will happen to people who experience symptoms of depression but test negative? Will they be accused of malingering or attention-seeking? Will they be denied treatment because their depression isn’t real? It’s already too hard to access treatment, and I can see this test being used to deny access to certain people.
My other worry is similar but more specific. This study shows that certain people will benefit from therapy (specifically CBT, in this case) while other people won’t benefit. Again, it all comes down to those nine RNA markers, which can’t account for someone’s motivation or willingness or desire to get better. If someone’s labs show that they won’t benefit from therapy, will insurers be allowed to deny them access to it? Will an RNA marker that says someone won’t benefit from CBT also be used to deny them, say, DBT or psychodynamic therapy? After all, the insurers will say, why should they be forced to pay for treatment for people who won’t get better anyway? We now have mental health parity laws (unless you’re on Medicare, in which case you’re only allowed to be crazy for six months in your entire life), but I can easily imagine a new system where mental health care must legally be covered just like physical health care, but only for people whose genes say they’ll benefit. The rest will just be left to fend for themselves.