How do you mean unsubstantiated? If you mean it's less than certain than sure, but SSRIs and SNRIs and NaSSAs and such improve depression greatly for many patients. That at least says something about serotonin levels in patients with depression.
Depression is different for different people. It's an umbrella term that captures many different types of illness.
Anti depressants do work very well for some people; not so well for others; and not at all for others. Some people may have to try different meds. We know there's a genetic factor with effectiveness too.
But it's useful to have other approaches to treatment, and that's where the good psychologists come in.
There is always a bit of a kerfuffle between psychologists ("It's all psycho-social!") and psychiatrists ("It's all chemistry!") (the analogies with computer language flame wars are obvious) and the truth probably lies somewhere in between.
Indeed. It blows my mind sometimes how much people, including people who really ought to know better, grasp at the ideal of having the One True Explanation and One True Treatment for depression. It's not even just the division between biological and psychosocial approaches; I've seen some very troubling, almost childish bickering among adherents of various psychotherapeutic schools (some of the more esoteric and old-school types denounce CBT in much the same terms that they denounce drugs), and have learned the hard way that if I ever hear my psychiatrist tell me that something is "a really good drug", I need a new psychiatrist.
And by studying how they work we learn about how pain works. Compare to alternative, "keep smiling and find better friends". Fuck that. Even if it was relevant (it probably isn't), I can't smile or talk to people, because I'm constantly in agony because of my arm. I'll stick to opiates because they let me live.
The point in the analogy though is, the pain is a symptom. Understanding how pain is transmitted through nerves and how to block it is certainly useful in the treatment of broken bones, but far more important is understanding that the pain is caused by the broken bone. The pain itself is not the problem, even if makes sense to ameliorate; focusing on the pain instead of the break can lead you to masking and failing to treat the underlying problem, allowing it to worsen.
Yeah, I get the point of the analogy, but I think in reality, the "social" approaches to solving depression are closer to curing broken bones by telling patients to change friends / sleep more / find God. And I say this as a person who had depression and anxiety issues for a long time. Yes, some parts of it are affected by my life conditions, but sadly I can't wish my way out of sudden, random anxiety attacks.
