As someone who has taken a variety of treatments for depression (never SSRIs -- only Bupropion, St. John's Wort, and most recently S-Adenosyl methionine, or "SAM-e") I can say from my own personal experience that they most definitely do _something_, and for me it's almost always positive. In fact, the only reason I've begun to suspect the role of "chemical imbalances" (which are likely caused by the environment and my own response to it) is because of SAM-e's effectiveness.
I have absolutely no financial interest in saying so, but because of its positive effects I'd like to make a plug: SAM-e has been completely wonderful for me -- it's worth checking out the extensive literature on it, which show results that are arguably more impressive than those of the SSRI and tricyclic crowd, especially because SAM-e has virtually no negative side-effects.
The problem is that virtually every form of sensory or neurochemical novelty elevates mood: acupuncture, aromatherapy, sex, exercise, socializing, sensory deprivation, electrical stimulation, god helmet, music, binaural beats, self-mutilation, menthol, etc.
Similarly, every conceivable way you can possibly monkey around with your brain also raises your mood: raising dopamine, lowering dopamine, raising serotonin, lowering serotonin, raising norepinephrine, lowering norepinephrine, etc. You'd literally be hard pressed to find any form of novel sensory stimulation that didn't improve mood, at least in the short term. So why the focus on serotonin depletion? There's no real evidence for it, it was just an arbitrary decision made by drug companies based on the very early research in the field.
I don't think anyone would argue that messing around with a person's serotonin levels can't elevate their mood, at least for a while. The issue is that there isn't any real evidence that the depression springs from a chemical imbalance, and there is definitive proof that longterm messing with your neurotransmitter levels causes semi-permanent changes to the structure of the brain which we don't really understand.
Also, for what it's worth, St. John's Wort is believed to be an SSRI, at least according to Wikipedia.
The issue is that there isn't any real evidence that the depression springs from a chemical imbalance
Well, if its not a chemical imbalance, what is it? Neurotransmitters do the work of transporting signals through the brain - they tell neurons when to fire and what intensity to fire with. If its not a neurotransmitter issue, then what is it?
If the brain only had a couple of neurons, then it might make sense to pump up the transmitters between them to get a more intense response because you don't need very refined control. However there are 100 billion neurons in the brain, and are connected in very complicated ways.
Since there's evidence that cranking up the seratonin for _every_ neuron or suppressing the dopamine for _every_ neuron isn't healthy, it stands to reason that treating "mental illness" is more complicated than turning a water faucet on or off. Who knows exactly what causes it? It could be related to patterns of connection, i.e. neuron A is better off connected to neuron B at site C, but is connected strongly to neuron D at site E. And then comes the question of whether the neuron is sending weird patterns of action potentials. Or it could be the timing, speed or synchronization compared to other neurons is off. Or it could be poor overall health of each individual neuron. Or subtle brain damage. And the problem might be localized to just some neurons in one part of the brain, and not another, making treatment of the whole brain with drugs a messy approach. You see, there are no obvious answers right now, but there are plenty of alternate explanations besides global chemical imbalance. :)
EDIT: Also, you could think of mental illness as being psychological, and something that the brain can heal on its own, given the right environment.
I think a good analogy is when you leave a paused DVD on a plasma TV for too long so it starts ghosting. Your brain, being a neural net, works suspiciously like a neural net. If you 'practice' being depressed for long enough then it's going to get easier and easier to be depressed, and being not depressed gets harder and harder.
That's not to say what actually causes mental illness or what the solution is, but if you want a metaphor that operates on the hardware layer of abstraction that you can frame other theories and/or best practices in terms of then I think that's probably as good as any.
I had virtually the opposite experience to you, including it for the sake of discussion. I'd tried most of the same list as you and had very little positive outcome (all over the counter items or meds that were easy enough to get by saying the right things in order to a local GP)
Through the period I'd experienced some significant lows that all met different criteria - extended depression, severe self harm and mutilation, social difficulties, drugs, alcohols, other unsavoury behaviour (not quite hookers and blow but close enough). Most of the chemical strategies weren't effective, or it was easy enough to discontinue them them shop around for something else a few weeks later.
In the end, I think I reached a point where I was genuine about change and engaged with a psychologist, and within a couple of months the outcomes were very apparent, and positive. Not saying its a good measure of anything either way, just a demonstration of another scenario I suppose.
I'd agree with you on the psychotherapy thing. I'm currently in some pretty intense therapy and it's been really good. I would recommend it strongly to anyone who can afford someone they're willing to trust.
I can't tell from your response, though, if you had tried out SAM-e ? I called it a drug earlier, but it's currently sold as a (n admittedly pretty expensive) supplement. It's hard to find a research study that doesn't show a pronounced effect of the supplement over placebo -- in fact, it was my psychiatrist who recommended it to me (I had stopped taking the bupropion and things were getting pretty bad again).
I should add that the reason I stopped taking the bupropion was that I felt it "worked" by turning down the gain on the more critical parts of my mind, rather than allowing me to reinterpret my own critical thoughts. In other words, I felt like it improved my mood but made me a bit more dimwitted.
I managed to resolve my depression/anxiety with magnesium, 5-HTP and Rhodiola Rosea. I've also had huge realisations about how simple most mental health problems are, when approached from the perspective of removing the cause as opposed to treating the symptoms.
The pharma industry is likely lobbying against these simple treatments because they are not patentable. No single company stands to profit from them. Capitalism provides a rather ugly way of dealing with this issue (and yet people still insist that it's the best system we have). I really do think that the lack of real solutions in the mainstream are a result of economical and political idiocy.
I was/am scared of the long term effects of psychoactive medication, and so wanted the least potent thing available. Plus SSRIs have side-effects that made me less-than enthusiastic.
I've known two people who've been on this stuff. It's pure evil - nearly killed both of them through side effects and made the problem significantly worse:
I have absolutely no financial interest in saying so, but because of its positive effects I'd like to make a plug: SAM-e has been completely wonderful for me -- it's worth checking out the extensive literature on it, which show results that are arguably more impressive than those of the SSRI and tricyclic crowd, especially because SAM-e has virtually no negative side-effects.