One thing that has become increasingly clear is that the simplistic "too much x" or "too little y" theory of
Mental illness as a "neurotransmitter imbalance" is flawed to the point of uselessness. Neurotransmitters certainly do
mediate synapse growth and activity, but the brain is a complex adaptive organ, and it will adapt to
modifications to neurotransmitter levels. This is why antidepressnts become less effective and require stronger doses, and why their sudden withdrawal leads to the massive exacerbation of symptoms. The problem isn't simply that patients "go off their meds". The problem is that meds stop working, and withdrawing them leaves the poor patient with a brain that was adapted to their presence suddenly unable to cope. The meds make the organic problem worse, but it dorsn't show until you withdraw them. We're still basically at the witch-doctor stage of "try it and see" with most if these drugs, with nothing like a proper pathology model or functional description of how the meds work to even do proper long-term studies.
Full disclosure: there is pretty good evidence that some of these drugs (like SNRIs) are effective for short-term mitigation of symptoms, although not a great deal above active placebo. Some other therapies are very promising, particularly Cognitive Therapy and a guided Mindfulness program (although study quality on the latter is suspect. DO NOT MODIFY YOUR MEDICATION WITHOUT THE ADVICE AND MONITORING OF A MEDICAL PROFESSIONAL FAMILIAR WITH YOUR CASE.
I have often wondered if the adaptive nature of the brain is what's confusing things. In other words, if someone is suffering the systems of major depression or bipolar disorder, and you "shock" that system with a change in brain chemistry, you're going to get change, and that often the change is enough to snap people out of whatever depressive/manic rut they're in. Problem is, that's not a cure.
