True in spirit, but untrue definitionally. The thing is, the psychiatric profession still basically subscribes to a Behaviorist theory of mind when it comes to treating neurological problems. There's no consideration of what's going on in your head when you have a neurological malady; your head is a black box, where drugs go in, and altered behaviors sometimes come out. "Clinical depression" isn't the name of a specific thing that we know goes on in the brain (in fact, it seems to be a whole cluster of things); rather, clinical depression is "the thing which taking an SSRI usually makes lessen." When a psychiatrist says you may be clinically depressed, what they're really saying is, "you have symptoms that may be manageable by the effects of this or that drug." They have no idea whether they're treating the root cause, or just masking it, and a lot of them don't care. They just want to see your behavior alter, like a rat given a swim test.
And really, thinking of things like SSRIs as "medicine" is part of the problem. SSRIs and the like are crutches--given to you to lessen the symptoms of a problem enough for it to stop being overwhelming, so that you can actually manage to make it to the CBT-practicing therapist every day, have the energy to find the the better job to get away from your horrible boss, etc. I wrote more on this here: https://news.ycombinator.com/item?id=6347620
(P.S.: In this case, though, if I might be a bit more pedantic: I didn't say that all those maladies in my post were caused by those imbalances. I said that inducing those imbalances, in the way that Lyme disease does, will mimic the symptoms of those maladies. Clinical depression may not be "just" a serotonin imbalance--but inducing "just" a serotonin imbalance tends to produce the symptoms of clinical depression. ;)
(P.P.S.: note that I never used the word "disease" or "illness" once. See my link above--these words don't apply to things like nearsightedness, so they don't really apply to the kind of problems neurological imbalances manifest as, either.)