[michaelochurch]

not all cases of depression can be attributed to unbalanced brain chemistry. sometimes the chemistry is ok, it's just your life is fucked. in this case depression is a normal reaction.

PTSD is also a normal reaction (to extreme circumstances) but it's maladaptive.

Still, I disagree with you that actual depression is a "normal reaction". Sadness and anger are normal emotions that normal people feel. Depression is something else.

People tend to conflated depressed mood, which is transient intense sadness, with the disease of depression, which is something else-- much longer lasting and more devastating.