My Pdoc told me there were 51 different types of depression under the realm of Bipolar Disorder. My friend has a treatment resistant depression. It also has to do with the opioid receptors in her brain not working right.She feels flat 247. Pdoc wants to try her on a new controversial med for this sort of depression-subooxne. She's tried everything,for twenty plus years I say go for it. However finding insurance providers who will cover it is another matter. She just got out of hospital a week ago.