Humans develop. Consider a three year old and how they think: for them, everything is pretty immediate and visceral. You take away the truck or doll and the world falls apart right there and then. Jump ten years and you take away the truck, and the 13 year old is able, more, to wonder what you motivation was, to think about how to socially negotiate the return of the truck, to argue from different perspectives (more). There has been not just a change in the 3 year old to arrive at the 13 year old--there have been whole new capacities to think and relate which were simply not there in the appropriately "Me!" phase. There has been development and there has been transformation (even more clearly seen if you compare an infant with a 20 year old...most of the time).
Change versus transformation
Then compare the difference between change and transformation. Change is when the structure of something--we'll use as an example a political structure--stays intact and the elements move around. Transformation is where the structure itself changes, producing whole different results.
So, lets think of a group of people who are living in a village that's ruled over by a strong-man, warlord type. He is the center of power, and makes all the decisions. A change in such a village might look like a new advisor being chosen for the warlord who changes the man's opinions within a fairly narrow range, but is not able to influence--because the man's a warlord!--him to give away all his wealth and institute a cooperative political structure (for instance). That's change: structure the same, elements different.
Imagine, then, if this same village is exposed, suddenly, to a democratic culture that lands on their shore (or planet if you like Science Fiction). This being a more powerful culture, they start confronting the warlord and influencing the culture through giving resources and challenging old ideas, towards a more democratic structure. At some point, simply appointing different people to the same positions, even the strong man, is not compatible with an emerging democracy, and the culture goes into crisis en route to transforming its political structure. On the other side of that crisis, the village is making decisions by direct vote, there is no strong man, power is shared, and then there is more negotiation (rather than war) with neighbors, etc. In other words, transforming the structure changes the outcomes in a way that's impossible within the more limited (in this case warlord) structure. There has been transformation: the form has been "gone beyond" (the meaning of "trans-").
So, with "transphilia," we need to use this understanding of the difference between change and transformation. And to understand depression as "transphilic," we need to understand that there is a huge gulf between situational depression and chronic depression. And what is that? Situational depression is a triggering of depression from an outside source; chronic depression is the triggering of depression from an inside source. Outside is: death of a loved one, loss of a job, disappointment with a friend. Inside is: the way we think, the way we rigidly refuse to accept reality, the way we feel the world as futile, our conception of our self as broken.
"Outside depression" versus "Inside depression"
The "outside depression" is cured by change strategies, because the cause is not the structure of a person, but the situational influences. You get more support for your sadness around a loss and then move through it. You get support to help you look for a new job and move through it. You look at the unrealistic way you're seeing the situation, correct with better data ("oh, there are this whole set of jobs available to me I didn't know about!") and move through it.
With the "inside depression," the cause is not outside. It's the difference between getting hit with a stick and getting a sore muscle, and having learned to move in a very contracted way and thus experiencing sore muscles. Same soreness (depression), different causes. "Inside depression" is depression caused by the way we move, not by how the world is impacting us, and thus requires a transformative strategy to heal. Why? Because it's the structure of one's self that's actually producing the depression; the "machine" of self is programmed to pump out depression; the stress is not being produced by a lack of oil on the gears. You can "oil" the gears of depression (get more exercise! think more positively!) but if it's truly and "inside depression," then it will fail because the now-more-oiled machine is still producing depression. The only way to solve this problem is to reconstruct the machine. Not for moral reasons ("You're weak!"). Not for ethical reasons ("You're not thinking right!"). But simply for logical reasons: fix the problem where it arises.
Thus, chronic depression is "transphilic" because this "inside depression" arises from the structure of the self (how one habitually does, inclines, and identifies with one's life), and therefore to cure, calls for ("has an affinity for," the meaning of "philic") a transformative approach to the self. The structure of the self has to change so depression is no longer produces; simply changing the elements, as with the village culture, may produce a somewhat better warlord, but simply can't produce "democracy."