So what's the difference between depression and a philosophical despondency?
If there's a distinction, it's between something that is a neurological/chemical disorder and a philosophical outlook. The first is a mechanism and the second is a symptom, with the second having more than the first as a possible cause. The former can create the latter, and the latter can engineer a remarkable simulation of the former and recreate its effects, but they're easily conflated for those reasons.
The first one amounts to someone with a vitamin deficiency of the brain. The second is Zetsubo-sensei.
The best description of depression I've heard was from an acquaintance who'd received both therapy and drugs. The way he put it was, "I felt like I was being held hostage by my own mind." It didn't matter what he thought about; it was all subsumed into the service of the depression. His despondencies occasionally could be made concrete in the form of a complaint about something (e.g., what's this country coming to!), but for the most part what he experienced was just a blanketing, smothering pillow of negative emotion pressed down over the face of his brain.
So he got help, and that help came in the form of both drugs and cognitive therapy. The drugs cleared the fog; the therapy that allowed him to avoid recreating the same states of mind that he had become overly familiar with as a response to certain situations. He's doing damn good now. (I'm not going to attempt to defend all psychiatric drugs, only to say that they have their place and that the choice is not an all-or-nothing split between pills and Plato.)
What bugged my friend a great deal were the well-meaning people who tried to help but had no idea how to offer useful advice. The ones who disdained the use of psychiatric medicines, who told him what amounted to a nicer version of "it's all in your head" and "toughen up and deal". The people who deliver such nostrums, I think, do so because they sincerely believe everyone else has the same easy access to forging such strategies of life from the inside — that it's mainly a matter of willpower.
It's not. Willpower's the fuel for the engine, but if the engine's missing spark plugs you're wasting your time. You can't think your way out of something you didn't think your way into to begin with. Or, as Robert Cray once said, you can't fake what you don't have. Telling someone they can get out of this box by just stiffening their spine and smiling in the mirror every morning is cruel and misleading.
Note that I'm not talking about the kinds of behavioral modifications that are taught in therapy, which are a lot more focused and don't consist of existential affirmations of purpose but rather on-the-spot problem solving techniques. I wonder sometimes if the "suck it up" crowd have internalized those same techniques and just don't know that they're employing them, or don't know how to describe to others that's what they're using.
Evidently "Know Thyself" is not a demand you can fulfill once and be done with it.
It's a shame the author of the piece had to go and invoke Kierkegaard, one of the most pompous and obtuse philosophers on record who badly muddies what little case he has to make with his language-juggling. Reading him is like plugging through deep mud while wearing wooden sabots. I guess he was invoked for the sake of his heft as an Authority, a sort of life-of-the-mind Great Books antidote to those nasty pills. Doesn't make him any less obscurantist.
As Bertrand Russell proved, most people will pay through the nose for obscurity when the plain truth can be had dirt cheap. It's just that the dirt-cheap plain truth is usually butt-ugly to boot.