A Selfish Disease?

Yesterday, a trusted friend uttered the words "depression is a selfish illness."
Yesterday, someone who should understand this illness, dared to say that I, and others who suffer depression, are selfish.
Yesterday, because of 5 little words, I felt selfish, which caused me to feel even more depressed.

According to the Oxford Dictionary, selfish is defined as: "(Of a person, action, or motive) lacking consideration for others; concerned chiefly with one’s own personal profit or pleasure."

On the one hand, it is sometimes true that when someone is in a depression, they do lack consideration for others. But this is not always the case. Often we do consider them, but lack the ability to truly help others or be there for them, which in turn causes our depression to worsen. Is this selfishness? Is it selfish to be physically and emotionally incapable of helping other people? 

"Concerned chiefly with one's own personal profit or pleasure"... well, I guess this part could also be considered true - at least to the degree that I do not know a single depressed person who wants to be depressed, and instead does want to find some sort of joy in their life. They do want the personal profit of a full month, or week, or even just a day, of happiness. Is that selfish? Is it wrong to want to not live in emotional pain on a continuous basis? 

For me... when I think of something being selfish, I think of it being a conscious effort to achieve personal gain (or, personal perceived gain). The acts that stem from depression - the inability to put others first, or to do what should be done - are subconscious symptoms of a debilitating disease.  

But, maybe I'm wrong. Maybe even in writing this, I'm being selfish. Maybe that's all it is and all it ever has been.