Why does nothing interest me?

I have essentially no interests whatsoever. I don’t listen to music at all. I watch very few movies, and I dislike most of them. Books do not hold my attention; I’ve bought a few, but I never get past page 100. I used to play video games, but even that got boring. Recently I’ve been trying to go back and play some of my old favorites; I get bored after about 10 minutes. I used to be into amateur photography too. On the rare occasion that I convince myself to go out with the camera, I usually give up within 20 minutes or so.

Even the topics that I still count as interests – science, religion, and history – don’t hold my attention. I used to read all sorts of articles, watch videos, and get into big lengthy discussions with people. Now I just stumble past all of those articles/videos, and it’s probably been a year or more since I’ve taken part in any sort of debate.

Is this some sort of psychological condition? What can I do to peak my interest in things again?