Oh, yeah, Doom 3 was awesome! First 18 I ever played. First FPS, too.
The mental effects were brilliant, too- see, I've always had nightmares. Spiders the size of humans, zombies, nasty aliens, etc. (I blame my mother letting me watch horror films with her when my age was in single figures.)
But the first nightmare I had of monsters after I played Doom 3, I had a gun in the dream. Instead of being hunted, and terrified, I got some other people together, went down into the sewers, and killed the monsters. Amazingly empowering. I woke up overjoyed at our victory, instead of shaking.
Never had a monster nightmare since.