Capgras Syndrome: The Movie!
I kind of like these stories that really don't have any supernatural horror at all. It'd get a little monotonous to have a never-ending stream of "mind of the madman" pieces, but this one was very well done. In particular, I enjoyed the way the protagonist sort of... learned to deal with it, rather than the usual ending of "...and then he killed his whole family," plus lots of gory description.
I think at least one of the people who called my old job every day had something very close to Capgras. It's kind of astounding how many people there are who are trying to live with their delusions and not getting help. Most of 'em don't end up with a stable family life, however inwardly miserable. However, the criminalization of insanity is another rant altogether and not really appropriate here.
I liked this one. I didn't particularly notice the writing, for good or ill, which is probably for the best, and the portrayal of the disorder was pretty accurate rather than sensationalist; someone did their homework, and I can't help but approve of that.
(He should get a cat, though, instead of a dog. Then you don't have to worry about an evil copy trying to kill you in your sleep 'cause the real thing will do well enough.)