When I first got cable, I was ridiculously addicted to the true crime shows for about 2 weeks that was practically all I watched. However, I noticed changes in my breathing and heartbeat as well as nightmares.
Now, although I do still watch the ID channel, I do so in moderation. For example once or twice a week. The other trick is, that as your last show of the evening you watch:
Big Bang Theory
The Little Couple
Honey Boo Boo for example
anything that makes you smile, makes you happy so you can end your t.v. watching evening with your spirits in a good place.