|I don't have any evidence on this premise, but I believe if you stop watching the news you will be happier.|
The goal of the news is to get viewers for their advertisers. So what will the news show you negative stories? "5 Killed in Horrific Attack," or "NASA just launched a rocket to study comets."
Your local news channel is worse where the topics are murder, crime, rape, robbery, hurricane, tornado...
By the time you're done watching this crap, how do you feel? I'll bet worse than before you watched it.
My basic philosophy is to avoid listening, watching, reading things or talking to people if it makes your angry.
If you partake in social media it's hard not to see this garbage. You can block words and people on Twitter that bring you down.
My key point here is if you can't do anything about it then don't watch it. Matter a fact one of the reasons terrorist commit the acts is to get the free publicity. So by ignoring it, you do put a damper on their ability to terrorize you.