These results confirm my anecdotal experience. I moved across the country recently, leaving behind all meaningful relationships except for my SO who I moved with. My mental health quickly took a nosedive. I don't connect with anyone at my new job on a deep level, and despite my efforts so far I have no close friends outside of work either.

At least now I know there's a study to confirm why I've been so depressed lately. That counts for something I guess.