I have absolutely no idea what the article says and i am in no way trying to pass off what im about to say as fact but i imagine its not actually the loneliness that's unhealthy but what you do when you're in that state such as not eating or eating to much, laying around all day feeling too unmotivated to even get out of bed, drinking alone to feel better or at the very least not at all, loneliness ties in well with depression so suicide is another issue