The voodoo of loneliness is well-known. From caveman times those who didn't know how to form relationships and become part of the group tended to perish. Survival depends on how well man the social animal performs in relationships.
With citations of research and quotes by experts, Elizabeth Bernstein confirms that in an article in THE WALL STREET JOURNAL. Here you can read it.
In the eight years I have been interacting (an overstatement about the quality of the encounter) with lawyers, I have found those who are in professional hell also tend to be lonely. Somewhere along the line they found the way to deal with challenges, including emotional ones like insecurity, is by turning inward. Often they do that so successfully that they can't find the way out of themselves. Consequently they are blocked from all the opportunities which come our way through people.
In addition, a number have confided suicidal ideation. THE WALL STREET JOURNAL sums up lonely people as those who shorten their own lives. Not being able to connect is as much a health hazard as alcoholism and being around toxic materials.
The first step back into society is to stop judging. Things are as they are. Sure there are a handful of successful change agents around such as Nelson Mandela. For the rest of us we have to suck it up and then when we create other opportunities for ourselves find a better fit of an environment.
The next step is listening. Giving another human being our full attention is the ultimate power gesture. If we don't take a peek at our smartphones when they are talking, they are apt to become a loyal friend for life. They may happen to be a partner who can be useful in our career trajectory. We don't need many friends. Just a few. One means that you have achieved plenty.