And, to add to the witches brew, we have the Quarter Life Crisis Scenario as well:
We all go through life transitions, from adolescence, to 20's and 30's, and so forth. If a person is able to navigate the life transitions properly, they will not suffer from a crisis, i.e., it's just a blip on the radar for those who are successful.
Those individuals in their early 20's and 30's that have difficulty navigating their lifes' transitions will have a crisis and act out. It's all about growing up and leaving childhood/adolescence behind and facing the world of adulthood, accountability and responsibility. They often have feelings of being lost, scared, lonely, panic or confusion about what steps to take in order to properly become adults. Unemployment and choosing a career path is a major cause for young adults to undergo stress and/or anxiety. Early stages of one living on their own for the first time and learning how to cope w/o parental help can also induce feelings of isolation and loneliness. Marrying and becoming a first time parent can also create anxiety as well. These are just a few examples.
As I mentioned, if they do not navigate the life transitions properly or stop in the middle of the QLCs, they will have a crisis at a later time and usually it is a full blown crisis, i.e., the MLC.
This is just my opinion on the subject.
Also, I noticed from your original posting over on Newcomers that you mentioned he had talked about running away. Maybe a thread that I created a long time ago might shed some light on what he's feeling: