turn in upon (oneself)

1. To become more insular and detached from outside people or influences; to cut oneself off from others. He has really turned in upon himself lately. He doesn't want to leave the house or interact with other people at all anymore. I turned in upon myself to deal with my grief, suffering in self-imposed isolation. The island nation turned in upon itself during this period, severing contact with the outside world.

2. To undergo a catastrophic internal failure; to collapse. I left the company just as it had begun to turn in upon itself. It seemed like the whole of society in the war-torn country was turning in upon itself.