Regression in adults can arise at any age; it entails retreating to an earlier developmental stage (emotionally, socially, or behaviorally).
My daughter who is 24 has regressed over the last 3 years. She got a place at Westminster University and had a self-contained flat. However, this arrangment.
Regression psychology entails an adult dealing with a problem like an adult, as opposed to regression to childhood. Get a full read about it in this post.