Because most of us tend to revert to a teenage or even childhood mentality while in the parental home, living there in your 20s and 30s can undermine your identity as an adult. This can have a knock-on effect on confidence and self-esteem.
If the reason for moving home is potentially embarrassing, such as the loss of a home, job or relationship, the humiliation a person feels is likely to be worse.
There are individual variations. It depends on relationships in the home and also how well various developmental stages were successfully negotiated in the growing-up years. If someone has a strong sense of self as an adult and a good relationship with their parents before cohabiting, they may be fine. For people in their 30s, more life experience and security in their adult identity and relationships could mean it works better. But it could also be more humiliating.
The psychological impact on parents could be positive if they have had “empty-nest syndrome” in the past, as they will love having their children home. But as a result, this might make them over-involved. Some parents may also feel a strain on their relationship because they had expected to be spending more time alone together.
The writer is a psychologist