An individual displaying condescending behaviour, egocentricity and expressions of superiority is probably suffering from avoidant personality disorder.

Condescending Behaviour

Actions or attitudes demonstrating an implied sense of superiority over others, often manifesting in patronizing or derogatory manners.

Egocentricity

A cognitive trait where individuals have difficulty understanding or considering perspectives other than their own.

Superiority

The condition or belief of being superior, higher in status, or of higher quality than others.