What is the root cause of perfectionism?

The root of perfectionism is believing your self-worth is based onyour achievements. Perfectionism is often present when somecombination of these factors exist: Rigid, high parental expectations. Highly critical, shaming, or abusive parents.

Is perfectionism a mental illness?

While not considered a mental illness itself, it is a common factor in many mental disorders, particularly those based on compulsive thoughts and behaviors, like obsessive-compulsive disorder (OCD) and obsessive-compulsive personality disorder (OCPD).