A schema can be understood as a system of memories, cognitions, emotions, and bodily sensations. In Schema Therapy, schemas are self-defeating patterns in that they drive behaviour that prevents individuals from overcoming life difficulties and fulfilling their potential.
Dysfunctional schemas are described within Schema Therapy as Early Maladaptive Schemas, because they usually arise in childhood or adolescence.
It is important to remember that, no matter how dysfunctional the schema is, it was originally developed as a strategy for getting needs met.