An adjustment disorder is an emotional or behavioral reaction to an identifiable stressful event or change in a person's life that is considered dysfunctional or somehow not an expected healthy response to the event or change. This reaction occurs within three months of the identified stressful event or change happening. The identifiable stressful event or change in the life of a child or teen may be a family move, parental divorce or separation, the loss of a pet, birth of a brother or sister, to name a few.