Another stressor appears to be the separation from his twin brother, Jacob. Nathan and Jacob were very close and he seems to be having trouble adjusting to their separation and making new friends at his new school. Nathan is also afraid and worried about disappointing his family, which seems to be another stressor for him. Additionally, Nathan exhibits emotional disturbance and unusual behavior due to stressors and changes in his life. Nathan presents with a depressed mood in which he has become quieter than usual, more isolated and stays in his room more often, as well as a decreased appetite. Small things seem to irritate him and he speaks to his parents with disrespect and behaves aggressively in a way he never has before. The family explains that Nathan's behavior has never been like this before. It appears that all of these symptoms and behaviors occurred during the transition period to the new school, subsequently causing a change in Nathan's mood and behavior. According to the DSM-5 if these symptoms continue to persist for more than six months, further evaluation will be necessary to determine whether a more serious mental disorder exists.