TABLE 13.1 DIFFERENTIAL DIAGNOSIS OF AGITATION AND AGGRESSION IN CHILDHOOD Anxiety Adjustment reaction of childhood or adolescence Disruptive behavioral disorders (ADHD, oppositional defiant disorder, conduct disorder) Depression Mania/mixed manic–depressive states Medical illness (including delirium) Pervasive developmental disorders (e.g., autism) Personality disorders Psychosis caused by: Medical illness Ingestion of toxic substance Primary psychotic disorder Other psychiatric disorders (e.g., depression, anxiety, trauma) Trauma It is important to assess patients presenting with psychotic symptoms for their level of premorbid functioning as well as any recent stressors Primary psychotic disorders can present in children who have been previously well adjusted or may have had mild to moderate emotional problems but have been exposed to acute or chronic unmanageable stressor(s) such as trauma or abuse For children who present with a prolonged prodromal period of progressive social and emotional withdrawal, an eventual diagnosis of a chronic disorder such as schizophrenia is more likely