Pediatricians can provide a wide variety of care to children and adolescents with complex disorders, depending on their training as well as interests, but they need to work closely with professionals in psychiatry and psychology when dealing with complex issues in mental health disorders. Behavioral health screening is therefore an important task of pediatricians and behavioral pediatricians as they evaluate their pediatric patients. Section one looks at what is called special issues in mental health that include suicide/self-harm in pediatrics, childhood-onset schizophrenia, child abuse/maltreatment, mental health issues of chronic disorders (i.e., diseases of the cardiovascular system, the kidneys and the liver), and behavioral/emotional effects of COVID-19 on children/adolescents. Section two covers various aspects of substance use disorders (SUD) that include SUD neurobiology, substance use/abuse in adolescents, an overview on cannabis, psychosocial treatments of SUDs, pharmacologic management of SUDs, and pharmacology of tobacco abuse. Section three provides a critical look at mental health management that includes psychotherapeutic interventions (i.e., children, adolescents and families), behavioral/cognitive behavioral therapies and principles of psychopharmacologic management in pediatric persons.