​A child psychiatric expert witness is a mental health professional who assesses and provides expert testimony on the mental health of children and adolescents in legal cases. They evaluate emotional, behavioural, and developmental issues, offering opinions on matters such as competency, trauma, and custody. Their assessments involve interviews, psychological testing, and reviewing relevant history. Based on these findings, the expert prepares reports and may testify in court to explain how mental health factors influence legal decisions, particularly in family law, custody disputes, and cases involving abuse or treatment concerns.