What is only child syndrome? by Theresa Lupcho, LPC | Jun 27, 2023 | Children, Teens, & Adolescents, Mental Health Topics, Parenting, Relationships “Only child syndrome” is a popular but controversial term used to describe a set of perceived negative traits or characteristics that are thought to be common among children who grow up without siblings. These traits may include selfishness, loneliness, introversion, difficulty sharing, and an overdeveloped sense of independence. However, it’s…