This is a controversial but very interesting subject to study. I am not going to post any more than this Wikipedia post but there is a lot out there to read. It is politically incorrect because it is negative on adoption (which I’m not). Like I said, very interesting . . .
Adopted child syndrome
Adopted child syndrome is a controversial term that has been used to explain behaviors in adopted children that are claimed to be related to their adoptive status. Specifically, these include problems in bonding, attachment disorders, lying, stealing, defiance of authority, and acts of violence. The term has never achieved acceptance in the professional community. The term is not found in the American Psychiatric Association‘s Diagnostic and Statistical Manual, 4th edition, TR.
History of the term
David Kirschner, who coined the term, says that most adoptees are not disturbed and that the syndrome only applies to “a small clinical subgroup”.
Researchers Brodizinsky, Schechter, and Henig find that in a review of the literature, generally children adopted before the age of six-months fare no differently than children raised with their biological parents. Later problems that develop among children adopted from the child welfare system at an older age are usually associated with the effects of chronic early maltreatment in the caregiving relationship; abuse and neglect.
Psychologist Betty Jean Lifton, herself an adopted person, has written extensively on psychopathology in adopted people, primarily in Lost and Found: The Adoption Experience, and Journey of the Adopted Self: A Quest for Wholeness and briefly discusses Adopted child syndrome.
Judith and Martin Land, Adoption Detective: Memoir of an Adopted Child, (2011), identify genealogical bewilderment, oppositional defiant disorder, selective mutism, anti-social behavior, The Primal Wound, and other related terms to describe potential effects of adoption on children who are orphaned, fostered, or adopted.