The family as a biologic and biobehavioral unit provides a scientific, humane, and useful approach to the theoretical, diagnostic, preventive, and treatment components of child and adolescent psychiatry. Principles of evolutionary biology, including inclusive fitness and kin selection theory, as well as aspects of experiential family psychotherapy, are discussed in the context of recent studies on the biology of experience, learning, memory and the representation of interval working models. The major theoretical underpinnings of the traditional family psychotherapeutic approaches are consistent with both the principles of evolutionary biology and recent advances in our understanding of the mechanisms by which experience is translated into biologic processes. Evolutionary biology provides a framework within which must scientific aspects of child and adolescent psychiatry can logically be synthesized. Clinical work with families can he augmented by incorporating a comprehensive biologic framework into theory, diagnosis, prevention, and treatment.
