An exploration of the ways the immune system, epigenetics, affect regulation, and attachment intersect in mental health. The evolution of psychotherapy in the 21st Century demands integration. Instead of choosing from the blizzard of modalities and schools of the past, therapists must move toward finding common denominators among them. Similarly, today’s psychotherapy necessitates the integration of the mind and body, not the past practice of compartmentalization of mental health and physical health.