Codependency grew out of the term ‘co-addict.’ The codependent person, or the co-addict, was that person who got sick through living with the distorted, unregulated, and out-of-balance thinking, feeling, and behavior that surround addiction.
Dayton traces codependence’s etymology from ‘co-addict’ and situates it historically as a developmental disorder with neuropsychological roots in relationship trauma.
, Emotional Sobriety: From Relationship Trauma to Resilience and Lasting Fulfillment, 2007thesis