"When the term chemical dependent emerged as the new label for both alcoholics and drug addicts, the term codependent was coined to describe their partners (Beattie 1989; Bradshaw 1988; Cermak 1986; Mendenhall 1989; Rothberg 1986; Schaef 1986). Rothberg (1986) articulates the notion that problem drinkers and their partners develop complementary relationships in which each reinforces the pathological needs of the other. Such notions were developed from a crude and simplistic adaptation of systems theory incorporating aspects of the disturbed personality model which Edwards et al. (1973) had discredited more than ten years earlier."
A thoroughly researched view from a government authority. Note: Abuse is abuse, whether physical or mental:
Blaming the Victim: Codependency Model