Addiction is a serious and fascinating topic and one which has in recent years sort of come out of the closet as a hidden facet of human existence.
With the recognition of alcoholism as an actual disease that can be passed down both culturally and genetically from one generation to the next, more and more outstanding work has been done to shed light on the numerous causal factors and impact of addiction on people, families, and communities. The sense of shame and hopelessness that people often feel is sometimes a stumbling block as they recognize their problems, but then go through denial and lose sight of how to begin the recovery process. A fascinating article about this can be found here: http://www.bma-wellness.com/papers/Obstacles_Recovery.html.
But in the scheme of things, addiction to drugs and alcohol, and now, even food and work are being recognized as common sources of addiction for many, we are left to wonder, can people be addicted to other people?
When I was a younger person, the term "co-dependence" was tossed about mightily. It denoted the state of two or more people, whether they were lovers, spouses, family members or even friends or co-workers, who formed unhealthily close attachments to one another wherein the personal growth of one or the other or both was stifled. It is often the result of one person being a true "addict" whether to alcohol, drugs, sexual behavior, gambling or work, and the other falling into a sort of "personal assistant gone haywire" mode for them.
Co-dependence can be seen as a form of relationship or people addiction. It bears the hallmarks of other types of addictions, including emotional numbness or anesthetizing your feelings, chronic self doubt about your worth, chronic anger or frustration, a compulsive need to engage in the behavior, and the sense that you are never fulfilled, or that somehow it will never be enough to satisfy you. An incredible website for a discussion about co-dependency and people addictions can be found here: http://www.nmha.org/go/codependency