In a move that could radically change the definition of mental illness, mental health professionals have proposed that problematic relationships be labeled a type of disorder. The next edition of the Diagnostic and Statistical Manual (DSM), the profession's official handbook, may include relational disorders: dysfunction that arises due to interpersonal problems.

Michael First, M.D., an associate professor of clinical psychiatry at Columbia University and editor of the most recent edition of the DSM, explains that in these disorders the interaction itself is the illness. "It's traits that combine in a very negative way," he says. "Neither person is disordered per se."

This conceptual shift is problematic for some researchers, including Steven E. Hyman, M.D., former director of the National Institute of Mental Health. "It's a huge philosophical step that I don't consider warranted," he says. Instead of defining the relationship as dysfunctional, Hyman says such disorders could be explained as being present in individuals, but only in specific contexts.

Hyman also worries that the new category could be problematic in instances of child and spousal abuse.

"Defining a disorder in terms of a relationship instead of an individual puts a victim of abuse on the same level as their abuser," argues Hyman.

Luckily, psychiatrists have some time to wrestle with this issue: The next DSM is scheduled for publication around 2010.