The ever-expanding list of so-called psychiatric conditions included in the American Psychiatric Association’s (APA) Diagnostic and Statistical Manual (DSM) may soon include “relational disorders,” or mental illnesses supposedly attributed to two or more people involved in a relationship together.

According to the official definition, relational disorders are “persistent and painful patterns of feelings, behavior, and perceptions involving two or more partners in an important personal relationship.” A married couple, for instance, that continually fights would constitute a relational disorder, as would a troubled parent-child relationship.

If recognized and included in the manual, relational disorders will be the first psychiatric condition that involves more than one person. It will also be the first condition that exists only between two or more people, and not in a single individual.