The Diagnostic and Statistical Manual of Mental Disorders (DSM) is the yardstick that mental disorders are measured against. But every disorder in this reference guide is meant for individuals, because that’s how doctors diagnose diseases and disorders.
So it would be ground-breaking if the working groups that are focused on revising the DSM suddenly decided that a disorder could be diagnosed not just in an individual, but in a set of people — such as two people in a particularly unhealthy romantic relationship (Co-dependency Disorder?) or family (Scapegoating Disorder?).
This is exactly what some folks wanted to do to make their paydays easier in divorce court. The proposed disorder? Parental alienation disorder. Its “symptoms?” When a child’s relationship with one parent is poisoned by the estranged parent.