Dr. Douglas Darnall in his book Divorce Casualties: Protecting Your Children from Parental Alienation, describes three categories of PA:
The mild category he calls the naïve alienators. They are ignorant of what they are doing and are willing to be educated and change.
The moderate category is the active alienators. When they are triggered, they lose control of appropriate boundaries. They go ballistic. When they calm down, they don’t want to admit that they were out of control.
In the severe category are the obsessed alienators or those who are involved in PAS. They operate from a delusional system where every cell of their body is committed to destroying the other parent’s relationship with the child.
In the latter case, he notes that we don’t have an effective protocol for treating an obsessed alienator other than removing the child from their influence.
An important point is that in PAS there is no true parental abuse and/or neglect on the part of the alienated parent. If this were the case, the child’s animosity would be justified. Also, it is not PAS if the child still has a positive relationship with the parent, even though one parent is attempting to alienate the child from him or her.