I've heard it described as being similar to brainwashing because it wears away one's self-confidence and their sense of self. Emotional abuse doesn't just suddenly happen, and then just as abruptly, stop. It's a behavioral patter that occurs over a period of time. Women who have been emotionally abused as children often find themselves in abusive relationships as adults. Doctors agree that those who experience emotional abuse usually come from abusive families.
Emotional abusers have a tendency to push their limits.
They will go as far as their partner will allow. When they learn their partner will no longer allow it, some will back off. Others may try different tactics. Still, it is worth the risk. Many emotional abusers have been indoctrinated with their behavior to the point that they don't even know they are being abusive.