UK psychologist Aryanne Oade works with both workplace abusers and targets of workplace abuse and says in her "Recovery From Workplace Bullying" article that workplace abuse involves:

• The abuser taking away power from the target by limiting her behavioral choices and disregarding her boundaries.
• The abuser giving that power to herself.

This power dynamic sets the tone for their relationship and involves compliance on the part of the target, who is left feeling less than human and powerless. Eventually, the once high performing target's wellbeing, performance, and reputation greatly suffer.

The target's biggest challenge: to save her self-confidence
Targets struggle to remain objective about themselves both during and after bullying.

Some lose sight of who they are, what qualities they possess, what skills they have developed, and what they are good at doing. [They begin to believe that] they are useless or ineffective or won’t be happy again or...