I know that perpetual hurt can cause someone to jump to the reaction that will make them feel strongest in that particular situation; it's a little concerning because it could mean that so much damage has been done up front, Sarah has absolutely no faith in her mother to look out for her best interests.  In all honesty, both mother and daughter should be sitting down for therapy so that they can resolve their differences before it becomes anymore toxic to their relationship.

Sorry to soapbox, but I really do feel for the mother; she may not be as supportive of her child as she could be, but this is a parent that has proven over and over that she will do whatever she believes is necessary to protect her child from any harm that she can perceive - and while this has many times lead to her being the source of hurt, she truly believes that she is shielding Sarah from greater harm.  Sadly, this places her in an optimal position to be taking the punishment from both sides of any conflict because her daughter sees her to be as bad, if not worse than those that are actually attacking her, and is more likely to lash out at her mother.