While this is a good book this is not a settled issue and this book is not a full authority either. BPD is still largely still being understood and studies are still ongoing. Just like the common belief based on current study indicates childhood trauma however that's not a settled issue as to its origin and it's hard to understand what is trauma considering the fact that they interpret all rejection projection as trauma.

The emotional chemical effect is well understood in that their emotional response is too high. However they are given an unfair amount of sympathy and leeway considering the fact that people with PTSD also can develop problems with the amygdala and hypothalamus and are still considered responsible for their actions.

Everyone is considered responsible for their choices and actions regardless of their feelings. The very fact that there are people with BPD, although a minority, who choose to self-harm rather than harm others when they are overwhelmed and there are people that commit to DBT successfully is plenty of evidence of choice of behavior to those overwhelming emotions. It should also be pointed out how many self aware people there are with BPD on the internet who do not care about their effects on other people on the much as they want to be catered to sympathized with.

Plenty of things make my mother happy they are just fleeting and some of them involves sadism. It's just like addiction where they have chemical problems that they did not choose but they are aware of their effects on other people and they are responsible for accepting treatment.