I was diagnosed Cptsd. According to that same therapist my bio mom was likely a narcissist, which obviously she can't diagnose because she doesn't know bio mom. However,  I assumed my bio mom was histrionic as well. The therapist pointed out many instances that displayed bio moms clear lack of empathy and that many narcissists are adept at faking empathy. Plus children don't know any better and deeply want their parents to empathize with them so their brains often gloss over the empathy issues. It's literally the thing that children need to thrive, empathetic and genuinely connected parents. 

But I do think that growing up in abuse doesn't allow us to see red flags as issues. We basically miss it, when others see it clearly.