I've seen it, too.
Wounds that time won't heal
https://www.dana.org/article/wounds-that-time-wont-heal/
" … early maltreatment, even exclusively psychological abuse, has enduring negative effects on brain development. We see specific kinds of brain abnormalities in psychiatric patients who were abused as children. We are also beginning to understand how these abnormalities may account directly for the personality traits and other symptoms that patients manifest."
"Physical, sexual, and psychological trauma in childhood may lead to psychiatric difficulties that show up in childhood, adolescence, or adulthood. The victim’s anger, shame, and despair can be directed inward to spawn symptoms such as depression, anxiety, suicidal ideation, and post-traumatic stress …"
" … borderline patients may shift rapidly from a logical … left-hemisphere state to a highly negative, critical, and emotional right hemisphere state.
… Very inconsistent behavior of a parent (for example, sometimes loving, sometimes abusing) might generate an irreconcilable mental image in a young child. Instead of reaching an integrated view, the child would form two diametrically opposite views—storing the positive view in the left hemisphere, the negative view in the right. These mental images, and their associated positive and negative world views, may remain unintegrated, and the hemispheres remain autonomous, as the child grows up."
Arrested Psychological Development and Age Regression
https://childhoodtraumarecoverydotcom2.wordpress.com/2013/10/13/arrested-psychological-development-and-age-regression/
"One of the main traumas a child can suffer is a problematic early relationship with the primary care- giver; these problems can include the primary care-giver having a mental illness, abusing alcohol/drugs, or otherwise abusing or abandoning the child. In such cases, attachment disorder is likely to occur in the child – this disorder can impair or even cripple a child’s ability to trust and bond with others. In such cases, it is the child’s ability to attach to other human beings which is impaired by developmental delays.
Since such a child’s development has essentially become frozen in relation to his/her ability to bond with others, s/he will not ‘grow out’ of the problem behaviours associated with attachment disorder without a great deal of emotional ‘repair work.’