I have a lot of experience (20+ yrs) working with troubled kids and their parents (if they’re even in the picture). I’ve worked closely with RTCs (residential treatment centers), the court system, psychologists, psychiatrists, and many other resources whose collective goal is to help troubled children grow into capable adults. Most of the kids I’ve worked for have gut-wrenching histories. I have a perspective that most do not, because it’s just not something we like to get up close and personal with or discuss with any depth.
The formative years of life are so important for establishing order, trust, cognitive development, etc. It’s the foundation that we build upon for life. Some have a shitty foundation and will struggle their whole life. Add in brain injury...well, good luck.
The movie Three Identical Strangers sheds some light on the nature/nurture topic.
The fields of psychiatry/psychology have far more questions than answers.
Unfortunately, many of the kids I’ve worked for were simply medicated into stupor because natural methods were ineffective. We just don’t understand what we’re dealing with. Considering how closed off (untrusting) many troubled kids are, how could we know?