I recently watched Netflix documentaries on the investigation of cold case murders in Los Angeles and New York City. in one, two teenagers from affluent families were convicted of murdering a middle-age man in Manhattan's Central Park, they later receiving the shockingly brief prison sentence of six years and serving half before being paroled. Thereafter, the girl was returned to prison to serve out her remaining sentence after she assaulted a fellow-parolee in their half-way residence while the boy remained out of trouble. No motive was ever established for the boy's vicious knife attack and the girl's complicity except rage.
While both their families had been caring, the girl had been adopted, which is a risk factor if the child is past infancy when adopted, and the boy had been a loner and shy. She had been in numerous drug treatment programs and both attended excellent schools. This raising the issue of whether, even given the best of treatment, their lives would have been different.
Change through therapy depends on the depth of psychological problems, the talent of therapy provided and its length. Luck too is a factor: had the youths not been drinking in Central Park that evening the murder might never have occurred. Which is why therapy is best provided in early childhood, before the stresses of adolescence and adulthood are encountered and lives are wasted.