Almost all of my classmates (not me, unfortunately) were from exceptionally wealthy families and excepting one none of them ever mentioned any childhood trauma. Instead they were precocious partiers who got into drugs despite being underage and going to the nightclubs in the seedy part of town - no one at the time was turning away hot young women or gay(for pay or real) young men. And the club scene was a drug scene. It still is.
I don’t think trauma is actually at the root of almost all drug abusers. The only first class abusers (pot and alcohol in serious quantities daily) that I know at the moment grew up in perfectly fine suburban families and are in good, non-narcissistic/controlling/etc relationships with their families. They’re just addicts who can’t stop. One of them is going to die from it, eventually, given his level of alcohol consumption.