Homeless despite Yale degree; mental illness? drug addiction? choice?

Medical use of prescription drugs is rarely the primary reason anyone starts using heroin. Lifetime marijuana use(AOR 2.44), major depression or anxiety(OR 4.43), familial history of drug/alcohol abuse(OR 7.89 ), and PTSD(OR 8.68) are all stronger predictors of opioid abuse than being given an opioid prescription(OR 1.33).

https://www.fda.gov/media/107789/download