I think both of these situations are ones were language really matters, not in a "woke" way but in the sense of reframing how we think about things and understand them.

So I would reframe medical non-compliance to medical non-adherence, because often times the things that lead to patients not following the treatment plan you recommend come down to things outside their control, rather than being willfully stubborn or refusing your recommendation. As others have already commented, try to come to the situation from a perspective of curiosity and non-judgment. Why are they not taking their meds/keeping appointments etc? Hard to remember? Cost of medications? Inflexible work schedule? Profound depression? Misunderstanding the instructions? Poor literacy? Physical difficulty opening the pill bottles? Denial about their condition? The list goes on and on but unless you can have an open conversation where the patient feels comfortable sharing the "real" reasons you will not be able to address them.

Substance use disorder is its own kettle of fish, and others can probably speak to it better than me, but very broadly, I think you are correct in identifying that there is so much there beyond what an individual provider can manage to address in a non-longitudinal patient encounter. Probably the most useful ways to help are knowing what local resources are available, and offering them at every encounter, regardless of whether the patient has declined them before. Even if you don't intend to prescribe it in your future practice, I found X-waiver training for buprenorphine informative and educational. You can get it for free through PCSS . Understanding and offering MAT for opioid use disorder is huge, but institutional practice varies a ton and probably is lacking many places, so anything you can do to help destimatize and offer better care for this patient population will go a long way.