You are correct in using caution when mixing cannabis with pharma meds. That doesn't mean that you shouldn't do it, just that you must be careful. We have both a pharmacist and medical doctor on staff and they would be happy to answer any of your questions. If you send a detailed email to firstname.lastname@example.org I will forward your questions to our pharmacist and we will get back to you.
I do agree with @Dneice about caution being applied when using cannabis in conjunction with prescription meds for depression. I always warn my patients to be careful or to try to avoid if possible co-admnistration of med cann w/ benzodiazepines, other sleep aids, anti-convulsants as this may increase risk of fall or accident. However, that being said, many of our patients are safely taking med cann along w/ SSRI's like Lexapro, Prozac, that are used for depression. Let your mental health professional know you are using med cann, avoid daily use of cannabis (increases psych dependency risk esp if depression or anxiety is involved 20%+ in some studies) and make sure you are involved in behavioral therapy if it's offered. I hope this helps!