This is a very interesting question... although it smells like a homework question... however, I'm not a pharmacist, but a psychologist interested in health issues, so take my answer with a grain of salt.
Psychology and medicine interact in many ways. There is the whole issue of patients taking their medication - either too much of it (addictions, such as to pain meds), or noncompliance (refusing to take it or adjusting the dosages themselves). There is also a HUGE issue of patients not being educated about their medications, especially the elderly and the chronically ill who may take many different kinds of medications (polypharmacy). Some people can barely read or understand their medication directions - they may be of a different culture (with their own set of beliefs about health and meds) or they may not have the literacy skills or their doctor(s) did not take the time to explain their meds properly - studies have been done on this. In addition, medications cause side effects, which may or may not lead to people to comply with or adjust or discontinue their meds - often without telling their doctor. There is the issue of alternative medicines and what people believe about them which then results in certain types of behaviors. And finally, there is the whole health care system in general being so fragmented - I mean, the whole idea of going to the doctor and then going to a pharmacy to get meds - when some people don't understand why they are taking them in the first place or have serious reservations that they were too intimidated to talk to their doctor about, etc. I mean, look at the psychology or mental health section of YA and see how many people question meds and have not talked to their doctor about it...
Anyway, as you can see, this is a very complicated issue...I'd like to know other people's opinions as well.
