Can I tell what kind of hair loss by inspecting the hairs that are falling out?

[Rapido1234]

So I am in a predicament. I have noticed my black hair is losing darkness and getting thinner. A week ago I started shedding pretty nasty. I have been on finasteride for about 2 years now and It seemed pretty steady up until now. I want to blame the fin for losing effectiveness, but then I remembered that there are some other factors that might be responsible. For one, I began taking Adderall a few months ago and I started antidepressants 2 weeks ago. I also have lost about 20 pounds since I began adderall. I know these are all potentially things that could cause this. I assume that one week is not enough time for the antidepressant to cause any noticeable hair loss. The adderall on the other hand might have, either directly or indirectly. Not sure if I would be losing hair from telogen effluvium due to the medication itself, or my decrease in appetite and less eating (weight loss).

So, basically I want to know if there is a way to tell by looking at the hairs that are falling out or seeing where they are falling out from. Is there any way to rule out MPB? That is really my main concern right now.

Also, if this is due to the medication, will my hair grow back and adjust to the medication or will it continue to shrink?

Thanks!
(and sorry for going so detailed on my first post)