Question: How do I tell a friend that they have a substance abuse problem?
Before addressing your friend about this issue at all, it is really important that you are completely sure your friend has a substance abuse problem. This is a serious matter, so researching signs and symptoms before confronting your friend is probably a good idea. No drug use is good, but there is a difference between use and abuse.
After you have done your research, confronting your friend will be the hard part. I think it is best to address their drug abuse head on and not to dance around the issue. This is awkward and hard to do, but you wrote into Her Campus Colby for advice, so you clearly care about your friend very much. Getting over the awkwardness of the situation shows how much you care about this person and is really the best way to help them get better.
You can invite your friend over, maybe even order in food, and tell him/her there is something on your mind. Start by saying you care about them very much and that you are not accusing them of doing anything wrong (they will likely get very defensive so this is a necessary step), but that you have noticed a concerning pattern of drug use. If they walk out and choose to not continue the conversation, either wait for them to initiate the conversation again, try and bring it up again yourself, or let it go. Unfortunately, you can’t make someone accept your help, no matter how much they need it. If they stay and hear you out, mention some times you have noticed this abuse, give specific examples from your research that lead to your suspicion of a substance abuse problem, and reassure them that you are there to help.
Substance abuse is a scary issue but as a friend it is your job to stand by them no matter what. Good luck and good work!