Should I confront a friend or family member who I think is an addict ?

You can if you think that will help, but try to be cautious about it, dont just outright call them an addict, say that you notice (whatever their possibly addicted to) is seemingly starting to affect their life a lot and that you've been seeing changes you're not sure are beneficial to them.

That is entirely up to you. However, I would say if you are really worried about this person it may be a good idea just to make sure that they are alright.

You should talk to them, but not confront. Ask them if they need help and let them know you're concerned about them, but don't try to force them to quit.

Yes you should .... But be cautious in what you have to say to them and lightly bring up the topic in the discussions..... It will help if they are willing to open up so that you will be able to help them

You can, but I'd be careful in the way you approached them. You cannot control their behavior - you can let them know you're concerned, let them know if their behavior affects you, and let them know if the behavior continues you cannot allow them in your life any more, but you can't force them to seek help.

You should not confront them in terms of a confrontational approach. You should however address your concern with them. This means instead of confronting them harshly, for instance "You are screwed up for taking drugs", rather shift the focus to yourself, "I am concerned about you because some of your behavior lately has not seemed to fit into who I know you to be, can we talk about what is going on?". Provide the space where they can open up honestly without feeling judged for it, and them help them move forward to find avenues of recovery.

Confront in a polite manner, or confront a family member who is close to said member you're worried about

If it is affecting their life, others, or their well-being, then yes. Many addicts do not realise that they are addicted ('I can stop whenever I like' mentality). If they truly need help then helping them recognize that will go a long way in aiding their recovery.

Let them know that you're always there for them for support, let them feel comfortable with talking to you. Don't be too harsh or judgemental. If you feel that they're at risk, talk to higher authority like help centres or police.

Yes, you should. If you're concerened about their behaviour you should bring it up and at least have a conversation with them.

talk to them, definitely, but confrontation tends to have a negative connotation. You should not come at them in an angry or accusatory way because that may only make them defensive and drive them further into denial or pulling away from you. Instead, keep your tone gentle and understanding- you want to sound like you want to help them, not judge them. let them know you are worried and you only want what is best for them. if they are in denial or still refuse to stop, then you may have to move on to setting boundaries.

If you believe that they have a problem you can confront them and let them know that you're worried. However sometimes doing so makes the person very defensive so if you think they may do that have someone else there with you