<human>: Can you provide a brief overview of the text?

The Tuscon shooting story struck a cord with me, especially after reading the friends [description] of Jared Loughner's behavior before the incident.  I have a friend who as of recently:

1. Very interested in conspiracy theories that are implausible. 

2. Hasn't been talking to any friends as of late (3 weeks now)

3. Experiments w/ drugs (some psychedelics and pot.)  The conspiracy talk increases when he is high but he seems to hold most of the same views when high or sober.  I have heard from other people that he has had some very bizarre altercations with people related to the conspiracy talk when he was high, but it did not involve me so I cannot attest to any of that.  When I am around him, he seems fairly normal.  I have already made it clear to him I didn't enjoy hearing his "theories" and when I am around him to not talk about it.
      

There is more to it than this, but I don't want to get anymore specific right now. 

I also want to make clear that while he is a very confrontational person, he does not have a violent history or has never said anything to me that would make me assume he is planning on doing anything violent.   I just don't know if I should do anything.  Confronting him would seem incredibly difficult, plus I'm not entirely sure anything is really wrong (seeing that its been 3 weeks).  

Any advice?
<bot>: Have a friend who has some vaguely similar behavioral traits to the recent Tuscon shooter, and he has become increasingly distant from friends.  What should I do?