Hey Dom, I wouldn't worry about the people who complain about drug use in literature, because they are either closed minded, living in a bubble or a former addict that hasn't come to terms with it being portrayed in an objective light.
I think it would be rather remiss of any author who writes fiction with teen characters to not have any form of drug use in their works at some point, from what I've read over 50% of teens have tried illegal drugs, however I think it would be safe to say the number would more likely be around 60% or more. The stats I have seen which are a few years old (because I haven't found any new ones) would also show that 25% of teens use illegal drugs once a month, yet again I think that number is rather low and incorrect.
Many people have mentioned the consequences of drug use, outside of financial there are often none for recreational use, go to most clubs on a saturday night and likely half the crowd will have had some drug, the majority of them aren't addicts.....For every person who is an addict, there will be 10 who use drugs recreationally without addiction, so if you can distiguish between recreation and addiction then there is realism in your stories on the subject.
I think the way you have portrayed drug use is realistic, in TLW it was recreational, sitting around having fun and relaxing in a social way, in TOU Trina had issues she wasn't dealing with and tried to escape them by drinking heavily and regulary.
Safer sex requires condoms, lube, PEP (Post-Exposure Prophylaxis) if a condom breaks, regular blood testing if sexually active and the list goes on.....Not everyone will take those steps, you can't control what people do, you can try and influence them but yet again it comes back to realism....
As for unsafe sex in stories, I don't know what effect it has on younger guys, but I do know that the rate of unsafe sex is increasing, mainly due to young guys not seeing their friends dying in hospital like what happened in the 80's-early 90's. If young guys insist on unsafe sex then make sure it is an exclusive relationship (after sexual health testing) with a guy under 25, simply because the number of guys under 25 with an STD or HIV is really low compaired to those over 25, with those in the 30-50 range being the most HIV/STD infected group. I have no doubt someone over 30 will attack me for what i just said, but look at the facts.
I have also worked in the sexual health field so I do know what I'm talking about, however not everyone will practice safer sex all the time, so there has to be a multi-layered approach to it. I know that in relation to gay sex education in particular that school's have a lot to answer for, since they provide next to no information, I imagine it's worse in the US with that abstinence only nonsense.
That of any help Dom?