Interesting topic. I've noticed that as I get older I become a lot more susceptible to mood swings from substances as 'socially acceptable' as alcohol or nicotine even. In my youth I did all of the things and am glad of it now, but I could never go back to those days. I can't even drink a cup of coffee in the evenings anymore without having restless sleep...

Ironically, what I've always steered clear of is prescription drugs of any sort. Having seen my mum struggle for years with depression/anxiety (and subsequently turn into a zombie from the cocktail of pills she was taking at one stage) I've never trusted any of those substances. At the end of the day, whatever we take, legal or less so, is simply masking an inability to deal with reality (especially when it becomes habit).