These stats are posted from
http://www.camh.net/News_events/Key_CAMH_facts_for_media/addictionmentalhealthstatistics.html
# One out of every 10 Canadians aged 15 and over, about 2.6 million people, reported symptoms consistent with alcohol or illicit drug dependence, or one of the five mental disorders covered in the survey, at some time during the 12 months prior to the interview. (Statistics Canada: CCHS 2003)
# The prevalence rate for substance dependence on alcohol and illicit drugs is much more common for men (4%) than for women (2%). (Statistics Canada: CCHS 2003)"
Personally, though, I see a range of 2-10% prevalence of addiction to illicit substances and/or alcohol, depending on their definition of addiction. I'd ballpark a guess that roughly 7-8% of the total population is predisposed to addiction, genetically or otherwise. I'd be interested to know what current research on addiction -- and specifically genetic predisposition to addiction -- have concluded with reasonable certainty. I think that many other types of addiction exist, as well... how about gambling? sex? food? video games? etc etc, but no one really puts those in the same class as alcohol/drugs. As far as addiction and steroids, that's a sensitive subject, here. Check out the diagram I uploaded, below (source is a British medical journal -- it's not JAMA, but likely a credible source). You can decide what to think for yourself, on that one. Any cross-linking between drug dependence and steroids? Possibly. I would think that it wouldn't be so much of a genetic addiction, since you don't really manipulate your sense of well-being to a great extent w/ steroids (think neurotransmitters, here... like what narcotics stimulants do in ref. to dopamine and norepinephrine, etc.). I think there are correlations between addiction and steroid use... but most likely it's a psychological addiction related to verified mental disorders such as body dysmorphic disorder, plastic surgery addiction (human ken doll, google it), and even depression. The majority of steroid users, I would think, just want to look good. The majority of steroid users are also middle-class guys with jobs, families, car payments, etc., that probably do not fit the typical "addict persona."