Opposites attract

"The lifetime prevalence of alcohol dependence is 22% for individuals with any mental disorder compared to 14% for the general population, and the odds of having alcohol dependence if a person also has any mental disorder is 2.3 times higher than if there is no mental disorder."

I don't know how reliable this article is, but it's got footnotes, so I'm going with it. It's amazing the correlation between mental illness and addiction to any substances. Apparently, duh, abused substances can create psychiatric-like symptoms, which many people with mental illness seem to crave. Who doesn't like to be manic? Well, take some coke! And when you're depressed, somehow alcohol (a depressant) makes it better.

Perhaps, like some psychiatric drugs, the addictive drug has the opposite effect on mentally ill people than it does in the general population. Like Adderall, or Ritalin. They are uppers (prescription coke, basically) and docs give them to people who are manic or hyper-active and it calms them down. So something that would make most normal people manic, has the opposite effect on mentally ill folks.

I wonder if other substances work the same way?