As a neuroscientist, I can say first hand that my study on drugs has led me to about the same conclusion.

Alcohol is the most harmful substance aside from Heroin...and even then, I'd say that Alcohol is worse than heroin in many ways.

1. People are not generally violent under the influence of diacetylmorphine (heroin) in fact, they are generally the opposite (peaceful).
2. Society is completely intolerant of heroin, and entirely tolerant of alcohol.
3. Alcohol is used in almost every social situation - beginning with college students (kids who are just emerging into adulthood and out of the house for the first time are welcomed into the world with a social expectation to learn to be intoxicated so that one can "get a better perspective of the world"...)
4. Alcohol causes people to be violent, have affairs, numb guilt and empathy. It lowers inhibition causing people to do and say things they would never have considered saying or doing otherwise.
5. Alcohol kills people directly and indirectly. It's addicting. It's difficult to stop for many people.
6. Need I say more?