Funnily enough, I was talking about this exact topic with a clinical psychologist recently. In a nutshell, intelligent people think more. They don't just thin

Funnily enough, I was talking about this exact topic with a clinical psychologist recently. In a nutshell, intelligent people think more. They don't just think better, or more efficiently, they think more. The side-effect is that certain illnesses like depression affect intelligent people quite hard. They self-medicate, often with alcohol. As well, otherwise healthy intelligent people might self-medicate to calm down their perceived over-active thoughts. Combined, the result is that intelligent people are over-represented in alcoholism, albeit perhaps as high-functioning alcoholics.