I'm quite certain some feelings of isolation will be formed, since perhaps some of the people we know may think we're not "like them", with our own 'different' ideals and perspectives. I highly doubt it will cause depression, though the only possible way related, is if the isolation gets a bit too much to handle. Since there's a lot of stuff that the intelligent individual observes, and wants to learn, I don't think there is much room for depression to come in. Just my opinion :D

I remember in Sociology class being warned of reaching incorrect cause and effect like there are more storks in the country than in the city, and people in the country tend to have more children, but that does not mean storks bring babies.

I think it is similar with intelligence and depression. One thing that I think contributes to depression is a more sedentary lifestyle, and people who are intelligent on average are more likely to have jobs that do not involve lots of physical activity.

yes, because you'll be so smart you'll drift from your friends and the world to follow your own path...and even though on your way they'll be others like you there all isolated as well.

I don't think intelligence causes depression and isolation but it can certainly lead to it.

ignorance is bliss.. intelligence plus oppression causes depression.. not just intelligence alone

Intelligence (or lack thereof) doesn't cause depression, but it does however increase the risks of it.

No because I don't drift from my friends I don't have very many of them because of there simple minded idiocy

Yes baby doll it can because you over think things you don't keep it simple

yes cause you think a lot of things

yes, so smart that you cant find people with the same intelligence.

That would fall more into social/psychological dysfunction

Intelligence can cause that, but it can also cause very good things.

Yeahh it sadly soes