There are certain diseases which cause 'brain fog' that could give insight into trade offs of gaining/losing intelligence. I'm cold (literally, often less than 96 degrees) and it effects my cognition at times. The drop in IQ is probably much greater than 1 point. Personally I would do anything short of violence to prevent it.

Interestingly certain quantities of alcohol seem to increase my intelligence, mostly in areas I normally suffer in (like word recall, especially in a foreign language).