s only a correlational study, so there is no proof of cause and effect, but all we know is that there is a link between the two things(
second hand smoke and behavioral problems). Though I wouldn't doubt that the chemicals in second hand smoke can alter a child's brain chemistry, which could easily lead to behavioral problems. If you google "effect of second hand smoke on children" you'll get many results about this topic. It is also posted on Webmd, among other sites.