Childhood depression may lead you to develop smoking habits in future. According to Dr. Solja Niemela of the University of Turku in Finland, one of the researchers, childhood depression may lead to the twenty per cent increased risk of being a habitual smoker. It may also lead to forty per cent increased risk of becoming a heavy tobacco user by the age of 18. The researchers has affirmed following the study that childhood hyperactivity and conduct problems are the two factors which are well known linked with adult smoking. However, this study is among the first to disclose link between childhood depressive symptoms and subsequent smoking.