Comment Re:Or maybe... (Score 2) 365
But potentially true. An imbalance in the endocrine system, perhaps, that leads to seeking what nicotine gives you. This would hardly be unknown (eg. seeking sugar in preference to other food can be caused by low thyroid; a midlife shift to vegetarianism is associated with low estrogen in women). Likely doesn't initiate smoking, but may well be why some people just can't quit.
Also, there are parasites that cause behavior changes in their hosts, tho that's an unlikely cause in humans.