ANd I was relating my personal experience as well, YYZ. The author of your study admits that her findings are “controversial.” Indeed they are, as the virtual consensus is that the drug is NOT physically addictive. An example:
http://www.spencerrecovery.com/marijuana-addiction.html
OK, here’s some more:
http://www.hopkinsmedicine.org/press_releases/2008/01_24_08.html
http://www.webmd.com/mental-health/news/20080507/withdrawal-symptoms-from-smoking-pot
http://www.marijuanapassion.com/Marijuana-Withdrawal.html
http://www.sciencedaily.com/releases/2008/01/080124145015.htm
http://www.cbsnews.com/stories/2008/05/08/health/webmd/main4080584.shtml
http://www.webmd.com/mental-health/news/20080130/pot-tobacco-withdrawal-equally-rough
And here’s a big long thread, if you’re interested, of anecdotal reports from people who are or have experienced withdrawl symptoms after prolonged, heavy pot usage.
http://hubpages.com/hub/Marijuana-withdrawal-symptoms-Insomnia—anxiety—iritability—headache