Addiction Study Finds People Underestimate Power Of Drug Cravings / Medical News Today, 16 February 2007
http://www.medicalnewstoday.com/medicalnews.php?newsid=62936
Jonathan Potts
"A novel experiment conducted by Carnegie Mellon University Professor George Loewenstein and colleagues may explain why people try a drug, such as heroin, for the first time despite ample evidence that it is addictive. The results of the study reveal that even longtime addicts underestimate the influence that drug cravings have over their behaviour."

Altered states: The impact of immediate craving on the valuation of current and future opioids
Journal of Health Economics, Available online 16 January 2007
http://digbig.com/4rmkf
Gary J. Badger, Warren K. Bickel, Louis A. Giordano, Eric A. Jacobs, George Loewenstein, Lisa Marsch [Sub required]