Ethan Russo, MD, Senior Medical Advisor at the Cannabinoid Research Institute, wrote in a Dec. 2, 2001 email to

“In her review of cannabis and addiction (1997), Mathre found a low risk. She cited a New York Times article [Aug. 2, 1994, p.C3] in which Jack Henningfield of NIDA and Neal Benowitz of UCSF rated addictive symptoms of cannabis vs. other commonly used drugs including heroin, alcohol and cocaine. Overall, to summarize, she said [p. 179] ‘Marijuana was ranked lowest for withdrawal symptoms, tolerance and dependence (addiction) potential; it ranked close to caffeine in the degree of reinforcement and higher than caffeine and nicotine only in the degree of intoxication.’

Even in cases of high daily intake, such as the 94-day cannabis study (Cohen 1976), any withdrawal symptoms on its sudden cessation were transient and mild.

All four of the Missoula Chronic Use study patients occasionally found themselves without cannabis medicine. None have ever experienced any withdrawal symptoms, but rather, merely an increase in symptoms that cannabis treated for them.”

Dec. 2, 2001