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When Drs. Vincent Dole and Mary Jane Kreek first pioneered the use
of methadone to treat opiate addiction in 1963, they postulated the
existence of underlying physiological disorder (“ a persistent
derangement of the endogenous ligand-narcotic receptor system”,
JAMA 1988) that was treated by methadone and that this was a matter
greater than simple substitution or replacement for illicit opioids.
Since that time, a great deal of scientific data has illuminated the
neurobiological basis for opiate addiction.

Recent data of particular interest are the results of PET scan brain
studies of humans with opiate addiction. Drs. Galynkar and Watras-
Ganz completed a preliminary PET scan study (2000) to determine if
there were persistent differences in brain function in individuals with
opiate addiction compared to individuals who do not have substance
abuse, and whether methadone maintenance treatment reduced or
reversed these functional abnormalities in the addicted individuals.
PET (positron emission tomography) scanning is an imaging tool that
evaluates brain function in different regions by measuring the glucose
metabolic rate in those regions. The results revealed a statistically
significant difference in glucose metabolic rate in the brains of
individuals with opiate addiction compared to individuals without
substance use problems. Additionally, the brain glucose metabolic
rate for opiate addicts who had undergone methadone maintenance
was intermediate between that of untreated opiate addicts, and
individuals without substance use problems.

Based on this data, the authors concluded that neurobiological
abnormalities (aberrations in brain function) must exist in the brain of
the opiate addict, which persist for several years even after methadone
treatment has concluded. Further research is needed to elucidate the
relationship between glucose metabolism rate in the brain, opiate use,
and the neuro-chemical abnormalities involved in addictive behavior.

These persistent changes were supported by another PET scan brain
study conducted by Drs. Daglish, Weinstein and colleagues from the
University of Bristol, United Kingdom. They used PET scans to