Methamphetamine use has been shown to cause abnormalities in brain regions associated with selective attention and regions associated with memory, according to background information in the article. Recent animal and human studies suggest that neuronal changes associated with long-term methamphetamine use may not be permanent but may partially recover with prolonged abstinence.
Thomas E. Nordahl, M.D., Ph.D., of the University of California, Davis, and colleagues compared eight methamphetamine users who had not used methamphetamine for one to five years and 16 recently abstinent methamphetamine users who had not used the drug for one to six months with 13 healthy, non-substance-using controls using a method of brain imaging, proton magnetic resonance spectroscopy (MRS), that allows the visualization of biochemical markers that are linked with damage and recovery to the neurons in the brain.
The researchers measured biomarkers in the anterior cingulum cortex, a region of the brain associated with selective attention. Levels of N-acetylaspartate (NAA), which is present only in neurons, were measured as a marker of the amount of damage (neuronal loss). Choline (Cho), which is generated by the creation of new membranes and, the authors write, "may be an ideal marker to track changes consistent with neuronal recovery associated with drug abstinence," was measured as a biomarker of recovery.
Levels of NAA were abnormally low in all the methamphetamine users, the authors found. Levels were lower relative to the length of methamphetamine use, but did not change relative to the amount of time that the methampheta
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JAMA and Archives Journals
4-Apr-2005