Chronic alcohol consumption, abstinence and relapse: brain proton magnetic resonance spectroscopy studies in animals and humans.

This chapter summarizes the peer-reviewed literature of proton magnetic resonance spectroscopy ((1)H MRS) studies on the effects of chronic and excessive alcohol consumption in both the animal and human brain. After a brief summary of the neuropathology of alcohol use disorders (AUD), we describe the primary brain metabolites measured by in vivo (1)H MRS. We then focus on published MRS studies of animal models of alcohol dependence and of treatment-seeking humans with AUD. We also summarize the scant MRS research on the much larger fraction of treatment-naïve individuals with AUD and the similarities and discrepancies relative to treatment-seekers. It is exceedingly apparent that premorbid and/or comorbid disorders/conditions, especially chronic smoking, among individuals with AUD contribute to the considerable variability in the pattern and magnitude of neurobiological and neurocognitive abnormalities in AUD. Therefore, we also review studies on the neurobiological consequences of the combined effects of chronic drinking and smoking in AUD. Finally, as AUD is characterized by a chronically relapsing/remitting course over lifetime and identification of those at greatest risk for relapse is important, we review (1)H MRS studies on brain spectroscopic measures that contribute to the prediction of relapse in AUD. We conclude with an overall assessment of the MRS research literature on brain alcohol effects, the role of animal and human studies in understanding the disease, and discuss the need of widely integrative MRS studies of cohorts that include individuals with comorbidies that are reflective of the general population with AUD.