Glutamate signaling plays a major role in addiction. Preclinical research strongly suggests an implication of G-protein-coupled metabotropic glutamate receptor subtype 5 (mGluR5) in nicotine addiction and alcohol use disorder. In humans, smoking is related to a global reduction in mGluR5 availability. In the present study, we investigated mGluR5 in vivo in patients with alcohol use disorder without the confounding effects of smoking. A total of 14 male subjects with alcohol use disorder and at least a 25-day abstinence and 14 matched male non-smoking healthy controls were included in the study. We employed positron emission tomography (PET) with the mGluR5-specific radiotracer [11C]ABP688, using a bolus/infusion protocol. We found increased mGluR5 DVR in several regions within the temporal lobe in patients, as compared to controls. The largest between-group difference was in the amygdala. There was a marked positive relation between mGluR5 DVR in the anterior cingulate and mGluR5 DVR in the orbitofrontal cortex in patients, but not in controls. In patients, lower temptation to drink was related to higher amygdala mGluR5 DVR. We did not find altered mGluR5 DVR in the basal ganglia of subjects recovering from alcohol use disorder. In conclusion, our study provides clinical evidence for altered mGluR5 signaling in the amygdala in alcohol use disorder. This alteration was associated with the temptation to drink. In addition, this study suggests abnormal mGluR5 signaling in a network underlying reward-related behavioral flexibility. These findings strengthen the case for pharmacological agents acting on mGluR5 as promising candidates for the treatment of alcohol use disorder.

Background: Changing addictive behavior is a complex process with high demands on motivation. The Transtheoretical Model of Behavior Change provides a theoretical framework for explaining and predicting behavioral change, although its predictive value for addiction is somewhat inconsistent. Objective:The aim of the present study is to extend the Transtheoretical Model of Behavior Change by investigating not only treatment motivation but also the predictive value of the type of drinking-related treatment goal. Additional predictors, such as substance-related and sociodemographic variables, are also included in analyses seeking to predict return to drinking during relapse prevention treatment for alcohol use disorder. Methods:In this observational study, 99 inpatients from a treatment center for alcohol use disorder were recruited. Treatment motivation was assessed in accordance with the Transtheoretical Model of Behavior Change, drinking-related treatment goal through a self-report questionnaire, and substancerelated and sociodemographic variables via the clinic information system. Associations between the potential predictors and covariates were explored using stepwise logistic regression.Results: During treatment, 42.6% of participants had at least one relapse. Scoring higher on the action dimension at admission (OR = 0.81, p = .04) and being employed (OR = 0.37, p = .02) were significant predictors of abstinence during treatment. Conclusions:This study confirms that treatment motivation contributes to the prediction of treatment outcome, even when controlling for other variables. In future research, the underlying mechanisms of treatment motivation should be further explored.

No abstract

The role of alcohol-related risk perception for effective treatment of alcohol use disorders (AUD) is still unclear. The present study on 101 alcohol-dependent patients undergoing a 10-week AUD treatment protocol investigated the relationship between alcohol-related risk perception and alcohol use with the hypotheses that (1) risk perception changes across treatment, (2) changes vary with treatment-related experiences of abstinence/relapse indicating ‘risk reappraisal,’ and (3) adjustment of perceived own vulnerability according to ‘risk reappraisal hypothesis’ predicts abstinence during follow-up. Abstinence during treatment was related to a decrease, and relapse during treatment to a slight increase in perceived own risks. Abstinence during the 3-month follow-up varied with experience-induced risk reappraisal. The results show an impact of risk reappraisal on alcohol use and hence advocate a focus on risk reappraisal in AUD treatment.