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Difficulties in emotion regulation are commonly reported among individuals with alcohol and drug addictions and contribute to the acquisition and maintenance of addictive behaviors. Alterations in neural processing of negative affective stimuli have further been demonstrated among individuals with addictions. However, it is unclear whether these alterations are a general feature of addictions or are a result of prolonged exposure to drugs of abuse. To test the hypothesis of altered negative affect processing independent of drug effects, this study assessed neural function among drug-naïve youth with a behavioral addiction-Internet gaming disorder (IGD). Fifty-six young adults (28 with IGD, 28 matched controls) participated in fMRI scanning during performance of a well-validated emotion regulation task. Between-group differences in neural activity during task performance were assessed using a whole-brain, mixed-effects ANOVA with correction for multiple comparisons at currently recommended thresholds (voxel-level p<0.001, pFWE<0.05). Compared to controls, youth with IGD exhibited significantly blunted neural responses within distributed subcortical and cortical regions including the striatum, insula, lateral prefrontal cortex and anterior cingulate in response to negative affective cues, as well as during emotion regulation. Independent component analysis (ICA) further identified between-group differences in engagement of a fronto-cingulo-parietal network, involving decreased engagement in IGD youth relative to controls. Study findings are largely consistent with those from prior neuroimaging studies in substance-use disorders, thus raising the possibility that neural processing of negative affect may be blunted across drug and behavioral addictions independent of acute or chronic drug effects.

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Purpose of review: Neurobiological studies of tobacco/nicotine use examining genetic, molecular, functional, and behavioral correlates have improved our understanding of nicotine/tobacco dependence and have informed treatment. Recent work extending previously established findings and reporting novel methodologies and discoveries in preclinical and human studies are reviewed. Recent findings: Recent work in preclinical models has focused on the differential roles of nicotinic receptor subtypes and nicotine’s effects on neural systems beyond cortico-striatal dopaminergic pathways, and utilizing advanced methodologies such as pharmacogenetics, optogenetics and rodent fMRI to identify targets for treatment. Likewise, human neuroimaging studies have identified molecular and functional dynamic shifts associated with tobacco/nicotine use that further inform treatment. Summary: Nicotine/tobacco use is associated with widespread neural adaptations that are persistent and function to maintain addiction. The continued identification of genetic, molecular, neural, and behavioral endophenotypes related to nicotine/tobacco use, dependence, and addiction will facilitate the development and delivery of personalized treatment.

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Group decision-making is common in everyday life, whether a family is sharing a meal or a corporation is dividing profits. Research in economics on group decision-making has coalesced into a theory known as the tragedy of the commons, which states that resources are inevitably overused when shared by a group. However, even while multiple approaches to mitigating overuse of common resources have been put forward, notable counterexamples to the tragedy of the commons exist such that groups are ultimately able to avoid resource overuse. Development of a computerized paradigm amenable to behavioral modeling and simulation analyses could allow for exploration of whether resources will be overused in a given group of individuals and allow for the rapid testing of behavioral interventions designed to reduce instances of resource overuse. Using a newly developed group decision-making task, we studied how participants made decisions to utilize shared resources for the potential to receive a larger amount of money or conserve resources for a smaller amount of money. Using behavioral modeling, we found that valuation of resource overuse is most impacted only when an exceptionally small amount of resources are remaining. Using computational analyses, we were able to differentiate individual participants by both group earnings and self-reported social attitudes in ways that correlated with their willingness to utilize resources. These results signify the importance of individual differences in group composition regarding the tragedy of the commons, emphasizing the impact of the attitudes and behaviors of individual group members in predicting shared resource use.