Alcohol stress response dampening during imminent versus distal, uncertain threat

A shared threat-anticipation circuit is dynamically engaged at different moments by certain and uncertain threat

Temporal dynamics play a central role in models of emotion: "fear" is widely conceptualized as a phasic response to certain-and-imminent danger, whereas "anxiety" is a sustained response to uncertain-or-distal harm. Yet the underlying human neurobiology remains contentious. Leveraging an ethnoracially diverse sample, translationally relevant paradigm, and theory-driven modeling approach, we demonstrate that certain and uncertain threat recruit a shared threat-anticipation circuit. This cortico-subcortical circuit exhibits persistently elevated activation when anticipating uncertain-threat encounters and a transient burst of activation in the moments before certain encounters. For many scientists and clinicians, feelings are the defining feature of human fear and anxiety. Here we used an independently validated brain signature to covertly decode the momentary dynamics of anticipatory distress for the first time. Results mirrored the dynamics of neural activation. These observations provide fresh insights into the neurobiology of threat-elicited emotions and set the stage for more ambitious clinical and mechanistic research.

Neuroticism/Negative Emotionality Is Associated with Increased Reactivity to Uncertain Threat in the Bed Nucleus of the Stria Terminalis, Not the Amygdala

Neuroticism/negative emotionality (N/NE)-the tendency to experience anxiety, fear, and other negative emotions-is a fundamental dimension of temperament with profound consequences for health, wealth, and well-being. Elevated N/NE is associated with a panoply of adverse outcomes, from reduced socioeconomic attainment to psychiatric illness. Animal research suggests that N/NE reflects heightened reactivity to uncertain threat in the bed nucleus of the stria terminalis (BST) and central nucleus of the amygdala (Ce), but the relevance of these discoveries to humans has remained unclear. Here we used a novel combination of psychometric, psychophysiological, and neuroimaging approaches to test this hypothesis in an ethnoracially diverse, sex-balanced sample of 220 emerging adults selectively recruited to encompass a broad spectrum of N/NE. Cross-validated robust-regression analyses demonstrated that N/NE is preferentially associated with heightened BST activation during the uncertain anticipation of a genuinely distressing threat (aversive multimodal stimulation), whereas N/NE was unrelated to BST activation during certain-threat anticipation, Ce activation during either type of threat anticipation, or BST/Ce reactivity to threat-related faces. It is often assumed that different threat paradigms are interchangeable assays of individual differences in brain function, yet this has rarely been tested. Our results revealed negligible associations between BST/Ce reactivity to the anticipation of threat and the presentation of threat-related faces, indicating that the two tasks are nonfungible. These observations provide a framework for conceptualizing emotional traits and disorders; for guiding the design and interpretation of biobank and other neuroimaging studies of psychiatric risk, disease, and treatment; and for refining mechanistic research.

Altered effective connectivity during threat anticipation in individuals with alcohol use disorder

BACKGROUND

A developing theory and recent research suggest that heightened reactivity to uncertain stressors or threats may be an important individual difference factor that facilitates excessive drinking as a means of avoidance-based coping and characterizes individuals with current and past alcohol use disorder (AUD). Neuroimaging studies of unpredictable threat processing have repeatedly demonstrated activation of the anterior insula (AIC), anteromedial (AM) thalamus and dorsal anterior cingulate cortex (dACC). The present study aimed to understand how these three regions function as a network during anticipation of unpredictable threat (and predictable threat).

METHODS

Participants were 43 young adults (aged 21-30) with AUD and 26 healthy controls. Functional magnetic resonance imaging and dynamic causal modeling were used to study inter-regional effective connectivities and predictable and unpredictable threat-related modulations thereof within this network. Parametric empirical Bayesian modeling was used to conduct between-group comparisons in effective connectivities.

RESULTS

During unpredictable threat trials, the increased projection from the right AM thalamus to the right AIC was significantly present only in the AUD group. This directional influence was stronger among individuals who on average consumed more drinks per week. As expected, we found no group differences in modulatory changes to effective connectivities during predictable threat trials.

CONCLUSIONS

To our knowledge, this is the first study to examine directional interactions between key frontolimbic regions during anticipation of unpredictable and predictable threat and demonstrate the importance of 'bottom-up' thalamic-insular projections during unpredictable threat processing in AUD. Prospective studies are warranted to determine whether this association may be causal.

In the anticipation of threat: Neural regulatory activity indicated by delta-beta correlation and its relation to anxiety

The anticipation of oncoming threats is emotionally challenging and related to anxiety. The current study aimed to investigate the neural regulatory processes during the anticipatory preparations in stressful situations in relation to trait anxiety, especially in an uncertainty-related stressful situation. To this end, we measured within-subjects delta-beta amplitude-amplitude correlation (AAC) and phase-amplitude coupling (PAC) with electroencephalography using a well-defined stress-inducing paradigm in 28 high-trait-anxiety (HTA) and 29 low-trait-anxiety (LTA) college students. Specifically, a threat probability task was conducted, where participants anticipated the future stimuli under the uncertain (i.e., an average of 50% electric shocks), certain (i.e., 100% electric shocks) and no threat conditions, as well as a resting state task. Results showed a generally larger delta-beta AAC in the LTA group relative to the HTA group across conditions, supporting the hypothesis that delta-beta AAC reflects the efficiency of stress regulation and trait anxiety could compromise this adaptive regulatory activity. Furthermore, a larger delta-beta PAC was found under the uncertain threat condition relative to the no threat condition, indicating the sensitivity of delta-beta PAC in reflecting state anxiety. These findings indicate that while delta-beta AAC is more related to trait anxiety and could distinguish between high and low trait anxiety irrespective of conditions, delta-beta PAC is more related to state anxiety and is sensitive enough to detect the uncertainty-related anxious state.

Sleep quality impacts the link between reactivity to uncertain threat and anxiety and alcohol use in youth

Individual differences in reactivity to unpredictable threat (U-threat) have repeatedly been linked to symptoms of anxiety and drinking behavior. An emerging theory is that individuals who are hyper-reactive to U-threat experience chronic anticipatory anxiety, hyperarousal, and are vulnerable to excessive alcohol use via negative reinforcement processes. Notably, anxiety and alcohol use commonly relate to disruptions in sleep behavior and recent findings suggest that sleep quality may impact the link between reactivity to U-threat and psychiatric symptoms and behaviors. The aim of the current study was to examine the unique and interactive effects of reactivity to U-threat and sleep quality on anxiety symptoms and drinking behavior in a cohort of youth, ages 16-19 years. Participants (N = 112) completed a well-validated threat-of-shock task designed to probe individual differences in reactivity to U-threat and predictable threat (P-threat). Startle eyeblink potentiation was recorded during the task as an index of aversive reactivity. Participants also completed well-validated self-report measures of anxiety and depression symptoms, lifetime alcohol use, and current sleep quality. Results revealed significant startle reactivity to U-threat by sleep quality interactions on anxiety symptoms and lifetime drinking behavior. At high levels of sleep disturbance (only), greater reactivity to U-threat was associated with greater anxiety symptoms and total number of lifetime alcoholic beverages. These results suggest that sensitivity to uncertainty and chronic hyperarousal increases anxiety symptoms and alcohol use behavior, particularly in the context of poor sleep quality.

The interactive effects of different facets of threat uncertainty and cognitive load in shaping fear and anxiety responses

A large body of research indicates that exaggerated response to uncertainty of a future threat is at the core of anxiety and related disorders, underscoring the need for a better understanding of the underlying mechanisms. Although behavioral and neuroimaging studies have suggested a close relationship between uncertainty responses and cognitive control, little is known about what elements of uncertainty are more or less vulnerable to cognitive modulation in shaping aversive responses. Leveraging a novel paradigm, an n-back working memory task embedded within a modified threat-of-shock paradigm, we examined how the influences of different facets of uncertainty (i.e., occurrence and timing) on psychophysiological responses were modulated by cognitive load. Psychophysiological responses were assessed using the acoustic startle reflex. Replicating prior work, the effects of cognitive load and temporal unpredictability of threat on startle responses were evident. The effect of occurrence unpredictability appears to depend on other factors. Under low cognitive load, startle response was potentiated when both the occurrence and the timing of threat were predictable. Under high cognitive load, startle response was significantly reduced, especially when a threat context involves uncertainty in both temporal and probability domains. These observations provide a framework for refining the model of fear and anxiety and for understanding the etiology of psychological disorders characterized by maladaptive uncertainty responses.

Acute nicotine abstinence amplifies subjective withdrawal symptoms and threat-evoked fear and anxiety, but not extended amygdala reactivity

Tobacco smoking imposes a staggering burden on public health, underscoring the urgency of developing a deeper understanding of the processes that maintain addiction. Clinical and experience-sampling data highlight the importance of anxious withdrawal symptoms, but the underlying neurobiology has remained elusive. Mechanistic work in animals implicates the central extended amygdala (EAc)-including the central nucleus of the amygdala and the neighboring bed nucleus of the stria terminalis-but the translational relevance of these discoveries remains unexplored. Here we leveraged a randomized trial design, well-established threat-anticipation paradigm, and multidimensional battery of assessments to understand the consequences of 24-hour nicotine abstinence. The threat-anticipation paradigm had the expected consequences, amplifying subjective distress and arousal, and recruiting the canonical threat-anticipation network. Abstinence increased smoking urges and withdrawal symptoms, and potentiated threat-evoked distress, but had negligible consequences for EAc threat reactivity, raising questions about the translational relevance of prominent animal and human models of addiction. These observations provide a framework for conceptualizing nicotine abstinence and withdrawal, with implications for basic, translational, and clinical science.

Behavioral and brain reactivity to uncertain stress prospectively predicts binge drinking in youth

Prior studies show that individuals with alcohol use disorder exhibit exaggerated behavioral and brain reactivity to uncertain threats (U-threat). It is posited this brain-based factor emerges early in life and contributes to the onset and escalation of alcohol problems. However, no study to date has tested this theory using a longitudinal within-subjects design. Ninety-five young adults, ages 17-19, with minimal alcohol exposure and established risk factors for alcohol use disorder participated in this multi-session study with a 1-year tracking period. Startle eyeblink potentiation and brain activation were collected at separate baseline sessions during the well-validated No-Predictable-Unpredictable (NPU) threat-of-shock task designed to probe reactivity to U-threat and predictable threat (P-threat). Participants self-reported their drinking behavior over the past 90 days at baseline and one-year later. We fit a series of multilevel hurdle models to model the binary outcome of whether binge drinking occurred and the continuous outcome of number of binge drinking episodes. Zero-inflated binary submodels revealed that greater baseline startle reactivity, bilateral anterior insula (AIC) reactivity, and dorsal anterior cingulate cortex (dACC) reactivity to U-threat were associated with increased probability of binge drinking. There were no other associations between reactivity to U- and P-threat and probability of binge drinking and number of binging episodes. These results demonstrate that exaggerated reactivity to U-threat is a brain-based individual difference factor that connotes risk for problem drinking. These findings also add to a growing literature implicating AIC and dACC dysfunction in the pathophysiology of alcohol use disorder.

A social contextual review of the effects of alcohol on emotion

Drinking and drinking problems are complex phenomena. Understanding the etiology of alcohol use disorder requires consideration of biological, psychological, and social processes. It is our view that the last of these dimensions is just beginning to receive adequate scrutiny. In this selective review, we discuss the concept of a biopsychosocial analysis of the effects of alcohol. After briefly addressing biological and psychological research on alcohol's emotional effects, we bid to make a case for the vital role that social processes play in understanding why people drink. The bulk of the paper describes research illustrating the contributions that a social psychological perspective can make to advance understanding of the rewarding effects of alcohol. Overall, studies incorporating social contexts have revealed reliable evidence that alcohol enhances emotional experience in many social environments and have identified socio-contextual variables that moderate responses to alcohol. Further, these studies have broadened the scope of constructs thought to be socially rewarding, including social bonding, relationship functioning, and humor enjoyment. Our analysis concludes by identifying research areas we believe would profit from additional research.

Alcohol's effects during uncertain and uncontrollable stressors in the laboratory

Alcohol's effects on reactivity to stressors depends on the nature of the stressor and the reactivity being assessed. Research identifying characteristics of stressors that modulate reactivity and clarifies the neurobehavioral, cognitive, and affective components of this reactivity may help prevent, reduce or treat the negative impacts of acute and chronic alcohol use with implications for other psychopathology involving maladaptive reactivity to stressors. We used a novel, multi-measure, cued electric shock stressor paradigm in a greater university community sample of adult recreational drinkers to test how alcohol (N=64), compared to No-alcohol (N=64), effects reactivity to stressors that vary in both their perceived certainty and controllability. Preregistered analyses suggested alcohol significantly dampened subjective anxiety (self-report) and defensive reactivity (startle potentiation) more during uncertain than during certain stressors regardless of controllability, suggesting that stressor uncertainty -but not uncontrollability- may be sufficient to enhance alcohol's stress reactivity dampening and thus negative reinforcement potential.

Emotional processes in binge drinking: A systematic review and perspective

Binge drinking is a widespread alcohol consumption pattern commonly engaged by youth. Here, we present the first systematic review of emotional processes in relation to binge drinking. Capitalizing on a theoretical model describing three emotional processing steps (emotional appraisal/identification, emotional response, emotional regulation) and following PRISMA guidelines, we considered all identified human studies exploring emotional abilities among binge drinkers. A literature search was conducted in PubMed, Scopus, and PsychINFO, and a standardized methodological quality assessment was performed for each study. The main findings offered by the 43 studies included are: 1) regarding emotional appraisal/identification, binge drinking is related to heightened negative emotional states, including greater severity of depressive and anxiety symptoms, and have difficulties in recognizing emotional cues expressed by others; 2) regarding emotional response, binge drinkers exhibit diminished emotional response compared with non-binge drinkers; 3) regarding emotional regulation, no experimental data currently support impaired emotion regulation in binge drinking. Variability in the identification and measurement of binge drinking habits across studies limits conclusions. Nevertheless, current findings establish the relevance of emotional processes in binge drinking and set the stage for new research perspectives to identify the nature and extent of emotional impairments in the onset and maintenance of excessive alcohol use.

Anxiety and the Neurobiology of Temporally Uncertain Threat Anticipation

When extreme, anxiety-a state of distress and arousal prototypically evoked by uncertain danger-can be debilitating. Uncertain anticipation is a shared feature of situations that elicit signs and symptoms of anxiety across psychiatric disorders, species, and assays. Despite the profound significance of anxiety for human health and wellbeing, the neurobiology of uncertain-threat anticipation remains unsettled. Leveraging a paradigm adapted from animal research and optimized for fMRI signal decomposition, we examined the neural circuits engaged during the anticipation of temporally uncertain and certain threat in 99 men and women. Results revealed that the neural systems recruited by uncertain and certain threat anticipation are anatomically colocalized in frontocortical regions, extended amygdala, and periaqueductal gray. Comparison of the threat conditions demonstrated that this circuitry can be fractionated, with frontocortical regions showing relatively stronger engagement during the anticipation of uncertain threat, and the extended amygdala showing the reverse pattern. Although there is widespread agreement that the bed nucleus of the stria terminalis and dorsal amygdala-the two major subdivisions of the extended amygdala-play a critical role in orchestrating adaptive responses to potential danger, their precise contributions to human anxiety have remained contentious. Follow-up analyses demonstrated that these regions show statistically indistinguishable responses to temporally uncertain and certain threat anticipation. These observations provide a framework for conceptualizing anxiety and fear, for understanding the functional neuroanatomy of threat anticipation in humans, and for accelerating the development of more effective intervention strategies for pathological anxiety.SIGNIFICANCE STATEMENT Anxiety-an emotion prototypically associated with the anticipation of uncertain harm-has profound significance for public health, yet the underlying neurobiology remains unclear. Leveraging a novel neuroimaging paradigm in a relatively large sample, we identify a core circuit responsive to both uncertain and certain threat anticipation, and show that this circuitry can be fractionated into subdivisions with a bias for one kind of threat or the other. The extended amygdala occupies center stage in neuropsychiatric models of anxiety, but its functional architecture has remained contentious. Here we demonstrate that its major subdivisions show statistically indistinguishable responses to temporally uncertain and certain threat. Collectively, these observations indicate the need to revise how we think about the neurobiology of anxiety and fear.

BNST and amygdala activation to threat: Effects of temporal predictability and threat mode

Recent animal and human studies highlight the uncertainty about the onset of an aversive event as a crucial factor for the involvement of the centromedial amygdala (CM) and bed nucleus of the stria terminalis (BNST) activity. However, studies investigating temporally predictable or unpredictable threat anticipation and confrontation processes are rare. Furthermore, the few existing fMRI studies analyzing temporally predictable and unpredictable threat processes used small sample sizes or limited fMRI paradigms. Therefore, we measured functional brain activity in 109 predominantly female healthy participants during a temporally predictable-unpredictable threat paradigm, which aimed to solve limited aspects of recent studies. Results showed higher BNST activity compared to the CM during the cue indicating that the upcoming confrontation is aversive relative to the cue indicating an upcoming neutral confrontation. Both the CM and BNST showed higher activity during the confrontation with unpredictable and aversive stimuli, but the reaction to aversive confrontation relative to neutral confrontation was stronger in the CM compared to the BNST. Additional modulation analyses by NPSR1 rs324981 genotype revealed higher BNST activity relative to the CM in unpredictable anticipation relative to predictable anticipation in T-carriers compared to AA carriers. Our results indicate that during the confrontation with aversive or neutral stimuli, temporal unpredictability modulates CM and BNST activity. Further, there is a differential activity concerning threat processing, as BNST is more involved when focussing on fear-related anticipation processes and CM is more involved when focussing on threat confrontation.

Stress Allostasis in Substance Use Disorders: Promise, Progress, and Emerging Priorities in Clinical Research

Clinicians and researchers alike have long believed that stressors play a pivotal etiologic role in risk, maintenance, and/or relapse of alcohol and other substance use disorders (SUDs). Numerous seminal and contemporary theories on SUD etiology posit that stressors may motivate drug use and that individuals who use drugs chronically may display altered responses to stressors. We use foundational basic stress biology research as a lens through which to evaluate critically the available evidence to support these key stress-SUD theses in humans. Additionally, we examine the field's success to date in targeting stressors and stress allostasis in treatments for SUDs. We conclude with our recommendations for how best to advance our understanding of the relationship between stressors and drug use, and we discuss clinical implications for treatment development.

Behavioral and neural sensitivity to uncertain threat in individuals with alcohol use disorder: Associations with drinking behaviors and motives

A developing theory is that individuals with alcohol use disorder (AUD) display exaggerated reactivity to threats that are uncertain (U-threat), which facilitates excessive drinking as a means of avoidance-based coping. There is a promising initial behavioral evidence supporting this theory; however, the neural bases of reactivity to U-threat in individuals with AUD have not been examined. The extent to which biomarkers of U-threat reactivity map onto drinking behaviors and coping motives for alcohol use is also unknown. The current study therefore examined group differences in behavioral and neural reactivity to U-threat in adults with and without AUD. The study also tested whether behavior and brain responses to U-threat correlate with problematic drinking and coping motivated drinking. Volunteers (n = 65) with and without a history of AUD (38 AUD, 27 controls) were included and completed a well-validated threat-of-shock task to probe responses to U-threat and predictable threat (P-threat) while startle eyeblink potentiation was collected. Individuals also completed a newly designed, analogous version of the task during functional magnetic resonance imaging (fMRI). Results indicated that individuals with AUD displayed greater startle magnitude during U-threat, but not P-threat, and greater right insula and dorsal anterior cingulate cortex (dACC) activation during both forms of threat compared with controls. Startle magnitude and insula activation during U-threat positively correlated with self-reported problem drinking and coping motives for alcohol use. Findings demonstrate that individuals with AUD display exaggerated sensitivity to U-threat at the behavioral and neural level and that these multimethod biomarkers tap into negative reinforcement processes of alcohol abuse.

Interpersonal trauma exposure and startle reactivity to uncertain threat in individuals with alcohol use disorder

BACKGROUND

Exposure to interpersonal trauma is highly prevalent within individuals with alcohol use disorder (AUD); however, the mechanisms underlying the pathway between trauma exposure and AUD are unclear. Preliminary evidence suggests that heightened reactivity to threats that are uncertain (U-threat) may characterize individuals with AUD and interpersonal trauma exposure and contribute to alcohol abuse within this subgroup of individuals; however, this hypothesis has yet to be tested.

METHOD

The aim of the study was to examine whether heightened reactivity to U-threat characterizes individuals with AUD and a history of interpersonal trauma. Specifically, the study compared defensive reactivity to U-threat (and predictable threat [P-threat]) in those with: 1) AUD and a history of interpersonal trauma (AUD + Trauma); 2) AUD and no history of interpersonal trauma (AUD-Trauma); and 3) matched controls. Participants (N = 77) completed a well-validated threat-of-shock task and startle eyeblink potentiation was collected as an index of aversive responding.

RESULTS

Results revealed a group by threat condition interaction (F[4, 142] = 3.17, p = 0.03; ηG2 = 0.08) such that individuals with AUD + Trauma exhibited greater startle reactivity to U-threat, but not P-threat, compared with individuals with AUD-Trauma and controls (who did not differ from each other). The findings were significant even when controlling for current anxiety and depression symptoms.

CONCLUSIONS

Within individuals with AUD, those with a history of interpersonal trauma exposure may be a neurobiologically unique subtype characterized by exaggerated U-threat reactivity and high levels of anticipatory anxiety. Reactivity to U-threat may be a promising alcohol use prevention and intervention target for trauma-exposed individuals.

Attention and anticipation in response to varying levels of uncertain threat: An ERP study

Individual differences in responding to uncertainty have been proposed as a key mechanism of how anxiety disorders develop and are maintained. However, most empirical work has compared responding to uncertain versus certain threat dichotomously. This is a significant limitation because uncertainty in daily life occurs along a continuum of probability, ranging from very low to high chances of negative outcomes. The current study investigated (1) how varying levels of uncertainty impact attention and anticipatory emotion, and (2) how these effects are moderated by individual differences in risk factors for anxiety disorders, particularly intolerance of uncertainty (IU) and worry. Participants (n = 65) completed a card task in which the probability of shock varied across trials. Two event-related potential components were examined: the P2, an index of attention, and the stimulus-preceding negativity (SPN), an index of anticipation. The P2 tracked the level of uncertainty and was smaller for more uncertain outcomes. Participants higher in IU exhibited greater differences in the P2 across levels of uncertainty. The SPN did not track specific levels of uncertainty but was largest for uncertain threat compared with certain threat and safety. Greater worry was associated with blunting of the SPN in anticipation of all outcomes. Thus, attention appears to be sensitive to variations in uncertainty, whereas anticipation seems sensitive to uncertainty globally. The two processes appear to be distinctly related to anxiety risk factors. These results highlight the value of examining multiple aspects of anticipatory responding to varying levels of uncertainty for understanding risk for anxiety disorders.

Cued for risk: Evidence for an incentive sensitization framework to explain the interplay between stress and anxiety, substance abuse, and reward uncertainty in disordered gambling behavior

Gambling disorder is an impairing condition confounded by psychiatric co-morbidity, particularly with substance use and anxiety disorders. Yet, our knowledge of the mechanisms that cause these disorders to coalesce remains limited. The Incentive Sensitization Theory suggests that sensitization of neural "wanting" pathways, which attribute incentive salience to rewards and their cues, is responsible for the excessive desire for drugs and cue-triggered craving. The resulting hyper-reactivity of the "wanting' system is believed to heavily influence compulsive drug use and relapse. Notably, evidence for sensitization of the mesolimbic dopamine pathway has been seen across gambling and substance use, as well as anxiety and stress-related pathology, with stress playing a major role in relapse. Together, this evidence highlights a phenomenon known as cross-sensitization, whereby sensitization to stress, drugs, or gambling behaviors enhance the sensitivity and dopaminergic response to any of those stimuli. Here, we review the literature on how cue attraction and reward uncertainty may underlie gambling pathology, and examine how this framework may advance our understanding of co-mordidity with substance-use disorders (e.g., alcohol, nicotine) and anxiety disorders. We argue that reward uncertainty, as seen in slot machines and games of chance, increases dopaminergic activity in the mesolimbic pathway and enhances the incentive value of reward cues. We propose that incentive sensitization by reward uncertainty may interact with and predispose individuals to drug abuse and stress, creating a mechanism through which co-mordidity of these disorders may emerge.

Heavy marijuana use but not deprivation is associated with increased stressor reactivity

Although stressors appear to motivate marijuana use, and marijuana use, in turn, is believed to induce stress system neuroadaptations, relatively little empirical work has explicitly tested for stress neuroadaptations associated with heavy marijuana use. We examined stressor reactivity to threat of unpredictable electric shock via startle potentiation among heavy marijuana users and a control group that reported minimal history of marijuana use. Heavy marijuana users were randomly assigned to 3 days of marijuana deprivation or no deprivation. This design allowed us to test contrasts for heavy (vs. minimal) use and deprivation (vs. no deprivation) on stressor reactivity. Heavy marijuana users (both deprived and nondeprived) displayed increased startle potentiation during threat of unpredictable electric shock relative to minimal use controls. In contrast, marijuana deprivation had no effect on startle potentiation. Startle potentiation was also increased among users who reported greater stress-coping motives for their marijuana use and users with cannabis use disorder diagnoses. To our knowledge, this is the 1st study to demonstrate increased reactivity to unpredictable stressors among heavy marijuana users. However, comparable increased unpredictable stressor reactivity among patients with alcohol and other substance use disorders has been previously documented. This relationship to heavy marijuana use is consistent with predictions from rodent addiction models regarding stress neuroadaptations following heavy, chronic drug use but could also represent an etiologically relevant premorbid risk characteristic. Finally, the clinical import of unpredictable stressor reactivity is reinforced by its relationships with stress-coping motives and cannabis use disorder status. (PsycINFO Database Record

If or when? Uncertainty's role in anxious anticipation

Uncertainty is often associated with subjective distress and a potentiated anxiety response. Occurrence uncertainty, or the inability to predict if a threat will occur, has rarely been compared experimentally with temporal uncertainty, or the inability to predict when a threat will occur. The current study aimed to (a) directly compare the anxiogenic effects of anticipating these two types of uncertain threat, as indexed by the eyeblink startle response, and (b) assess the relationship between startle response to occurrence and temporal uncertainty and individual differences in self-reported intolerance of uncertainty and anxiety. The findings indicated that anticipation during occurrence uncertainty elicited a larger startle response than anticipating a certain threat, but anticipation during temporal uncertainty was superior at potentiating startle blink overall. Additional analyses of the effects of order and habituation further highlighted temporal uncertainty's superiority in eliciting greater startle responding. This suggests that, while uncertainty is physiologically anxiety provoking, some level of certainty that the threat will occur enhances the robustness of the physiological anxiety response. However, self-reported anxiety was equivalent for temporal and occurrence uncertainty, suggesting that, while defensive responding may be more affected by temporal uncertainty, people perceive both types of uncertainty as anxiogenic. Individual differences in the intolerance of uncertainty and other anxiety measures were not related to anticipatory startle responsivity during any of the conditions.

Probing for Neuroadaptations to Unpredictable Stressors in Addiction: Translational Methods and Emerging Evidence

Stressors clearly contribute to addiction etiology and relapse in humans, but our understanding of specific mechanisms remains limited. Rodent models of addiction offer the power, flexibility, and precision necessary to delineate the causal role and specific mechanisms through which stressors influence alcohol and other drug use. This review describes a program of research using startle potentiation to unpredictable stressors that is well positioned to translate between animal models and clinical research with humans on stress neuroadaptations in addiction. This research rests on a solid foundation provided by three separate pillars of evidence from (a) rodent behavioral neuroscience on stress neuroadaptations in addiction, (b) rodent affective neuroscience on startle potentiation, and (c) human addiction and affective science with startle potentiation. Rodent stress neuroadaptation models implicate adaptations in corticotropin-releasing factor and norepinephrine circuits within the central extended amygdala following chronic alcohol and other drug use that mediate anxious behaviors and stress-induced reinstatement among drug-dependent rodents. Basic affective neuroscience indicates that these same neural mechanisms are involved in startle potentiation to unpredictable stressors in particular (vs. predictable stressors). We believe that synthesis of these evidence bases should focus us on the role of unpredictable stressors in addiction etiology and relapse. Startle potentiation in unpredictable stressor tasks is proposed to provide an attractive and flexible test bed to encourage tight translation and reverse translation between animal models and human clinical research on stress neuroadaptations. Experimental therapeutics approaches focused on unpredictable stressors hold high promise to identify, repurpose, or refine pharmacological and psychosocial interventions for addiction.

Alcohol's effects on emotionally motivated attention, defensive reactivity and subjective anxiety during uncertain threats

Developing a better understanding of how and under what circumstances alcohol affects the emotions, cognitions and neural functions that precede and contribute to dangerous behaviors during intoxication may help to reduce their occurrence. Alcohol intoxication has recently been shown to reduce defensive reactivity and anxiety more during uncertain vs certain threat. However, alcohol's effects on emotionally motivated attention to these threats are unknown. Alcohol may disrupt both affective response to and attentional processing of uncertain threats making intoxicated individuals less able to avoid dangerous and costly behaviors. To test this possibility, we examined the effects of a broad range of blood alcohol concentrations on 96 participants' sub-cortically mediated defensive reactivity (startle potentiation), retrospective subjective anxiety (self-report) and cortically assessed emotionally motivated attention (probe P3 event related potential) while they experienced visually cued uncertain and certain location electric shock threat. As predicted, alcohol decreased defensive reactivity and subjective anxiety more during uncertain vs certain threat. In a novel finding, alcohol dampened emotionally motivated attention during uncertain but not certain threat. This effect appeared independent of alcohol's effects on defensive reactivity and subjective anxiety. These results suggest that alcohol intoxication dampens processing of uncertain threats while leaving processing of certain threats intact.

Increased startle potentiation to unpredictable stressors in alcohol dependence: Possible stress neuroadaptation in humans

Stress plays a key role in addiction etiology and relapse. Rodent models posit that following repeated periods of alcohol and other drug intoxication, compensatory allostatic changes occur in the central nervous system (CNS) circuits involved in behavioral and emotional response to stressors. We examine a predicted manifestation of this neuroadaptation in recently abstinent alcohol-dependent humans. Participants completed a translational laboratory task that uses startle potentiation to unpredictable (vs. predictable) stressors implicated in the putative CNS mechanisms that mediate this neuroadaptation. Alcohol-dependent participants displayed significantly greater startle potentiation to unpredictable than predictable stressors relative to nonalcoholic controls. The size of this effect covaried with alcohol-related problems and degree of withdrawal syndrome. This supports the rodent model thesis of a sensitized stress response in abstinent alcoholics. However, this effect could also represent premorbid risk or mark more severe and/or comorbid psychopathology. Regardless, pharmacotherapy and psychological interventions may target unpredictable stressor response to reduce stress-induced relapse. (PsycINFO Database Record

Impact of alcohol use motives and internalizing symptoms on mood changes in response to drinking: An ecological momentary assessment investigation

BACKGROUND

Theory implies that individuals who use alcohol to cope with negative emotions experience the acute mood-altering effects they desire. However, no study to date has directly tested whether alcohol coping motives map onto alcohol-induced changes in mood in real-time or how co-occurring internalizing symptoms (i.e., depression and anxiety) impact the relation between coping motives and alcohol-induced changes in mood.

METHOD

The current study tested the unique and interactive effects of alcohol coping motives and internalizing symptoms on mood changes during drinking using ecological momentary assessment (EMA) in a sample of young adults (n=257). Participants completed a battery of questionnaires and a 7-day EMA assessment protocol.

RESULTS

In general, alcohol use was associated with greater positive mood and reduced negative mood while drinking. However, individuals who reported that they use alcohol to cope with anxiety, but not depression, experienced less mood benefits from alcohol relative to those without mood coping motives. In contrast, individuals with high internalizing symptoms experienced greater mood benefits while drinking relative to those with low levels of internalizing symptoms; and at high levels of anxiety, alcohol consumption was reinforcing for everyone regardless of coping motives. Only at low levels of anxiety symptoms, did coping with anxiety motives attenuate alcohol's acute reinforcing effects.

CONCLUSIONS

These results together confirm that alcohol has a robust impact on real-time mood in young adults and sheds light on the processes that may contribute to repeated alcohol use within individuals who do, and do not, use alcohol as a means of coping.

Altered subjective reward valuation among female heavy marijuana users

Maladaptive decision-making is a cardinal feature of drug use, contributing to ongoing use, and reflecting alterations in how drug users assess uncertain reward value. Accumulating evidence indicates the consequences of heavy marijuana use are worse for female versus male animals and humans, but research assessing sex differences in reward-related decision-making among marijuana users remains scarce. We examined sex differences in the subjective valuation of certain and uncertain rewards among heavy marijuana users (52; 26 male and 26 female) and controls (52; 26 male and 26 female). We offered male and female heavy marijuana users and controls monetary rewards of certain and uncertain (probabilistic) values. We measured how preferences for uncertain rewards varied by the objective value of those rewards, moderators of reward uncertainty, Marijuana Group and Sex. Men were more sensitive to changes in the objective value of uncertain rewards than women. However, this effect of Sex differed by Marijuana Group. Female heavy marijuana users were more sensitive to changes in uncertain reward value, particularly when the "stakes" were high (i.e., greater difference between potential uncertain rewards), than female controls. Female heavy marijuana users' sensitivity to changes in the value of high stakes uncertain rewards was comparable to male marijuana users and controls. In contrast, male marijuana users' sensitivity to changes in the value of high stakes uncertain rewards did not differ from male controls. These results suggest sex differences in sensitivity to high risk rewards may be one pathway contributing to severer consequences of heavy marijuana use among women. (PsycINFO Database Record

The effects of alcohol on emotion in social drinkers

Understanding why people drink alcohol and in some cases develop drinking problems has long puzzled researchers, clinicians, and patients alike. In the mid-1940s and early 1950s, experimental research began to systematically investigate alcohol's hedonic properties. Presumably, alcohol consumption would prove reinforcing as a consequence of its capacity either to relieve stress or to brighten positive emotional experiences. This article reviews experimental research through the years examining the impact of alcohol on both the relief of negative affect and the enhancement of positive affect. It covers initial accounts that emphasized direct pharmacological effects of ethanol on the central nervous system. These early studies offered surprisingly tepid support for the premise that alcohol improved emotional states. Next, studies conducted in the 1970s are considered. Informed by social learning theory and employing advances derived from experimental psychology, this research sought to better understand the complex effects of alcohol on emotion. Coverage of this work is followed by discussion of current formulations, which integrate biological and behavioral approaches with the study of cognitive, affective, and social processes. These current perspectives provide insight into the particular conditions under which alcohol can boost emotional experiences. Finally, future research directions and clinical implications are considered.

Reactivity to uncertain threat as a familial vulnerability factor for alcohol use disorder

BACKGROUND

When sober, problematic drinkers display exaggerated reactivity to threats that are uncertain (U-threat). Since this aversive affective state can be alleviated via acute alcohol intoxication, it has been posited that individuals who exhibit heightened reactivity to U-threat at baseline are motivated to use alcohol as a means of avoidance-based coping, setting the stage for excessive drinking. To date, however, no study has attempted to characterize the dispositional nature of exaggerated reactivity to U-threat and test whether it is a vulnerability factor or exclusively a disease marker of problematic alcohol use.

METHOD

The current investigation utilized a family study design to address these gaps by examining whether (1) reactivity to U-threat is associated with risk for problematic alcohol use, defined by family history of alcohol use disorder (AUD) and (2) reactivity to U-threat is correlated amongst adult biological siblings. A total of 157 families, and 458 individuals, participated in the study and two biological siblings completed a threat-of-shock task designed to probe reactivity to U-threat and predictable threat (P-threat). Startle potentiation was collected as an index of aversive responding.

RESULTS

Within biological siblings, startle potentiation to U-threat [intraclass correlation (ICC) = 0.35] and P-threat (ICC = 0.63) was significantly correlated. In addition, independent of an individuals' own AUD status, startle potentiation to U-threat, but not P-threat, was positively associated with risk for AUD (i.e. AUD family history).

CONCLUSION

This suggests that heightened reactivity to U-threat may be a familial vulnerability factor for problematic drinking and a novel prevention target for AUD.

Dispositional negativity: An integrative psychological and neurobiological perspective

Dispositional negativity-the propensity to experience and express more frequent, intense, or enduring negative affect-is a fundamental dimension of childhood temperament and adult personality. Elevated levels of dispositional negativity can have profound consequences for health, wealth, and happiness, drawing the attention of clinicians, researchers, and policymakers. Here, we highlight recent advances in our understanding of the psychological and neurobiological processes linking stable individual differences in dispositional negativity to momentary emotional states. Self-report data suggest that 3 key pathways-increased stressor reactivity, tonic increases in negative affect, and increased stressor exposure-explain most of the heightened negative affect that characterizes individuals with a more negative disposition. Of these 3 pathways, tonically elevated, indiscriminate negative affect appears to be most central to daily life and most relevant to the development of psychopathology. New behavioral and biological data provide insights into the neural systems underlying these 3 pathways and motivate the hypothesis that seemingly "tonic" increases in negative affect may actually reflect increased reactivity to stressors that are remote, uncertain, or diffuse. Research focused on humans, monkeys, and rodents suggests that this indiscriminate negative affect reflects trait-like variation in the activity and connectivity of several key brain regions, including the central extended amygdala and parts of the prefrontal cortex. Collectively, these observations provide an integrative psychobiological framework for understanding the dynamic cascade of processes that bind emotional traits to emotional states and, ultimately, to emotional disorders and other kinds of adverse outcomes. (PsycINFO Database Record

Association between problematic alcohol use and reactivity to uncertain threat in two independent samples

BACKGROUND

Recent laboratory studies have shown that acute alcohol intoxication selectively and effectively dampens aversive responding to uncertain threat. An emerging hypothesis is that individuals who exhibit heightened reactivity to uncertain threat may be especially motivated to use alcohol to dampen their distress, setting the stage for negative reinforcement processes to drive excessive alcohol use. However, no study to date has directly examined whether current problematic drinkers exhibit heightened reactivity to uncertain threat as would be expected.

METHODS

The present study was therefore designed to examine the association between current problematic alcohol use and reactivity to uncertain threat during sobriety in two, independent samples. In Study 1 (n=221) and Study 2 (n=74), adult participants completed the same well-validated threat-of-shock task which separately probes responses to temporally predictable and unpredictable threat. Startle potentiation was measured as an index of aversive responding. Problematic alcohol use was defined as number of binge episodes within the past 30days in Study 1 and total scores on a self-report measure of hazardous drinking in Study 2.

RESULTS

As hypothesized, across both studies greater levels of problematic drinking were associated with greater startle potentiation to unpredictable threat. In Study 2, hazardous drinking scores were also positively associated with startle potentiation to predictable threat.

CONCLUSIONS

The findings are notably consistent with the notion that heightened reactivity to uncertain threat is an important individual difference factor associated with the onset and/or maintenance of problematic drinking behaviors and may therefore be a novel prevention and intervention target.

Emotion regulation during threat: Parsing the time course and consequences of safety signal processing

Improved understanding of fear inhibition processes can inform the etiology and treatment of anxiety disorders. Safety signals can reduce fear to threat, but precise mechanisms remain unclear. Safety signals may acquire attentional salience and affective properties (e.g., relief) independent of the threat; alternatively, safety signals may only hold affective value in the presence of simultaneous threat. To clarify such mechanisms, an experimental paradigm assessed independent processing of threat and safety cues. Participants viewed a series of red and green words from two semantic categories. Shocks were administered following red words (cue+). No shocks followed green words (cue-). Words from one category were defined as safety signals (SS); no shocks were administered on cue+ trials. Words from the other (control) category did not provide information regarding shock administration. Threat (cue+ vs. cue-) and safety (SS+ vs. SS-) were fully crossed. Startle response and ERPs were recorded. Startle response was increased during cue+ versus cue-. Safety signals reduced startle response during cue+, but had no effect on startle response during cue-. ERP analyses (PD130 and P3) suggested that participants parsed threat and safety signal information in parallel. Motivated attention was not associated with safety signals in the absence of threat. Overall, these results confirm that fear can be reduced by safety signals. Furthermore, safety signals do not appear to hold inherent hedonic salience independent of their effect during threat. Instead, safety signals appear to enable participants to engage in effective top-down emotion regulatory processes.

Altered subjective reward valuation among drug-deprived heavy marijuana users: Aversion to uncertainty

Marijuana is the most commonly used illicit drug in the United States and its use is rising. Nonetheless, scientific efforts to clarify the risk for addiction and other harm associated with marijuana use have been lacking. Maladaptive decision-making is a cardinal feature of addiction that is likely to emerge in heavy users. In particular, distorted subjective reward valuation related to homeostatic or allostatic processes has been implicated for many drugs of abuse. Selective changes in responses to uncertainty have been observed in response to intoxication and deprivation from various drugs of abuse. To assess for these potential neuroadaptive changes in reward valuation associated with marijuana deprivation, we examined the subjective value of uncertain and certain rewards among deprived and nondeprived heavy marijuana users in a behavioral economics decision-making task. Deprived users displayed reduced valuation of uncertain rewards, particularly when these rewards were more objectively valuable. This uncertainty aversion increased with increasing quantity of marijuana use. These results suggest comparable decision-making vulnerability from marijuana use as other drugs of abuse, and highlights targets for intervention.

Withdrawal: Expanding a Key Addiction Construct

Withdrawal is an essential component of classical addiction theory; it is a vital manifestation of dependence and motivates relapse. However, the traditional conceptualization of withdrawal as a cohesive collection of symptoms that emerge during drug deprivation and decline with either the passage of time or reinstatement of drug use, may be inadequate to explain scientific findings or fit with modern theories of addiction. This article expands the current understanding of tobacco withdrawal by examining: (1) withdrawal variability; (2) underlying causes of withdrawal variability, including biological and person factors, environmental influences, and the influence of highly routinized behavioral patterns; (3) new withdrawal symptoms that allow for enhanced characterization of the withdrawal experience; and (4) withdrawal-related cognitive processes. These topics provide guidance regarding the optimal assessment of withdrawal and illustrate the potential impact modern withdrawal conceptualization and assessment could have on identifying treatment targets.

Anticipation of smoking sufficiently dampens stress reactivity in nicotine-deprived smokers

Most smokers attempting to quit will relapse, even when using evidence-based cessation treatment. This illustrates the need for better understanding of the relapse process to thereby improve cessation treatments. Although the impact of stress sensitivity on relapse is clear, little research has precisely examined stress reactivity in addicted individuals. Further, most research on relapse focuses on affect surrounding self-administration, and does not address potentially important preconsumption processes such as anticipation of use. We examined the effects of anticipation and actual smoking on stress reactivity in 34 deprived smokers withdrawn for 24 hr and 37 nondeprived smokers, with 37 nonsmoker controls. Using a cued shock stressor task, we measured stress reactivity via startle potentiation and self-reported anxiety. After completing the task once, smokers anticipated smoking a cigarette resting in front of them while they completed the task a second time. Smokers then smoked before completing the task a third and final time. Nonsmokers anticipated and drank water as a control. Anticipation of smoking significantly attenuated both startle potentiation and self-reported anxiety to shock cues for deprived smokers relative to nondeprived smokers. Smokers' stress reactivity was not reduced by smoking beyond the prior effect of anticipation. These results suggest that anticipation, rather than actual drug consumption, may drive the primary reinforcing effect of reduced stress reactivity in smoking. Future research is needed to understand this effect of anticipation on drug use and to determine whether anticipation would make an effective intervention target for addiction and other psychopathology that exhibits increased stress sensitivity.

Using the threat probability task to assess anxiety and fear during uncertain and certain threat

Fear of certain threat and anxiety about uncertain threat are distinct emotions with unique behavioral, cognitive-attentional, and neuroanatomical components. Both anxiety and fear can be studied in the laboratory by measuring the potentiation of the startle reflex. The startle reflex is a defensive reflex that is potentiated when an organism is threatened and the need for defense is high. The startle reflex is assessed via electromyography (EMG) in the orbicularis oculi muscle elicited by brief, intense, bursts of acoustic white noise (i.e., "startle probes"). Startle potentiation is calculated as the increase in startle response magnitude during presentation of sets of visual threat cues that signal delivery of mild electric shock relative to sets of matched cues that signal the absence of shock (no-threat cues). In the Threat Probability Task, fear is measured via startle potentiation to high probability (100% cue-contingent shock; certain) threat cues whereas anxiety is measured via startle potentiation to low probability (20% cue-contingent shock; uncertain) threat cues. Measurement of startle potentiation during the Threat Probability Task provides an objective and easily implemented alternative to assessment of negative affect via self-report or other methods (e.g., neuroimaging) that may be inappropriate or impractical for some researchers. Startle potentiation has been studied rigorously in both animals (e.g., rodents, non-human primates) and humans which facilitates animal-to-human translational research. Startle potentiation during certain and uncertain threat provides an objective measure of negative affective and distinct emotional states (fear, anxiety) to use in research on psychopathology, substance use/abuse and broadly in affective science. As such, it has been used extensively by clinical scientists interested in psychopathology etiology and by affective scientists interested in individual differences in emotion.

A social-attributional analysis of alcohol response

Conventional wisdom and survey data indicate that alcohol is a social lubricant and is consumed for its social effects. In contrast, the experimental literature examining alcohol's effects within a social context reveals that alcohol does not consistently enhance social-emotional experience. We identify a methodological factor that might explain inconsistent alcohol-administration findings, distinguishing between studies featuring unscripted interactions among naïve participants (k = 18) and those featuring scripted social interactions with individuals identified as study confederates (k = 18). While 89% of naïve-participant studies find positive effects of alcohol on mood (d = 0.5), only 11% of confederate studies find evidence of significant alcohol-related mood enhancement (d = -0.01). The naïve-participant versus confederate distinction remains robust after controlling for various moderators including stress manipulations, gender, group size, anxiety outcome measure, and within-group consistency of beverage assignment. Based on the findings of our review, we propose a multidimensional, social-attributional framework for understanding alcohol-related reward. Borrowing organizing principles from attribution theory, the social-attributional approach predicts that alcohol will enhance mood when negative outcomes are perceived to be unstable and/or self-relevant. Our framework proposes that alcohol's effects within a social context are largely explained by its tendency to free individuals from preoccupation with social rejection, allowing them to access social rewards. The social-attributional approach represents a novel framework for integrating distinct, well-validated concepts derived from several theories of alcohol's effects. It further presents promising lines of inquiry for future research examining the role of social factors in alcohol reward and addiction susceptibility.

Frontal midline theta reflects anxiety and cognitive control: meta-analytic evidence

Evidence from imaging and anatomical studies suggests that the midcingulate cortex (MCC) is a dynamic hub lying at the interface of affect and cognition. In particular, this neural system appears to integrate information about conflict and punishment in order to optimize behavior in the face of action-outcome uncertainty. In a series of meta-analyses, we show how recent human electrophysiological research provides compelling evidence that frontal-midline theta signals reflecting MCC activity are moderated by anxiety and predict adaptive behavioral adjustments. These findings underscore the importance of frontal theta activity to a broad spectrum of control operations. We argue that frontal-midline theta provides a neurophysiologically plausible mechanism for optimally adjusting behavior to uncertainty, a hallmark of situations that elicit anxiety and demand cognitive control. These observations compel a new perspective on the mechanisms guiding motivated learning and behavior and provide a framework for understanding the role of the MCC in temperament and psychopathology.

Not just noise: individual differences in general startle reactivity predict startle response to uncertain and certain threat

General startle reactivity reflects defensive reactivity independent of affective foreground. We examined the relationship between general startle reactivity and startle response to threat in three tasks with distinct manipulations of threat uncertainty. General startle reactivity was a stronger predictor of startle response during threat (vs. no threat) and uncertain (vs. certain threat). These results confirm that including general startle reactivity in our analyses can increase the power and/or precision to test effects of other focal experimental manipulations or grouping variables. Moreover, this suggests that individual differences in defensive reactivity moderate responding to threats of various types in our environment. As such, individual differences in general startle reactivity may index important psychological attributes related to trait affectivity, premorbid vulnerability for psychopathology, and manifest psychopathology.

How bad could it be? Alcohol dampens stress responses to threat of uncertain intensity

Stress response dampening is an important motive for alcohol use. However, stress reduction via alcohol (alcohol SRD) is observed inconsistently in the laboratory, and this has raised questions about the precise mechanisms and boundary conditions for these effects. Emerging evidence indicates that alcohol SRD may be observed selectively during uncertain but not certain threats. In a final sample of 89 participants, we measured stress response via potentiation of defensive startle reflex in response to threat of shock in blocks with certain (low and high) and uncertain shock intensity. Our alcohol-administration procedure produced blood alcohol concentrations (BACs) across a broad range (0.00%-0.12%) across participants. Increasing BACs were associated with linearly decreasing startle potentiation and self-reported anxiety. This SRD effect was greater during uncertain than certain threat. More broadly, these results suggest that distinct mechanisms are involved in response to threats of uncertain intensity and threats of certain intensity.