Elevated costly avoidance in anxiety disorders: Patients show little downregulation of acquired avoidance in face of competing rewards for approach

The effect of typicality training on costly safety behavior generalization

BACKGROUND AND OBJECTIVES

Typicality asymmetry in generalization refers to enhanced fear generalization when trained with typical compared to atypical exemplars. Typical exemplars are highly representative of their category, whereas atypical exemplars are less representative. Individual risk factors, such as trait anxiety, attenuate this effect, due to the high level of threat ambiguity of atypical exemplars. Although recent research provided evidence for generalization of safety behavior, it is unclear whether this generalization also follows typicality asymmetry. This study examined (1) whether participants exhibited typicality asymmetry in the generalization of safety behavior and (2) whether this effect would be attenuated by individual risk factors, such as intolerance of uncertainty and trait anxiety.

METHODS

Participants were trained with either typical (Typical group, n = 53) or atypical (Atypical group, n = 55) exemplars in a fear and avoidance conditioning procedure. Participants acquired differential conditioned fear and costly safety behavior to the threat- and safety-related exemplars. In a following Generalization Test, the degree of safety behavior to novel exemplars of the same categories was tested.

RESULTS

The Atypical group showed greater differential safety behavior responses compared to the Typical group. Higher trait anxiety was associated with lower differential safety behavior generalization, driven by an increase in generalized responding to novel safety-related exemplars.

LIMITATIONS

This study used hypothetical cost instead of real cost.

CONCLUSIONS

Training with atypical exemplars led to greater safety behavior generalization. Moreover, individuals with high trait anxiety show impaired safety behavior generalization.

The generalization of threat beliefs to novel safety stimuli induced by safety behaviors

Safety behaviors are responses that can reduce or even prevent an expected threat. Moreover, empirical studies have shown that using safety behaviors to a learnt safety stimulus can induce threat beliefs to it. No research so far has examined whether threat beliefs induced this way generalize to other novel stimuli related to the safety stimulus. Using a fear and avoidance conditioning model, the current study (n=116) examined whether threat beliefs induced by safety behaviors generalize to other novel generalization stimuli (GSs). Participants first acquired safety behaviors to a threat predicting conditioned stimulus (CSthreat). Safety behaviors could then be performed in response to one safe stimulus (CSsafeShift) but not to another (CSsafe). In a following generalization test, participants showed a significant but small increase in threat expectancies to GSs related to CSsafeShift compared to GSs related to CSsafe. Interestingly, the degree of safety behaviors used to the CSsafeShift predicted the subsequent increase in generalized threat expectancies, and this link was elevated in trait anxious individuals. The findings suggest that threat beliefs induced by unnecessary safety behaviors generalize to other related stimuli. This study provides a potential explanation for the root of threat belief acquisition to a wide range of stimuli or situations.

The neurocomputational link between defensive cardiac states and approach-avoidance arbitration under threat

Avoidance, a hallmark of anxiety-related psychopathology, often comes at a cost; avoiding threat may forgo the possibility of a reward. Theories predict that optimal approach-avoidance arbitration depends on threat-induced psychophysiological states, like freezing-related bradycardia. Here we used model-based fMRI analyses to investigate whether and how bradycardia states are linked to the neurocomputational underpinnings of approach-avoidance arbitration under varying reward and threat magnitudes. We show that bradycardia states are associated with increased threat-induced avoidance and more pronounced reward-threat value comparison (i.e., a stronger tendency to approach vs. avoid when expected reward outweighs threat). An amygdala-striatal-prefrontal circuit supports approach-avoidance arbitration under threat, with specific involvement of the amygdala and dorsal anterior cingulate (dACC) in integrating reward-threat value and bradycardia states. These findings highlight the role of human freezing states in value-based decision making, relevant for optimal threat coping. They point to a specific role for amygdala/dACC in state-value integration under threat.

Unconditioned stimulus devaluation decreases the generalization of costly safety behaviors

Safety behaviors are often maladaptive in clinical anxiety as they typically persist without realistic threat and cause various impairments. In the laboratory, safety behaviors are modelled by responses to a conditioned stimulus (CS) that reduce the occurrence of an expected aversive unconditioned stimulus (US). Preliminary evidence suggests that US devaluation, a procedure that decreases US aversiveness, devalues the threat value of the CS and thus diminishes safety behaviors to the CS. This study (n = 78) aimed to extend this finding and examined whether US-devaluation can reduce the generalization of safety behaviors to various stimuli. After acquiring safety behaviors to CSs of different categories, the US predicted by one CS category was devalued. In test, participants showed a selective reduction in safety behaviors to novel stimuli of the devalued CS category, reflecting a decrease in generalization of safety behaviors. Trait anxiety was associated with persistent generalized safety behaviors to novel stimuli of the devalued category. We discuss how US devaluation may improve treatment outcome but also the challenges of clinical translation.

Temporal dynamics of costly avoidance in naturalistic fears: Evidence for sequential-sampling of fear and reward information

Excessive avoidance is characteristic for anxiety disorders, even when approach would lead to positive outcomes. The process of how such approach-avoidance conflicts are resolved is not sufficiently understood. We examined the temporal dynamics of approach-avoidance in intense fear of spiders. Highly fearful and non-fearful participants chose repeatedly between a fixed no spider/low reward and a spider/high reward option with varying fear (probability of spider presentation) and reward information (reward magnitude). By sequentially presenting fear and reward information, we distinguished whether decisions are dynamically driven by both information (sequential-sampling) or whether the impact of fear information is inhibited (cognitive control). Mouse movements were recorded to assess temporal decision dynamics (i.e., how strongly which information impacts decision preference at which timepoint). Highly fearful participants showed stronger avoidance despite lower gains (i.e., costly avoidance). Time-continuous multiple regression of their mouse movements yielded a stronger impact of fear compared to reward information. Importantly, presenting either information first (fear or reward) enhanced its impact during the early decision process. These findings support sequential sampling of fear and reward information, but not inhibitory control. Hence, pathological avoidance may be characterized by biased evidence accumulation rather than altered cognitive control.

A history of avoidance does not impact extinction learning in male rats

Pervasive avoidance is one of the central symptoms of all anxiety-related disorders. In treatment, avoidance behaviors are typically discouraged because they are assumed to maintain anxiety. Yet, it is not clear if engaging in avoidance is always detrimental. In this study, we used a platform-mediated avoidance task to investigate the influence of avoidance history on extinction learning in male rats. Our results show that having the opportunity to avoid during fear acquisition training does not significantly influence the extinction of auditory-cued fear in rats subjected to this platform-mediated avoidance procedure, which constitutes a realistic approach/avoidance conflict. This holds true irrespective of whether or not avoidance was possible during the extinction phase. This suggests that imposing a realistic cost on avoidance behavior prevents the adverse effects that avoidance has been claimed to have on extinction. However, avoidance does not appear to have clear positive effects on extinction learning nor on retention either.

Itsy bitsy spider: Fear and avoidance (generalization) in a free-exploratory virtual reality paradigm

Most experimental avoidance paradigms lack either control over the experimental situation or simplify real-life avoidance behavior to a great extent, making it difficult to generalize the results to the complex approach-avoidance situations that anxious individuals face in daily life. The current study aimed to examine the usability of our recently developed free-exploratory avoidance paradigm in Virtual Reality (VR) that allows for the assessment of subjective as well as behavioral avoidance in participants with varying levels of spider fear. In a VR escape room, participants searched for cues to decipher a code-locked door. Opening a wooden box marked with a post-it note (conditioned stimulus, CS) resulted in exposure to a virtual crawling spider (unconditioned stimulus, US). Avoidance of the original CS and other objects marked with the CS (generalization stimuli, GSs; EXPgen condition) or non-marked (CONT condition) objects was measured via questionnaires and relative manipulation times in a novel room. We expected a positive linear relationship between US aversiveness (levels of spider fear) and (generalization of) fear and avoidance behaviors. Avoidance learning and generalization was demonstrated on both a subjective and behavioral level. Higher levels of spider fear were, overall, related to more negative emotions in response to the encounter with the spider, higher US expectancies for the GSs, and more self-reported and behavioral avoidance of the original CS and the GSs. Finally, we explored relationships between trait anxiety and intolerance of uncertainty and fear and avoidance (generalization), but no robust associations were observed. In conclusion, we confirmed the expected positive linear relationship between spider fear and (generalization of) fear and avoidance behaviors. Our results suggest that our free-exploratory VR avoidance paradigm is well-suited to investigate avoidance behaviors and the generalization of avoidance.

A network perspective on real-life threat, anxiety, and avoidance

BACKGROUND

Anxiety, approach, and avoidance motivation crucially influence mental and physical health, especially when environments are stressful. The interplay between anxiety and behavioral motivation is modulated by multiple individual factors. This proof-of-concept study applies graph-theoretical network analysis to explore complex associations between self-reported trait anxiety, approach and avoidance motivation, situational anxiety, stress symptoms, perceived threat, perceived positive consequences of approach, and self-reported avoidance behavior in real-life threat situations.

METHODS

A total of 436 participants who were matched on age and gender (218 psychotherapy patients, 218 online-recruited nonpatients) completed an online survey assessing these factors in response to the COVID-19 pandemic.

RESULTS AND DISCUSSION

The resulting cross-sectional psychological network revealed a complex pattern with multiple positive (e.g., between trait anxiety, avoidance motivation, and avoidance behavior) and negative associations (e.g., between approach and avoidance motivation). The patient and online subsample networks did not differ significantly, however, descriptive differences may inform future research.

Persistence of extensively trained avoidance is not elevated in anxiety disorders in an outcome devaluation paradigm

BACKGROUND

A habitual avoidance component may enforce the persistence of maladaptive avoidance behavior in anxiety disorders. Whether habitual avoidance is acquired more strongly in anxiety disorders is unclear.

METHODS

Individuals with current social anxiety disorder, panic disorder and/or agoraphobia (n = 62) and healthy individuals (n = 62) completed a devaluation paradigm with extensive avoidance training, followed by the devaluation of the aversive outcome. In the subsequent test phase, habitual response tendencies were inferred from compatibility effects. Neutral control trials were added to assess general approach learning in the absence of previous extensive avoidance training.

RESULTS

The compatibility effects indicating habitual control did not differ between patients with anxiety disorders and healthy controls. Patients showed lower overall approach accuracy, but this effect was unrelated to the compatibility effects.

CONCLUSIONS

In this study, anxiety disorders were characterized by reduced approach but not stronger habitual avoidance. These results do not indicate a direct association between anxiety disorders and the acquisition of pervasive habitual avoidance in this devaluation paradigm.

Impaired action-safety learning and excessive relief during avoidance in patients with anxiety disorders

Anxiety-related disorders are characterized by high levels of avoidance, but experimental research into avoidance learning in patients is scarce. To fill this gap, we compared healthy controls (HC, n = 47) with patients with obsessive-compulsive disorder (OCD, n = 33), panic disorder with agoraphobia (PDA, n = 40), and post-traumatic stress disorder (PTSD, n = 66) in a computer-based avoidance learning task, in order to examine (1) differences in rates of avoidance responses, (2) differences in action-safety learning during avoidance, and (3) differences in subjective relief following successful avoidance. The task comprised aversive negative pictures (unconditional stimulus, US) that followed pictures of two colored lamps (conditional stimuli, CS+), but not a third colored lamp (safety stimulus, CS-), and could be avoided by pressing a button during one CS+ (CS+ avoidable) but not the other (CS+ unavoidable). Participants rated their US-expectancy and level of relief on a trial-by-trial basis. Compared to the HC group, patient groups displayed higher levels of avoidance to the safety stimulus, and higher levels of US-expectancy and relief following the safety and avoidable danger stimulus. We propose that patients with anxiety disorders have low confidence in the safety consequences of avoidance actions, which induces increased relief during US omissions that reinforce the avoidance action.

Understanding clinical fear and anxiety through the lens of human fear conditioning

Fear is an adaptive emotion that mobilizes defensive resources upon confrontation with danger. However, fear becomes maladaptive and can give rise to the development of clinical anxiety when it exceeds the degree of threat, generalizes broadly across stimuli and contexts, persists after the danger is gone or promotes excessive avoidance behaviour. Pavlovian fear conditioning has been the prime research instrument that has led to substantial progress in understanding the multi-faceted psychological and neurobiological mechanisms of fear in past decades. In this Perspective, we suggest that fruitful use of Pavlovian fear conditioning as a laboratory model of clinical anxiety requires moving beyond the study of fear acquisition to associated fear conditioning phenomena: fear extinction, generalization of conditioned fear and fearful avoidance. Understanding individual differences in each of these phenomena, not only in isolation but also in how they interact, will further strengthen the external validity of the fear conditioning model as a tool with which to study maladaptive fear as it manifests in clinical anxiety.

Costly avoidance of Pavlovian fear stimuli and the temporal dynamics of its decision process

Conflicts between avoiding feared stimuli versus approaching them for competing rewards are essential for functional behavior and anxious psychopathology. Yet, little is known about the underlying decision process. We examined approach-avoidance decisions and their temporal dynamics when avoiding Pavlovian fear stimuli conflicted with gaining rewards. First, a formerly neutral stimulus (CS+) was repeatedly paired with an aversive stimulus (US) to establish Pavlovian fear. Another stimulus (CS−) was never paired with the US. A control group received neutral tones instead of aversive USs. Next, in each of 324 trials, participants chose between a CS−/low reward and a CS+/high reward option. For the latter, probability of CS+ presentation (Pavlovian fear information) and reward magnitude (reward information) varied. Computer mouse movements were tracked to capture the decision dynamics. Although no more USs occurred, pronounced and persistent costly avoidance of the Pavlovian fear CS+ was found. Time-continuous multiple regression of movement trajectories revealed a stronger and faster impact of Pavlovian fear compared to reward information during decision-making. The impact of fear information, but not reward information, modestly decreased across trials. These findings suggest a persistently stronger weighting of fear compared to reward information during approach-avoidance decisions, which may facilitate the development of pathological avoidance.

Anhedonia in Anxiety Disorders

Humans, like other animals, are fundamentally motivated to pursue rewarding outcomes and avoid aversive ones. Anxiety disorders are conceptualized, defined, and treated based on heightened sensitivity to perceived aversive outcomes, including imminent threats as well as those that are uncertain yet could occur in the future. Avoidance is the central strategy used to mitigate anticipated aversive outcomes - often at the cost of sacrificing potential rewards and hindering people from obtaining desired outcomes. It is for these reasons that people are often motivated to seek treatment. In this chapter, we consider whether and how anhedonia - the loss of interest in pursuing and/or reduced responsiveness to rewarding outcomes - may serve as a barrier to recovering from clinically impairing anxiety. Increasingly recognized as a prominent symptom in many individuals with elevated anxiety, anhedonia is not explicitly considered within prevailing theoretical models or treatment approaches of anxiety. Our goal, therefore, is to review what is known about anhedonia within the anxiety disorders and then integrate this knowledge into a functional perspective to consider how anhedonia could maintain anxiety and limit treatment response. Our overarching thesis is that anhedonia disrupts the key processes that are central to supporting anxiety recovery. We end this chapter by considering how explicitly targeting anhedonia in treatment can optimize outcomes for anxiety disorders.

Avoiding a feared stimulus: Modelling costly avoidance of learnt fear in a sensory preconditioning paradigm

Avoidance of learnt fear prevents the onset of a feared stimulus and the threat that follows. In anxiety-related disorders, it turns pathological given its cost and persistence in the absence of realistic threat. The current study examined the acquisition of costly avoidance of learnt fear in healthy individuals (n = 45), via a sensory preconditioning paradigm. Two neutral preconditioning stimuli (PSs) were paired with two neutral conditioned stimuli (CSs). One CS then came to predict an aversive outcome whereas the other CS came to predict safety. In test, participants engaged in stronger avoidance to the PS associated with the fear-related CS than the PS associated with the safety-related CS. Of note, executing behavioral avoidance led to missing out a competing reward, thus rendering avoidance costly. The results also provide preliminary evidence that threat anticipation and a negative change in valence play a role in driving costly avoidance of learnt fear. Future studies should examine how avoidance of learnt fear maintains pathological anxiety.