Return of fear: underlearning and overlearning

Optimizing exposure: Between-session mental rehearsal as an augmentation strategy

Exposure therapy is widely empirically supported as a treatment for anxiety disorders, but clinically significant response rates hover around 50%. This study explores strategies for consolidating the exposure memory as a way of improving efficacy. Between-session mental rehearsal of exposure learning was examined as a way of enhancing the effects of exposure therapy. Sixty-two spider-fearful individuals completed baseline questionnaires and a behavioral approach test with a live tarantula, followed by two sessions of in vivo exposures, and a post-assessment one-week later that repeated the baseline questionnaires and behavioral approach test. Skin conductance, subjective distress, and number of steps completed were recorded at each behavioral approach test. Participants were randomized to mental rehearsal or control (non-specific) rehearsal that was prompted on three occasions after each exposure session. Participants in both conditions improved from baseline to post-assessment, but mental rehearsal participants showed significantly greater improvement than control participants across questionnaire measurements of spider fear, subjective distress, and number of steps completed during the behavioral approach test. Findings suggest that between-session mental rehearsal is an effective supplement to exposure therapy. As such, mental rehearsal may be a promising avenue toward increasing treatment response rates across many psychiatric disorders that benefit from exposure therapy.

Enhancing Inhibitory Learning: The Utility of Variability in Exposure

Exposure therapy has strong empirical support as a treatment for anxiety and related disorders, yet not all participants see clinically meaningful reduction in symptoms, and some experience return of fear. In this review, we examine the theoretical models of exposure therapy, from early precursors to the contemporary inhibitory learning model. The inhibitory learning model is applied to examine one potential method of improving outcomes in exposure therapy: increasing variability in the progression of the exposure hierarchy. We explore mechanisms that support the use of variability in exposure, including the violation of expectancies to enhance learning. In addition, the role of intolerance of uncertainty in anxiety is examined; variable exposure therapy could target this transdiagnostic mechanism in anxiety and related disorders. Suggestions for future research are then offered.

An experimental test of the role of control in spider fear

It is well established that uncontrollable adverse experiences lead to increased distress, but the role of client control during psychological interventions such as exposure is less clear. Earlier studies reported inconsistent findings, most likely owing to variations in the way client control was manipulated, degree of exposure, the outcome variables chosen and the follow-up periods used. Importantly, studies to date had suggested to participants that approaching their fears was beneficial thereby biasing their choices and these studies had not measured change beyond the laboratory. We recruited 96 spider-fearful student participants (mean age=22; SD=5.9; Range=18-45; 86 female). The experimental design allowed full choice over their degree of exposure, and manipulated the degree of control as the extent to which their movement of a joystick influenced their virtual distance from a moving spider image. Those with high control were yoked with a low control counterpart to ensure equal amounts of exposure. Measures were elicited at baseline, post-exposure, and at follow-up. As predicted, compared to low control participants, those with high control over exposure approached closer toward a spider post-exposure and reported less spider avoidance after an average of 17days. No group differences were found in physiological or subjective distress during the task, nor in distress and dysfunction.

Are exposure-based cognitive behavioral therapies safe during pregnancy?

Anxiety disorders during pregnancy are highly prevalent and associated with serious and enduring consequences for both mother and child. Exposure-based cognitive behavioral (CBT) and behavioral therapies (BT) represent the most empirically supported psychosocial treatments for anxiety disorders in general adult samples. Pregnant women, however, generally have been excluded from this body of research. Evidence that pregnant women inhabit a unique biological context combined with untested assumptions that exposure would unduly stress or harm the fetus have likely prohibited inquiry. This paper seeks to remedy this gap by integrating findings from obstetric, psychiatric, and psychological research to inform central questions regarding exposure-based treatment of anxiety disorders during pregnancy. Based on available evidence, we consider the potential risks and benefits of CBT/BT for anxiety disorders during pregnancy relative to other currently available treatment options. From a multidisciplinary research perspective, we argue that exposure-based therapies are likely to be safe during pregnancy, particularly relative to the alternatives. However, we also highlight critical questions for future research to directly test the biopsychological impact of exposure-based therapies among pregnant women.

Dynamic hierarchies: a control system paradigm for exposure therapy

Exposure therapy is a widely used and well-evidenced treatment for a variety of avoidance behaviours. This paper offers a modest proposal for an improvement in how it is carried out (‘dynamic hierarchies’). The theoretical and practical context is set out, including some thoughts on the role of appraisals and cognitive dissonance, and some advantages of the method are suggested.

Contextual-specificity of short-delay extinction in humans: renewal of fear-potentiated startle in a virtual environment

A recent fear-potentiated startle study in rodents suggested that extinction was not context dependent when extinction was conducted after a short delay following acquisition, suggesting that extinction can lead to erasure of fear learning in some circumstances. The main objective of this study was to attempt to replicate these findings in humans by examining the context specificity of short-delay extinction in an ABA renewal procedure using virtual reality environments. A second objective was to examine whether renewal, if any, would be influenced by context conditioning. Subjects underwent differential aversive conditioning in virtual context A, which was immediately followed by extinction in virtual context B. Extinction was followed by tests of renewal in context A and B, with the order counterbalanced across subjects. Results showed that extinction was context dependent. Evidence for renewal was established using fear-potentiated startle as well as skin conductance and fear ratings. In addition, although contextual anxiety was greater in the acquisition context than in the extinction context during renewal, as assessed with startle, context conditioning did not influence the renewal effect. These data do not support the view that extinction conducted shortly after acquisition is context independent. Hence, they do not provide evidence that extinction can lead to erasure of a fear memory established via Pavlovian conditioning.

Spontaneous recovery of a conditioned taste aversion differentially alters extinction-induced changes in c-Fos protein expression in rat amygdala and neocortex

Conditioned taste aversions (CTAs) may be acquired when an animal consumes a novel taste (conditioned stimulus; CS) and then experiences the symptoms of poisoning (unconditioned stimulus; US). Animals will later avoid the taste that was previously associated with malaise. Extinction of a CTA is observed following repeated, non-reinforced exposures to the CS and represents itself as a resumption of eating/drinking the once-avoided tastant. Spontaneous recovery (SR) of a CTA (a revival of the taste avoidance) occurs when the CS is offered after a latency period in which the CS was not presented. An initial study explored the experimental parameters required to produce a reliable SR following acquisition and extinction of a robust CTA in rats. A CTA was formed through 3 pairings of 0.3% oral saccharin (SAC) and 81 mg/kg i.p. lithium chloride (LiCl) followed by extinction training resulting in 90% reacceptance of SAC. After extinction training, some of the animals were also tested for SR of the CTA upon exposure to SAC following a 15-, 30-, or 60-day latency period of water drinking. We report here that latencies of 15, 30, or 60 days produced small, but reliable, SRs of the CTA--with longer latencies producing progressively more suppression of SAC consumption. A second study investigated changes in the amygdala (AMY), gustatory neocortex (GNC), and medial prefrontal cortex (mPFC) functioning during SR of a CTA. Using immunohistochemical methods, brain c-Fos protein expression was analyzed in rats that extinguished the CTA as well as those that exhibited SR of the CTA after a 30-day latency. Our previous studies indicated that the numbers of c-Fos-labeled neurons in GNC and mPFC is low following CTA acquisition and increase dramatically as rats fully extinguished the aversion. Here we report that cortical c-Fos protein expression declines significantly following SR of the CTA. Expression of c-Fos in basolateral AMY decreased significantly from EXT to SR, but control animals with an intact CTA also decreased significantly from a short-term CTA test to a long-term CTA test. Low levels of c-Fos expression in the central nucleus of the amygdala (CE) were observed throughout EXT with little change in expression detectable following SR. These measurements reflect the dynamic nature of brain activity during acquisition and extinction of a CTA and highlight an important role for cortical neurons in the brain reorganization that occurs during SR of a CTA. The data also suggest that certain sub-nuclei of the AMY may play a relatively minor role in SR of this defensive reaction to a learned fear.

Research on posttreatment return of claustrophobic fear, arousal, and avoidance using mock diagnostic imaging

Fear sometimes returns after attenuation via exposure. Return of fear is poorly understood due to conflicting results from diverse experiments. This article reports on two experiments in which claustrophobic fear during mock diagnostic imaging was attenuated and allowed to return so the experiments could be evaluated and return of fear studied. Attentional focus versus distraction during exposure was a between-subjects independent variable. Attempts were made to predict return of fear, return of heart-rate responsivity, and behavioral avoidance using levels of fear and heart-rate during initial mock diagnostic imaging as predictor variables. One third of participants displayed return of fear, heart-rate response, or avoidance 1 week after fear reduction. Heart-rate response during initial mock imaging predicted posttreatment return-of-fear classification; level of fear during initial imaging did not. Neither initial heart rate nor initial fear predicted return of heart-rate reactivity or avoidance. The experiments are offered as models for programmatic research.

Context-specificity of relapse: effects of therapist and environmental context on return of fear

Context-specificity of fear extinction was tested among 65 participants who were fearful of spiders by manipulating the contexts used for exposure treatment and two-week follow-up assessment. Context was defined by both meaningful (presence of a particular therapist) and incidental (room location and furnishings) environmental cues. Distinct phobic stimuli were used to examine interactions of context with stimulus. Physiological, behavioral and verbal indices of fear were measured. Results provided modest support for context-specific return of fear. With one stimulus, participants assessed in a non-treatment context at follow-up exhibited greater returns in heart rate levels. In addition, three of four participants who could not touch the stimulus at follow-up had been tested in a non-treatment context. Future investigations may benefit from greater distinctions between contexts or manipulation of contextual features more directly relevant to fear. Finally, post hoc analyses identified high trait anxiety, slow treatment response, recovery of phobic cognitions and long duration/high intensity phobic encounters post-treatment as significant predictors of increased return of fear.

Toward a standard experiment for studying post-treatment return of fear

Fear sometimes returns after successful fear attenuation via in vivo exposure to fear signals. Post-treatment return of fear is of considerable interest both practically and theoretically, but factors associated with return of fear are poorly understood due to conflicting results from procedurally diverse experiments. This paper reports two very similar experiments in which fear of animal specimens was weakened then allowed to return so that factors associated with return of fear could be studied. In each experiment attentional focus versus distraction during exposure served as a between-subjects independent variable. In each case, attempts also were made to predict return of fear via several nonmanipulated variables: initial fear, initial avoidance during voluntary exposure, initial heart rate during voluntary exposure, and speed of fear reduction during repeated exposure trials. With the sample sizes used there was only suggestive evidence that return of fear was associated with distraction during exposure, and with relatively rapid fear decline during exposure. More importantly, the experiments are offered as standard, replicable models for research that will permit procedurally homogeneous investigations of variables with which return of fear is associated.

The measurement and mismeasurement of ophidiophobia in analogue research: a procedural review

The adequacy of current paper-and-pencil measures of ophidiophobia (fear of snakes) was analyzed by reviewing the subject selection procedures in 24 published articles with the restriction that the procedures involve some form of self-report. The sample characteristics and selection procedures of these studies were reviewed in detail. We conclude that the recommendations and conclusions of these studies should not be accepted due to limited generalizability. Paper-and-pencil measures are excellent initial selection devices, but cannot stand alone in selecting ophidiophobics from the general population.

Fast, slow and sudden reductions in fear

An experiment was carried out on 30 spider-fearful and 30 snake-fearful subjects in an attempt to replicate the finding of a correlation between the rapid reduction of fear and the reduced likelihood of significant fear returning after an interval (low return of fear). It was also hoped to observe and closely examine the occurrence of sudden and enduring reductions in fear. The results from the two groups of fearful subjects were reassuringly similar. The fears of both groups were significantly reduced in a relatively brief session, and small but significant returns of fear were observed after a 2 week interval, with the slow responders reporting a higher return of fear than fast responders. The time taken to reduce the fear correlated 0.36 with the return of fear. A minority of subjects did experience a subjectively important, abrupt change in their fears, these 'glass-jar' experiences were associated with faster (overall) reductions in fear, a lower return of fear, and subjective estimates of permanent and generalized reductions of the fear.

The effect of an aversive event on the return of fear

An experiment on the return-of-fear (ROF) was carried out on 40 snake- or spider-phobic subjects in order to determine whether an arousing event that occurs shortly before retest influences the magnitude of the ROF. Additionally, we attempted to produce a reinstatement of fear by introducing an unrelated aversive event (shock) after the fear had been reduced. The arousal manipulation successfully increased subjective arousal but not heartrate responsiveness. The increases in subjective arousal were not followed by increases in ROF, and the attempt to produce a reinstatement of fear did not succeed. A significant correlation between speed of fear-reduction and ROF was obtained.