The Effect of modality specific interference on working memory in recalling aversive auditory and visual memories.

Both auditory and visual emotional memories can be made less emotional by loading working memory (WM) during memory recall. Taxing WM during recall can be modality specific (giving an auditory [visuospatial] load during recall of an auditory [visual] memory) or cross modal (an auditory load during visual recall or vice versa). We tested whether modality specific loading taxes WM to a larger extent than cross modal loading. Ninety-six participants undertook a visual and auditory baseline Random Interval Repetition task (i.e. responding as fast as possible to a visual or auditory stimulus by pressing a button). Then, participants recalled a distressing visual and auditory memory, while performing the same visual and auditory Random Interval Repetition task. Increased reaction times (compared to baseline) were indicative of WM loading. Using Bayesian statistics, we compared five models in terms of general and modality specific taxation. There was support for the model describing the effect on WM of dual tasking in general, irrespective of modality specificity, and for the model describing the effect of modality specific loading. Both models combined gained the most support. The results suggest a general effect of dual tasking on taxing WM and a superimposed effect of taxing in matched modality.

Presence and Predictive Value of Obsessive-Compulsive Symptoms in Anxiety and Depressive Disorders.

OBJECTIVE: Obsessive-compulsive symptoms (OCS) co-occur frequently with anxiety and depressive disorders, but the nature of their relationship and their impact on severity of anxiety and depressive disorders is poorly understood. In a large sample of patients with anxiety and depressive disorders, we assessed the frequency of OCS, defined as a Young Adult Self-Report Scale-obsessive-compulsive symptoms score >7. The associations between OCS and severity of anxiety and/or depressive disorders were examined, and it was investigated whether OCS predict onset, relapse, and persistence of anxiety and depressive disorders. METHODS: Data were obtained from the third (at 2-year follow-up) and fourth wave (at 4-year follow-up) of data collection in the Netherlands Study of Anxiety and Depression cohort, including 469 healthy controls, 909 participants with a remitted disorder, and 747 participants with a current anxiety and/or depressive disorder. RESULTS: OCS were present in 23.6% of the total sample, most notably in those with current combined anxiety and depressive disorders. In patients with a current disorder, OCS were associated with severity of this disorder. Moreover, OCS predicted (1) first onset of anxiety and/or depressive disorders in healthy controls (odds ratio [OR], 5.79; 95% confidence interval [CI], 1.15 to 29.14), (2) relapse in those with remitted anxiety and/or depressive disorders (OR, 2.31; 95% CI, 1.55 to 3.46), and (3) persistence in patients with the combination of current anxiety and depressive disorders (OR, 4.42; 95% CI, 2.54 to 7.70) within the 2-year follow-up period Conclusions: OCS are closely related to both the presence and severity of anxiety and depressive disorders and affect their course trajectories. Hence, OCS might be regarded as a course specifier signaling unfavorable outcomes. This specifier may be useful in clinical care to adapt and intensify treatment in individual patients.

Intervention strength does not differentially affect memory reconsolidation of strong memories.

Recently, it has become clear that retrieval (i.e., reactivation) of consolidated memories may return these memories into a labile state before they are restored into long-term memory ('reconsolidation'). Using behavioral manipulations, reactivated memories can be disrupted via the mechanism of novel learning. In the present study, we investigated whether changing a strong memory during reconsolidation depends on the strength of novel learning. To test this, participants (N=144) in six groups acquired a relatively strong memory on Day 1 by viewing and recalling a series of pictures three times. On Day 8, these pictures were reactivated in three groups, and they were not reactivated in the other three groups. Then, participants viewed and recalled new pictures once (weak new learning) or three times (strong new learning), or they did not learn any new pictures. On Day 9, participants performed a recognition test in which their memory for Day 1 pictures was assessed. Two main results are noted. First, the groups that reactivated pictures from Day 1 and received weak or strong new learning did not differ in memory performance. Second, these two groups consistently performed similar to groups that controlled for new learning without reactivation. Because these results contradict what was expected based on the reconsolidation hypothesis, we discuss possible explanations and implications.

No Effects of D-Cycloserine Enhancement in Exposure With Response Prevention Therapy in Panic Disorder With Agoraphobia: A Double-Blind, Randomized Controlled Trial.

PURPOSE/BACKGROUND: D-cycloserine (DCS) is a partial N-methyl-D-aspartate receptor agonist that potentially augments response to exposure therapy in anxiety disorders by enhancing extinction learning. This randomized, double-blinded, placebo-controlled augmentation trial examined (1) the effectiveness of adding 125 mg of DCS to exposure therapy (before or directly after the first 6 treatment sessions) in patients with panic disorder with agoraphobia and (2) the effectiveness of DCS augmentation preceding exposure relative to DCS augmentation directly postexposure. METHODS/PROCEDURES: Fifty-seven patients were allocated to 1 of 3 medication conditions (placebo and pre-exposure and postexposure DCS) as an addition to 6 exposure sessions within a 12-session exposure and response prevention protocol. The primary outcome measure was the mean score on the "alone" subscale of the Mobility Inventory (MI). FINDINGS/RESULTS: No differences were found in treatment outcome between DCS and placebo, administered either pre-exposure or postexposure therapy, although at 3-month follow-up, the DCS postexposure group compared with DCS pre-exposure, exhibited greater symptom reduction on the MI-alone subscale. Ancillary analyses in specific subgroups (responders vs nonresponders, early vs late responders, severely vs mildly affected patients) did not reveal any between-group DCS versus placebo differences. Finally, the study did not find an effect of DCS relative to placebo to be specific for successful exposure sessions. IMPLICATIONS/CONCLUSIONS: This study does not find an effect of augmentation with DCS in patients with severe panic disorder and agoraphobia administered either pretreatment or directly posttreatment sessions. Moreover, no preferential effects are revealed in specific subgroups nor in successful exposure sessions. Yet, a small effect of DCS administration postexposure therapy cannot be ruled out, given the relatively small sample size of this study.

Updated meta-analysis of classical fear conditioning in the anxiety disorders.

The aim of the current study was twofold: (1) to systematically examine differences in fear conditioning between anxiety patients and healthy controls using meta-analytic methods, and (2) to examine the extent to which study characteristics may account for the variability in findings across studies. Forty-four studies (published between 1920 and 2013) with data on 963 anxiety disordered patients and 1,222 control subjects were obtained through PubMed and PsycINFO, as well as from a previous meta-analysis on fear conditioning (Lissek et al.). Results demonstrated robustly increased fear responses to conditioned safety cues (CS-) in anxiety patients compared to controls during acquisition. This effect may represent an impaired ability to inhibit fear in the presence of safety cues (CS-) and/or may signify an increased tendency in anxiety disordered patients to generalize fear responses to safe stimuli resembling the conditioned danger cue (CS+). In contrast, during extinction, patients show stronger fear responses to the CS+ and a trend toward increased discrimination learning (differentiation between the CS+ and CS-) compared to controls, indicating delayed and/or reduced extinction of fear in anxiety patients. Finally, none of the included study characteristics, such as the type of fear measure (subjective vs. psychophysiological index of fear), could account significantly for the variance in effect sizes across studies. Further research is needed to investigate the predictive value of fear extinction on treatment outcome, as extinction processes are thought to underlie the beneficial effects of exposure treatment in anxiety disorders.

Anger: cause or consequence of posttraumatic stress? A prospective study of Dutch soldiers.

Many studies have shown that individuals with posttraumatic stress disorder (PTSD) experience more anger over time and across situations (i.e., trait anger) than trauma-exposed individuals without PTSD. There is a lack of prospective research, however, that considers anger levels before trauma exposure. The aim of this study was to prospectively assess the relationship between trait anger and PTSD symptoms, with several known risk factors, including baseline symptoms, neuroticism, and stressor severity in the model. Participants were 249 Dutch soldiers tested approximately 2 months before and approximately 2 months and 9 months after their deployment to Afghanistan. Trait anger and PTSD symptom severity were measured at all assessments. Structural equation modeling including cross-lagged effects showed that higher trait anger before deployment predicted higher PTSD symptoms 2 months after deployment (ß = .36), with stressor severity and baseline symptoms in the model, but not with neuroticism in the model. Trait anger at 2 months postdeployment did not predict PTSD symptom severity at 9 months, and PTSD symptom severity 2 months postdeployment did not predict subsequent trait anger scores. Findings suggest that trait anger may be a pretrauma vulnerability factor for PTSD symptoms, but does not add variance beyond the effect of neuroticism.

Concurrent and prospective associations of habitual overgeneral memory and prospection with symptoms of depression, general anxiety, obsessive compulsiveness, and post-traumatic stress.

Reduced memory specificity is associated with depression, post-traumatic stress disorder (PTSD), and some other forms of psychopathology. Reduced memory specificity is also associated with reduced specificity of envisioned future events. Research in this area has mostly relied on cue-word methods that include explicit instructions to develop specific memories of future events. These methods are limited in their ability to assess how participants habitually remember the past and imagine the future when the specificity constraints inherent in the cue-word task are removed. Sentence completions tasks have been developed that can be used to assess habitual patterns of memory and prospection. Little is known about the association of habitual memory and prospection with concurrently and prospectively assessed psychopathology. In the current study 142 participants completed sentence completion tasks tapping habitual memory and prospection at baseline and completed measures tapping psychological symptoms at baseline and 1 year later. Among other things, it was found that reduced memory specificity (but not reduced future specificity) was associated with concurrent and later depression, as well as with symptom levels of PTSD tapped 1 year beyond baseline.

Blurring of emotional and non-emotional memories by taxing working memory during recall.

Memories that are recalled while working memory (WM) is taxed, e.g., by making eye movements (EM), become blurred during the recall + EM and later recall, without EM. This may help to explain the effects of Eye Movement and Desensitisation and Reprocessing (EMDR) in the treatment of post-traumatic stress disorder (PTSD) in which patients make EM during trauma recall. Earlier experimental studies on recall + EM have focused on emotional memories. WM theory suggests that recall + EM is superior to recall only but is silent about effects of memory emotionality. Based on the emotion and memory literature, we examined whether recall + EM has superior effects in blurring emotional memories relative to neutral memories. Healthy volunteers recalled negative or neutral memories, matched for vividness, while visually tracking a dot that moved horizontally ("recall + EM") or remained stationary ("recall only"). Compared to a pre-test, a post-test (without concentrating on the dot) replicated earlier findings: negative memories are rated as less vivid after "recall + EM" but not after "recall only". This was not found for neutral memories. Emotional memories are more taxing than neutral memories, which may explain the findings. Alternatively, transient arousal induced by recall of aversive memories may promote reconsolidation of the blurred memory image that is provoked by EM.

Ironic effects of compulsive perseveration.

Individuals with obsessive-compulsive disorder (OCD) exhibit perseverative behaviours, like checking, to reduce uncertainty, but perseveration paradoxically enhances uncertainty. It is unclear what mechanism might be responsible. We hypothesised that perseverative OC-like behaviour produces "semantic satiation" and interferes with the accessibility of meaning. Healthy participants repeated 20 types of OC-like checking behaviour nonperseveratively (2 times) or perseveratively (20 times). Afterwards, they decided as quickly as possible whether a picture was semantically related to the checked object. The nonperseverative condition showed spreading of activation: Judgements were faster for related than for unrelated objects and pictures. The effect was blocked in the perseverative condition, where reaction times for related and unrelated items were similar. The results suggest that the ironic effects of compulsive perseveration are due to interference with spreading of activation.

On EMDR: eye movements during retrieval reduce subjective vividness and objective memory accessibility during future recall.

In eye movement desensitization and reprocessing (EMDR), a treatment for post-traumatic stress disorder (PTSD), patients make eye movements (EM) during trauma recall. Earlier experimental studies found that EM during recall reduces memory vividness during future recalls, and this was taken as laboratory support for the underlying mechanism of EMDR. However, reduced vividness was assessed with self-reports that may be affected by demand characteristics. We tested whether recall+EM also reduces memory vividness on a behavioural reaction time (RT) task. Undergraduates (N=32) encoded two pictures, recalled them, and rated their vividness. In the EM group, one of the pictures was recalled again while making EM. In the no-EM group one of the pictures was recalled without EM. Then fragments from both the recalled and non-recalled pictures, and new fragments were presented and participants rated whether these were (or were not) seen before. Both pictures were rated again for vividness. In the EM group, self-rated vividness of the recalled+EM picture decreased, relative to the non-recalled picture. In the no-EM group there was no difference between the recalled versus non-recalled picture. The RT task showed the same pattern. Reduction of memory vividness due to recall+EM is also evident from non-self-report data.

Reducing emotional reasoning: an experimental manipulation in individuals with fear of spiders.

Emotional reasoning involves the tendency to use subjective responses to make erroneous inferences about situations (e.g., "If I feel anxious, there must be danger") and has been implicated in various anxiety disorders. The aim of this study of individuals with fear of spiders was to test whether computerised experimental training, compared to control training, would decrease emotional reasoning, reduce fear-related danger beliefs, and increase approach behaviour towards a fear-relevant stimulus. Effects were assessed shortly after the experimental manipulation and one day later. Results showed that the manipulation significantly decreased emotional reasoning in the experimental condition, not in the control condition, and resulted in lower danger estimates of a spider, which was maintained up to one day later. No differences in approach behaviour towards the spider were found. Reducing emotional reasoning may ultimately help patients with anxiety disorders attend more to objective situational information to correct erroneous danger beliefs.

The role of self-concept clarity in prolonged grief disorder.

Three studies using independent samples of bereaved individuals were conducted to examine the association of self-concept clarity (SCC) with symptoms of prolonged grief disorder (PGD), a debilitating syndrome than can develop after bereavement. Study 1 (N = 67) showed that lower SCC was associated with greater PGD severity, independent from self-concept content change. Using a retrospective design, Study 2 (N = 116) showed that a loss can coincide with a decline in SCC, the magnitude of which was associated with acute PGD severity. Study 2 also showed that the maintenance of PGD symptoms over time was associated with a smaller increase in SCC beyond the first month of bereavement and not with this acute SCC decline. Using a prospective-longitudinal design, Study 3 (N = 121) showed that the impact of lower SCC on concurrent and prospective PGD severity was mediated by lower self-esteem, depressive avoidance, and rumination. Moreover, lower initial SCC predicted PGD severity 6 months later.

Peritraumatic dissociation after loss: latent structure and associations with psychopathology.

This study investigated the factor-structure of retrospectively assessed peritraumatic dissociation in the moments surrounding the death of a loved one and concurrent and prospective associations of such peritraumatic dissociation with loss-related emotional distress. Data were available from 168 people, bereaved in the preceding year. They completed the Peritraumatic Dissociative Experiences Questionnaire with their loss as the index event, together with measures of prolonged grief disorder, depression, and posttraumatic stress disorder; 117 completed symptom measures again 1 year later. Confirmatory factor analysis comparing the fit of four competing models showed that the eight-item one-factor model found in the first study using the Peritraumatic Dissociative Experiences Questionnaire provided the best fit to the data. Peritraumatic dissociation predicted concurrent and prospective symptom levels even when controlling for neuroticism and demographic and loss-related variables.

Time-course of eye movement-related decrease in vividness and emotionality of unpleasant autobiographical memories.

The time-course of changes in vividness and emotionality of unpleasant autobiographical memories associated with making eye movements (eye movement desensitisation and reprocessing, EMDR) was investigated. Participants retrieved unpleasant autobiographical memories and rated their vividness and emotionality prior to and following 96 seconds of making eye movements (EM) or keeping eyes stationary (ES); at 2, 4, 6, and 10 seconds into the intervention; then followed by regular larger intervals throughout the 96-second intervention. Results revealed a significant drop compared to the ES group in emotionality after 74 seconds compared to a significant drop in vividness at only 2 seconds into the intervention. These results support that emotionality becomes reduced only after vividness has dropped. The results are discussed in light of working memory theory and visual imagery theory, following which the regular refreshment of the visual memory needed to maintain it in working memory is interfered with by eye movements that also tax working memory, which affects vividness first.

Proust revisited: odours as triggers of aversive memories.

According to the Proust phenomenon, olfactory memory triggers are more evocative than other-modality triggers resulting in more emotional and detailed memories. An experimental paradigm was used to investigate this in aversive memories, similar to those experienced by patients with posttraumatic stress disorder. Seventy healthy participants watched an aversive film, while simultaneously being exposed to olfactory, auditory and visual triggers, which were matched on intensity, valence, arousal and salience. During a second session one week later, participants were randomly exposed to one of the three triggers, and asked to think back about the film and to rate the resulting memory. Results revealed that odour-evoked memories of aversive events were more detailed, unpleasant and arousing than memories evoked by auditory, but not visual, triggers.

Factors associated with outcome of cognitive-behavioural therapy for complicated grief: a preliminary study.

Complicated grief (CG), also called prolonged grief disorder, is a debilitating condition that can develop following a loss. There is growing evidence that cognitive-behavioural interventions are efficacious in the treatment of CG. The present preliminary study used data from 43 patients with CG who were randomly assigned to cognitive-behavioural therapy in an earlier treatment trial to explore (a) predictors of outcome of cognitive-behavioural therapy for CG and (b) the relationship between symptom improvement and changes in loss-related negative cognitions and avoidance behaviours. Analyses showed that worse treatment outcome was associated with lower education attainment, loss of a partner/child (instead of some other relative), early treatment discontinuation, less patient motivation and more severe CG symptoms at pre-treatment. As predicted, stronger reduction in CG severity was significantly associated with stronger reductions in negative cognitions and avoidance. Implications of these findings are discussed.

A randomized controlled dismantling study of Visual Schema Displacement Therapy (VSDT) vs an abbreviated EMDR protocol vs a non-active control condition in individuals with disturbing memories.

Background: Visual Schema Displacement Therapy (VSDT) is a novel therapy for the treatment of fears and trauma-related mental health problems including PTSD. VSDT proved to be effective in reducing emotionality of aversive memories in healthy individuals in two previous randomized controlled trials and outperformed both a non-active control condition (CC) and an abbreviated version of EMDR therapy, a well-established first-line treatment for posttraumatic stress disorder. Objectives: In an effort to enhance the understanding concerning the efficacy of VSDT, and to determine its active components, a dismantling study was conducted in individuals with disturbing memories in which the effects of VSDT were tested against EMDR therapy, a non-active CC and three different VSDT-protocols, each excluding or altering a hypothesized active component. Method: Participants (N = 144) were asked to recall an emotional aversive event and were randomly assigned to one of these six interventions, each lasting 8 minutes. Emotional disturbance and vividness of participants' memories were rated before and after the intervention and at one and four-week follow-up. Results: Replicatory Bayesian analyses supported hypotheses in which VSDT was superior to the CC and the EMDR condition in reducing emotionality, both directly after the intervention and at one week follow-up. However, at four-week follow-up, VSDT proved equal to EMDR while both treatments were superior to the CC. Concerning vividness the data also showed support for hypotheses predicting VSDT being equal to EMDR and both being superior to the CC in vividness reduction. Further analyses specifying differences between the abbreviated VSDT protocols detected no differences between these conditions. Conclusion: It remains unclear how VSDT yields its positive effects. Because VSDT appears to be unique and effective in decreasing emotionality of aversive memories, replication of the results in clinical samples is needed.

Antecedentes: La terapia de desplazamiento del esquema visual (VSDT por sus siglas en inglés) es una terapia novedosa para tratar los miedos y los problemas de salud mental relacionados con el trauma, incluido el TEPT. La VSDT demostró ser eficaz para reducir la emocionalidad de los recuerdos aversivos en individuos sanos en dos ensayos previos controlados aleatorizados y superó tanto a una condición de control no activa (CC por sus siglas en inglés) como a una versión abreviada de terapia EMDR, una terapia de primera línea bien establecida para el trastorno de estrés postraumático.Objetivos: En un esfuerzo para mejorar la comprensión de la eficacia de VSDT y para determinar sus componentes activos, se realizó un estudio de desmantelamiento en individuos con recuerdos perturbadores en el que se probaron los efectos del VSDT en contraste con la terapia EMDR, una CC no activa y tres diferentes protocolos de VSDT, cada uno excluyendo o alterando un componente activo hipotético.Método: Se pidió a los participantes (N= 144) que recordaran un evento aversivo emocionalmente y fueron asignados aleatoriamente a una de las seis intervenciones, cada una con una duración de 8 minutos. La alteración emocional y la viveza de los recuerdos de los participantes fueron calificados antes y después de la intervención y en el seguimiento luego de una y cuatro semanas.Resultados: Los análisis bayesianos replicativos apoyaron la hipótesis en las que VSDT fue superior a las condiciones CC y EMDR en la reducción de la emocionalidad, tanto directamente después de la intervención y a la semana de seguimiento. Sin embargo, a las cuatro semanas de seguimiento, VSDT resultó ser igual a EMDR mientras que ambos tratamientos fueron superiores al CC. Con respecto a la viveza, los datos también mostraron apoyo hacia las hipótesis que predicen que VSDT es igual a EMDR y que ambos son superiores a CC en la reducción de la viveza. Los análisis adicionales que especifican las diferencias entre los protocolos VSDT abreviados no detectaron diferencias entre estas condiciones.Conclusiones: No está claro cómo VSDT produce sus efectos positivos. Debido a que VSDT parece ser único y efectivo en disminuir la emocionalidad de los recuerdos aversivos, se requiere la replicación de estos estos resultados en muestras clínicas.

Irritancy expectancy alters odor perception: evidence from olfactory event-related potential research.

The aim of the present research was to investigate the influences of cognition on temporal processing of olfactory information in a health-relevant context. We investigated whether expecting an odor to cause adverse health effects alters perception of that odor. An irritation-free odor (Study 1: H(2)S; Study 2: phenyl ethyl alcohol [PEA]) was presented after which participants expected to experience either adverse sensory irritation (caused by intranasal CO(2) presentation) in one condition or no adverse effects in another condition, depending on a previously presented visual cue. Olfactory event-related potentials (OERPs) were measured to assess effects of expectations on the temporal course of olfactory processing. When participants expected irritancy after perceiving the odor of H(2)S, N1 and P3 peak amplitude and N1 latency were increased and shortened, respectively, suggesting more intense and faster processing of the odor as well as effects on salience and anticipation of sensory irritation. When the odor was PEA, only the N1 amplitude was increased. These results, obtained with OERP, provide converging evidence for comparable conclusions regarding the influence of cognition on odor perception reached with functional magnetic resonance imaging. Furthermore, the results suggest that a priori hedonic valence of an odor affects how susceptible the olfactory percept is to modulation via expectations.

A prospective examination of catastrophic misinterpretations and experiential avoidance in emotional distress following loss.

This prospective study examined the role of experiential avoidance and catastrophic misinterpretations of grief reactions in emotional distress following the death of a loved one. Eighty-two bereaved individuals completed measures of experiential avoidance, catastrophic misinterpretations, and symptom of prolonged grief disorder (PGD) and depression within the first half year of bereavement, and again completed measures assessing PGD and depression severity 1 year later. The findings showed that experiential avoidance was significantly correlated with endorsement of catastrophic misinterpretations of grief reactions. In addition, both constructs were correlated with concurrent and prospective symptom levels of PGD and depression. However, the associations between experiential avoidance and symptom levels were no longer significant, when controlling for catastrophic misinterpretations of grief reactions. Moreover, catastrophic misinterpretations but not experiential avoidance predicted PGD severity at follow-up, beyond baseline levels of PGD. Both constructs did not predict later depression beyond baseline depression. Theoretical and clinical implications of these findings are discussed.

Making eye movements during imaginal exposure leads to short-lived memory effects compared to imaginal exposure alone.

BACKGROUND AND OBJECTIVES: A plethora of eye movement desensitization and reprocessing (EMDR) analogue studies has shown that, in the short term, making eye movements (EM) during brief imaginal exposure ("recall + EM") blurs memories more than just imaginal exposure ("recall only"). Yet, results of the few studies that included a follow-up test are inconsistent. We improved this paradigm's ecological validity by including an extended intervention phase and multiple assessments per phase. We hypothesized that recall + EM results in larger immediate and 24 h reductions in memory vividness, negative valence, and distress than recall alone. We explored the persistence of the effects, as well as the predictive value of memory characteristics and individual differences. METHODS: Students (N = 100) selected a negative autobiographical memory and were randomized to recall + EM or recall alone; both interventions lasted 32 intervals of 24s. During the interventions they rated the memory after every four intervals. RESULTS: After 4 × 24s intervention, recall + EM resulted in memory deflation, while recall only caused memory inflation. After the full intervention (i.e., 32 × 24s), both conditions resulted in immediate and 24 h reductions on all outcome measures. Crucially, memory effects in the recall + EM condition partially relapsed 24 h later, while the effects in the recall only condition persisted. Change patterns were hardly explained by predictive variables. LIMITATIONS: We used a non-clinical sample; replication in clinical samples is warranted. CONCLUSION: Making EM during imaginal exposure leads to short-lived effects compared to imaginal exposure alone. However, EM may offer a response aid for those who avoid imaginal exposure.