Mechanisms of Action in Exposure Therapy

Are the Unified Protocols for Transdiagnostic Treatment of Emotional Disorders in Children and Adolescents as Effective for OCD as for Anxiety and Depression?

Background: Obsessive-compulsive disorder (OCD) in youth commonly co-occurs with other affective disorders (e.g., anxiety, depression). Exposure and response prevention (ERP) is the front-line treatment for OCD but may require significant adaptation to treat co-occurring symptoms or complex comorbidity patterns. Preliminary evidence suggests that the Unified Protocols for Transdiagnostic Treatment of Emotional Disorders in Children and Adolescents (UP-C/A) are effective in reducing OCD symptoms. Still, it is not yet known if the UP-C/A are comparably effective to treat OCD as they are for anxiety and depression, the disorders for which there is the most robust empirical support. Methods: This study compared trajectories of OCD, anxiety, and depression symptom change among 388 youth who received UP-C/A treatment (M = 15 sessions) at a university-based research clinic. We also examined whether youth with (n = 60) and without (n = 328) an OCD diagnosis demonstrated comparable improvements in anxiety, depression, and transdiagnostic treatment targets (i.e., anxiety sensitivity, cognitive flexibility, and distress tolerance). Results: OCD symptoms improved at a slower rate than anxiety and depression symptoms during the first half of UP-C/A treatment but at a comparable rate to anxiety and depression symptoms during the second half of treatment. Youth with and without OCD exhibited comparable improvements in anxiety, depression, anxiety sensitivity, cognitive flexibility, and distress tolerance across the treatment course. Conclusions: Findings support the efficacy of UP-C/A treatment for co-occurring OCD and affective disorders but suggest that initiating exposure earlier in the treatment course may confer additional benefits.

VIRTUS: virtual reality exposure training for adolescents with social anxiety - a randomized controlled trial

While virtual reality exposure (VRE) has shown effectiveness in treating social anxiety in adults, research on its efficacy for adolescents remains limited. Given that adolescence is a critical period for early intervention, this study aims to address this gap by evaluating the efficacy and acceptability of VRE compared to in vivo exposure (IVE) in a non-referred sample of socially anxious adolescents. Additionally, we seek to identify mechanisms of change-such as expectancy violation, habituation, and self-efficacy-as well as predictors of treatment response, including clinical, personality, and VR-related factors. Using a randomized controlled trial (RCT), 120 adolescents (ages 12-16) with subclinical to moderate social anxiety will be assigned to one of three conditions: VRE, IVE, or a waitlist control (WL). Participants in the active conditions will undergo a seven-session exposure-based intervention (either in VR or in vivo). Primary (SPAI-18, LSAS-avoidance) and secondary (SPWSS) measures of social anxiety, along with general well-being indicators (e.g., resilience, depression, psychosocial functioning), will be assessed at baseline, post-treatment, and 3- and 6-month follow-ups. A series of linear mixed model (LMM) analyses will be used to examine and compare the effects of the interventions. We hypothesize that both VRE and IVE will significantly reduce social anxiety symptoms compared to WL at post-assessment, with comparable long-term efficacy between the two exposure methods. Additionally, thematic analyses will be conducted to explore participants' experiences and acceptance of VRE and IVE through qualitative interviews. The findings of this study aim to advance digital mental health research by evaluating the potential of VRE as an early intervention and identifying mechanisms and predictors to inform personalized treatments for socially anxious youth.Trial registrationClinicaltrials.gov: NCT06379633, registered on April, 23, 2024.

Cholinergic signaling to CA1 astrocytes controls fear extinction

Fear extinction is an evolutionarily conserved biological process that allows an organism to better re-adapt; its deficits can lead to psychiatric disorders. Fear extinction is considered to rely mostly on neuronal function. However, whether and how astrocytes contribute to fear extinction is largely unknown. Here, we show that hippocampal CA1 astrocytes exhibit de novo Ca2+ dynamics during fear extinction. Inhibition of these astrocytic Ca2+ dynamics impairs, while their activation facilitates, fear extinction. In this regulation of fear extinction, the posterior basal forebrain (pBF) cholinergic input to hippocampus drives CA1 astrocytic Ca2+ dynamics through the activation of α4 and α7 subunits of nicotinic acetylcholine receptors. Clinically used acetylcholinesterase inhibitor donepezil increases CA1 astrocytic Ca2+ dynamics and facilitates fear extinction. Thus, our findings demonstrate a previously unrecognized and crucial pathway from pBF cholinergic neurons to CA1 astrocytes that governs natural fear extinction. This neuron-glia signaling pathway may constitute a promising target for treatment of fear- and anxiety-related disorders.

Fear and safety learning in anxiety- and stress-related disorders: An updated meta-analysis

Fear learning processes are believed to play a crucial role in the development and maintenance of anxiety and stress-related disorders. To integrate results across different studies, we conducted a systematic meta-analysis following PRISMA guidelines to examine differences in fear conditioning during fear acquisition, extinction, and extinction recall between individuals with anxiety-related or stress-related disorders and healthy participants. This analysis updates the work of Duits et al. (2015) while also refining distinctions between physiological and behavioral outcomes and examining extinction recall. Our meta-analysis encompasses 77 studies published from 1986 to 2022, involving 2052 patients with anxiety disorders, obsessive-compulsive disorder, or post-traumatic stress disorder, and 3258 healthy controls. The results indicate significant differences in fear acquisition, extinction, and recall between the two groups. Specifically, during acquisition patients exhibited heightened physiological and behavioral responses to the CS- and reported increased affect ratings for the CS+ . During extinction and extinction recall, patients continue to show heightened threat expectancy and negative affect ratings towards the CS- and increased affect ratings towards the CS+ . No differences were found in CS+ /CS- differentiation between groups. These findings imply that individuals with anxiety and stress-related disorders may exhibit amplified responses to safety cues and stronger reactions to threat cues during fear conditioning, lasting through extinction and extinction recall. These changes may lead to increased sensitivity in detecting fear and slower extinction process, resulting in more enduring anxiety responses. We discuss these results in the context of existing literature on fear and safety learning and consider potential underlying mechanisms.

Supporting parents to reduce children's anxiety: A meta-analysis of interventions and their theoretical components

Parent-focused interventions hold promise for reducing child anxiety, but their content varies greatly, and little is known on the intervention content. We estimated the effects of parent-focused interventions on child anxiety and the most effective combinations of theoretical components. We searched PsycINFO, Medline, and Web of Science in October 2022 for randomized trials on parent-focused interventions to reduce children's anxiety. We used robust variance estimation to estimate main effects and differential effects by individual theoretical components, and network meta-analysis to estimate the effects of clusters of components (preregistration: PROSPERO CRD42022362983). We identified 26 studies (k = 157, N = 4098). Parent-focused interventions had a significant medium effect on children's anxiety (d = -0.59; 95% CI [-0.92, -0.26]). Interventions used seven theoretically distinct components. No significant differential effects were found, but all clusters of components that produced significant effects contained a behavioral component. Adding cognitive and emotional components to behavioral components seemed beneficial. This meta-analysis highlights the potential of parent-focused interventions for children's anxiety, and of behavioral components in particular, but is limited by the very low certainty of evidence. More high-quality research is needed to understand the exact potential of parent-focused interventions on children's anxiety, and their most effective components.

Within-session habituation and salivary cortisol during exposure treatment in obsessive-compulsive disorder - A link and an influence of DHEA?

Background

Glucocorticoids increase fear extinction in preclinical and human studies. Endogenous cortisol might influence who will benefit from exposure therapy in anxiety-spectrum disorders.

Methods

To investigate the impact of cortisol levels on within-session habituation of distress - a measure of success of exposure therapy - in obsessive-compulsive disorder (OCD) fifty-one OCD patients were studied during their stressful first cognitive-behavioral exposure therapy session with response prevention. Subjective units of distress, salivary cortisol, and salivary dehydroepiandrosterone (DHEA) were measured repeatedly before and during this afternoon session.

Results

No significant association of within-session habituation of distress and cortisol level during exposure was found. Calculating with the cortisol/DHEA ratio, similar results emerged.

Conclusion

Studies using endogenous diurnal fluctuation of cortisol and studies with administration of exogenous cortisol are needed to test whether glucocorticoids can augment exposure session outcome.

Targeting fear memories: Examining pharmacological disruption in a generalized fear framework

Labilization-reconsolidation, which relies on retrieval, has been considered an opportunity to attenuate the negative aspects of traumatic memories. A therapeutic strategy based on reconsolidation blockade is deemed more effective than current therapies relying on memory extinction. Nevertheless, extremely stressful memories frequently prove resistant to this process. Here, after inducing robust fear memory in mice through strong fear conditioning, we examined the possibility of rendering it susceptible to pharmacological modulation based on the degree of generalized fear (GF). To achieve this, we established an ordered gradient of GF, determined by the perceptual similarity between the associated context (CA) and non-associated contexts (CB, CC, CD, and CE) to the aversive event. We observed that as the exposure context became less similar to CA, the defensive pattern shifted from passive to active behaviors in both male and female mice. Subsequently, in conditioned animals, we administered propranolol after exposure to the different contexts (CA, CB, CC, CD or CE). In males, propranolol treatment resulted in reduced freezing time and enhanced risk assessment behaviors when administered following exposure to CA or CB, but not after CC, CD, or CE, compared to the control group. In females, a similar change in behavioral pattern was observed with propranolol administered after exposure to CC, but not after the other contexts. These results highlight the possibility of indirectly manipulating a robust contextual fear memory by controlling the level of generalization during recall. Additionally, it was demonstrated that the effect of propranolol on reconsolidation would not lead to a reduction in fear memory per se, but rather to its reorganization resulting in greater behavioral flexibility (from passive to active behaviors). Finally, from a clinical viewpoint, this would be of considerable relevance since following this strategy could make the treatment of psychiatric disorders associated with traumatic memory formation more effective and less stressful.

Imagery rescripting and extinction: Effects on US expectancy, US revaluation, and the generalization of fear reduction

Exposure therapy consists of exposing patients to their fears and thereby diminishing their harm expectancies (i.e., extinction or expectancy learning). Although effective for many anxiety patients, its long-term success depends on the generalization of these harm expectancies to other stimuli. However, research shows that this generalization of extinction is limited. Besides decreasing harm expectancies, fear reduction may also be achieved by changing the meaning of an aversive memory representation (US revaluation). Imagery rescripting (ImRs) may be more successful in generalizing fear reduction because it allegedly works through US revaluation. The current experiment aimed to test working mechanisms for ImRs and extinction (revaluation and expectancy learning, respectively), and to examine generalization of fear reduction. In a fear conditioning paradigm, 113 healthy participants watched an aversive film clip that was used as the US. The manipulation consisted of imagining a script with a positive ending to the film clip (ImRs-only), extinction (extinction-only), or both (ImRs + extinction). Results showed enhanced US revaluation in ImRs + extinction. US expectancy decreased more strongly in the extinction conditions. Generalization of fear reduction was found in all conditions. Our results suggest different working mechanisms for ImRs and exposure. Future research should replicate this in (sub)clinical samples.

A network analysis of mechanisms of change during exposures over the course of intensive OCD treatment

Exposure and response prevention (ERP) is an evidence-based treatment for obsessive-compulsive disorder (OCD). Theories for how it works vary in their emphasis on active mechanisms of change. The current study aimed to clarify mechanisms of change in ERP for OCD using network analysis, comparing ERP networks at the start and end of intensive treatment (partial hospital and residential). In our sample of 182 patients, the most central node in both networks was engagement with exposure, which was consistently related to greater understanding of ERP rationale, higher willingness, and less ritualization, accounting for all other variables in the network. There were no significant differences in networks between the start and end of treatment. These results suggest that nonspecific parameters like facilitating engagement in exposures without ritualizing and providing a clear rationale to clients may be key to effective treatment. As such, it may be useful for clinicians to spend adequate time underscoring the need to eliminate rituals to fully engage in exposure tasks and explaining the rationale for ERP prior to doing exposures, regardless of theoretical orientation. Nonetheless, findings represent group-level statistics and more fine-grained idiographic analyses may reveal individual-level differences with respect to central mechanisms of change. Other limitations include demographic homogeneity of our sample.

Towards a self-applied, mobile-based geolocated exposure therapy software for anxiety disorders: SyMptOMS-ET app

Objective

While exposure therapy (ET) has the potential to help people tolerate intense situation-specific emotions and change avoidance behaviours, no smartphone solution exists to guide the process of in-vivo ET. A geolocation-based smartphone software component was designed and developed to instrumentalize patient guidance in in-vivo ET and its psychological validity was assessed by a group of independent psychology experts.

Methods

A team of computer scientists and psychologists developed the ET Component for in-vivo ET using geolocation-based technology, following the process-centred design methodology. The ET Component was integrated into the SyMptOMS-ET Android application, which was developed following the co-design methodology. Next, nine independent psychology experts tested and evaluated the ET Component and the SyMptOMS-ET app in the field, following the think-aloud methodology. Participants also completed the Mobile Application Rating Scale (MARS) instrument to quantitatively evaluate the solutions.

Results

We present the SyMptOMS-ET app's main features and the ET Component exposure workflow. Next, we discuss the feedback obtained and the results of the MARS instrument. Participants who tested the app were satisfied with the ET Component during exposure scenarios (score of μ 4.32 out of 5 [ σ 0.28] on MARS quality aspects), agreed on the soundness of the theoretical foundations of the solutions developed (score of μ 4.57 [ σ 0.48] on MARS treatment support aspects), and provided minor think-a-loud comments to improve them.

Conclusions

The results of the expert evaluation demonstrate the psychological validity of the ET Component and the SyMptOMS-ET app. However, further studies are needed to discern the acceptability and efficacy of the mHealth tool in the target population.

Morphologic alterations of the fear circuitry: the role of sex hormones and oral contraceptives

Background

Endogenous sex hormones and oral contraceptives (OCs) have been shown to influence key regions implicated in fear processing. While OC use has been found to impact brain morphology, methodological challenges remain to be addressed, such as avoiding selection bias between OC users and non-users, as well as examining potential lasting effects of OC intake.

Objective

We investigated the current and lasting effects of OC use, as well as the interplay between the current hormonal milieu and history of hormonal contraception use on structural correlates of the fear circuitry. We also examined the role of endogenous and exogenous sex hormones within this network.

Methods

We recruited healthy adults aged 23-35 who identified as women currently using (n = 62) or having used (n = 37) solely combined OCs, women who never used any hormonal contraceptives (n = 40), or men (n = 41). Salivary endogenous sex hormones and current users' salivary ethinyl estradiol (EE) were assessed using liquid chromatography - tandem mass spectrometry. Using structural magnetic resonance imaging, we extracted surface-based gray matter volumes (GMVs) and cortical thickness (CT) for regions of interest of the fear circuitry. Exploratory whole-brain analyses were conducted with surface-based and voxel-based morphometry methods.

Results

Compared to men, all three groups of women exhibited a larger GMV of the dorsal anterior cingulate cortex, while only current users showed a thinner ventromedial prefrontal cortex. Irrespective of the menstrual cycle phase, never users exhibited a thicker right anterior insular cortex than past users. While associations with endogenous sex hormones remain unclear, we showed that EE dosage in current users had a greater influence on brain anatomy compared to salivary EE levels and progestin androgenicity, with lower doses being associated with smaller cortical GMVs.

Discussion

Our results highlight a sex difference for the dorsal anterior cingulate cortex GMV (a fear-promoting region), as well as a reduced CT of the ventromedial prefrontal cortex (a fear-inhibiting region) specific to current OC use. Precisely, this finding was driven by lower EE doses. These findings may represent structural vulnerabilities to anxiety and stress-related disorders. We showed little evidence of durable anatomical effects, suggesting that OC intake can (reversibly) affect fear-related brain morphology.

Changes in trauma-related cognitions predict subsequent symptom improvement during prolonged exposure in patients with childhood abuse-related PTSD

Change in negative posttraumatic cognitions is a proposed mechanism through which Prolonged Exposure (PE) leads to symptom reduction of posttraumatic stress disorder (PTSD). A strong case for posttraumatic cognitions as a change mechanism in PTSD treatment can be made by establishing temporal precedence of change in cognitions. The current study examines the temporal relationship between change in posttraumatic cognitions and PTSD symptoms during PE, using the Posttraumatic Cognitions Inventory. Patients with DSM-5 defined PTSD following childhood abuse (N = 83) received a maximum of 14-16 sessions of PE. Clinician-rated PTSD symptom severity and posttraumatic cognitions were assessed at baseline, week 4, 8, and 16 (post-treatment). Using time-lagged mixed effect regression models, we found that posttraumatic cognitions predicted subsequent PTSD symptom improvement. Notably, when using the items of an abbreviated version of the PTCI (PTCI-9), we found a mutual relationship between posttraumatic cognitions and PTSD symptom improvement. Crucially, the effect of change in cognitions on PTSD symptom change was greater than the reverse effect. The current findings corroborate change in posttraumatic cognitions as a change process during PE, but cognitions and symptoms cannot be completely separated. The PTCI-9 is a short instrument that appears suitable to track cognitive change over time.