A high-throughput clinical assay for testing drug facilitation of exposure therapy

Social avoidance and testosterone enhanced exposure efficacy in women with social anxiety disorder: A pilot investigation

Social avoidance has been associated with more persistent social anxiety disorder (SAD) symptoms and low testosterone levels in individuals with SAD. We tested whether pre-treatment avoidance tendencies moderate the efficacy of testosterone-augmented exposure therapy. Fifty-five females with SAD received two exposure sessions during which fear levels were assessed. Session 1 was augmented with testosterone (0.50 mg) or placebo. Avoidance tendencies and symptom severity were assessed pre- and post-exposure. Participants showed stronger avoidance for social versus non-social stimuli and this tendency remained stable over time. Stronger pretreatment avoidance tendencies were associated with larger fear reduction in the testosterone but not the placebo condition. This effect did not transfer to the second non-enhanced session or symptom severity. The findings support the hypothesis that individuals suffering from SAD with relatively stronger pretreatment avoidance tendencies benefit more from testosterone-augmentation, pointing to a potential behavioral marker for testosterone enhancement of exposure therapy.

A transdiagnostic meta-analysis of acute augmentations to psychological therapy

At least half of all patients with mental health disorders do not respond adequately to psychological therapy. Acutely enhancing particular biological or psychological processes during psychological therapy may improve treatment outcomes. However, previous studies are confined to specific augmentation approaches, typically assessed within single diagnostic categories. Our objective was to assess to what degree acute augmentations of psychological therapy reduce psychiatric symptoms and estimate effect sizes of augmentation types (for example, brain stimulation or psychedelics). We searched Medline, PsycINFO and Embase for controlled studies published between database inception and 25 May 2022. We conducted a preregistered random-effects meta-analysis (PROSPERO CRD42021236403). We identified 108 studies (N = 5,889). Acute augmentation significantly reduced the severity of mental health problems (Hedges' g = -0.27, 95% CI: [-0.36, -0.18]; P < 0.0001), particularly for the transdiagnostic dimensions 'Fear' and 'Distress'. This result survived a trim-and-fill analysis to account for publication bias. Subgroup analyses revealed that pharmacological, psychological and somatic augmentations were effective, but to varying degrees. Acute augmentation approaches are a promising route to improve outcomes from psychological therapy.

The enhancing effects of testosterone in exposure treatment for social anxiety disorder: a randomized proof-of-concept trial

Individuals with a social anxiety disorder (SAD) show hypofunctioning of the hypothalamus-pituitary-gonadal (HPG) axis, which is linked to social fear and avoidance behavior. As testosterone administration has been shown to facilitate social-approach behavior in this population, it may enhance the effectiveness of exposure treatment. In this proof-of-concept study, we performed a randomized clinical assay in which 55 women diagnosed with SAD received two exposure therapy sessions. Session 1 was supplemented with either testosterone (0.50 mg) or placebo. Next, transfer effects of testosterone augmentation on within-session subjective fear responses and SAD symptom severity were assessed during a second, unenhanced exposure session (session 2) and at a 1-month follow-up, respectively. The participants having received testosterone showed a more reactive fear pattern, with higher peaks and steeper reductions in fear levels in session 2. Post-hoc exploration of moderating effects of endogenous testosterone levels, revealed that this pattern was specific for women with high basal testosterone, both in the augmented and in the transfer session. In contrast, the participants with low endogenous testosterone showed reduced peak fear levels throughout session 1, again with transfer to the unenhanced session. Testosterone did not significantly affect self-reported anxiety. The effects of testosterone supplementation on fear levels show transfer to non-enhanced exposure, with effects being modulated by endogenous testosterone. These first preliminary results indicate that testosterone may act on important fear mechanisms during exposure, providing the empirical groundwork for further exploration of multi-session testosterone-enhanced exposure treatment for SAD.

Endogenous testosterone levels are predictive of symptom reduction with exposure therapy in social anxiety disorder

The Hypothalamus-Pituitary-Gonadal (HPG)-axis, and testosterone in particular, play an important role in social motivational behavior. Socially avoidant behavior, characteristic of social anxiety disorder (SAD), has been linked to low endogenous testosterone levels, and can be alleviated by testosterone administration in SAD. Although these beneficial effects of testosterone may translate to exposure therapy, it remains unknown whether testosterone increases prior to exposure improve therapy outcomes. In this proof-of-principle study, we tested whether pre-exposure (reactive and baseline) endogenous testosterone levels were predictive of exposure outcome in SAD. Seventy-three participants (52 females) with a principal SAD diagnosis performed four speech exposures: three during one standardized exposure therapy session and one at post-assessment one week later. Subjective fear levels were assessed before and after each speech exposure and social anxiety symptoms were assessed at pre- and post-treatment. Pre-treatment testosterone levels were assessed before (baseline) and in response to a pre-exposure instruction session (reactive). Pre-treatment testosterone levels were not related to fear levels during exposure therapy, but predicted pre- to post-treatment reductions in social anxiety symptom severity. Specifically, low baseline and high reactive pre-treatment testosterone levels were associated with larger reductions in social anxiety symptom severity. These findings support the role of HPG-axis in social fear reduction. Specifically, our finding that high reactive testosterone as well as low baseline testosterone predicted exposure outcome in SAD, suggests that good reactivity of the HPG-axis is a promising marker for the symptom-reducing effects of exposure therapy.

Neurocognitive processes in d-cycloserine augmented single-session exposure therapy for anxiety: A randomized placebo-controlled trial

Drugs targeting N-methyl-d-aspartate (NMDA) receptors and the ability to learn new associations have been proposed as adjunct treatments to boost the success of exposure therapy for anxiety disorders. However, the effects of the NMDA partial agonist d-cycloserine on psychological treatment have been mixed. We investigated potential neurocognitive mechanisms underlying the clinical effects of d-cycloserine-augmented exposure, to inform the optimal combination of this and similar agents with psychological treatment. Panic disorder patients were randomised to single-dose d-cycloserine (250 mg; N = 17) or matching placebo (N = 16) 2hrs before one session of exposure therapy. Neurocognitive markers were assessed one day after treatment, including reaction-time based threat bias for fearful faces (primary outcome) and amygdala response to threat (secondary outcome). Clinical symptom severity was measured the day before and after treatment, and at 1- and 6-months follow-up (secondary outcome). d-cycloserine was associated with greater clinical recovery at 1-month follow-up than placebo (d-cyloserine 71% vs placebo 25%), with the placebo group matching the clinical gains of the d-cycloserine group during 6-months follow-up (d-cycloserine 71% vs placebo 44%). One day after treatment, threat bias for fearful faces and amygdala threat response was lower in the drug compared to placebo group. Lower amygdala magnitude predicted greater clinical improvement during follow-up across groups. While this experimental study is of a preliminary nature due to the limited sample size, these findings highlight a neurocognitive potential mechanism by which d-cycloserine may exert its augmentative effects on psychological treatment and bring forward a marker that may help understand and facilitate development of combination treatments for anxiety. (d-cycloserine Augmented CBT for Panic Disorder; clinicaltrials.gov; NCT01680107).

The Glutamate and the Immune Systems: New Targets for the Pharmacological Treatment of OCD

BACKGROUND

In the last decades the pharmacological treatment of obsessivecompulsive disorder (OCD) has been significantly promoted by the effectiveness of selective serotonin (5-HT) reuptake inhibitors (SSRIs) and the subsequent development of the 5-HT hypothesis of OCD. However, since a large majority of patients (between 40% and 60 %) do not respond to SSRIs or strategies based on the modulation of the 5-HT system, it is now essential to search for other possible therapeutic targets.

AIMS

The aim of this paper was to review current literature through a PubMed and Google Scholar search of novel hypotheses and related compounds for the treatment of OCD, with a special focus on the glutammate and the immune systems.

DISCUSSION

The literature indicates that glutamate, the main excitatory neurotransmitter, might play an important role in the pathophysiology of OCD. In addition, a series of clinical studies also supports the potential efficacy of drugs modulating the glutamate system. The role of the immune system alterations in OCD in both children and adults needs to be more deeply elucidated. In children, a subtype of OCD has been widely described resulting from infections driven by group A streptococcus β-hemolitic and belonging to the so-called "pediatric autoimmune neuropsychiatric disorders associated with streptococcus" (PANDAS). In adults, available findings are meager and controversial, although interesting.

CONCLUSION

The glutamate and the immune systems represent two intriguing topics of research that hold promise for the development of open novel treatment strategies in OCD.

Learn to forget: Does post-exposure administration of d-cycloserine enhance fear extinction in agoraphobia?

The use of d-cycloserine (DCS) to augment exposure based therapy for anxiety disorders has shown mixed, although overall positive effects. Aim of the present study was to examine post-exposure administration of DCS in patients with agoraphobia with or without panic disorder. 73 patients with agoraphobia (with or without panic disorder) were treated with 12 sessions of cognitive behavioral therapy (CBT) including 3 exposures. Following successful exposure patients were given double blind either placebo or 50 mg of DCS. Primary outcome criterion was change in the Panic and Agoraphobia Scale (PAS) between CBT session t1, t4 (+∼2 months), t10 (+∼3 months) und t11 (+∼4 months). During the course of CBT the patients' symptomatology decreased significantly as measured by primary and secondary outcome criteria, however, without an additional benefit for DCS treated patients. Exploratory sub-group analyses for severely ill patients and patients with high anxiety and strong habituation during exposure showed that DCS administration was associated with increased improvement during the 1-month follow-up period (t10 - t11) with medium to large effect sizes (range in effect size η²_p from .06 to .25). Our study results are consistent with recent research on DCS, indicating a beneficial augmentative effect for sub-groups of anxiety patients. The lack of an overall DCS effect for the whole patient sample might be explained by a dual mechanism in fear conditioning and extinction with different cognitive processes being involved during exposure depending on the degree of anxiety experienced by the patient.

Effects of d-cycloserine on individual differences in relapse of fear

The major weakness of psychological and pharmacological interventions for anxiety disorders is that the fear often returns. We examined whether DCS, which has attracted considerable attention as a potential pharmacological adjunct to therapy, reduces relapse, and whether individual differences in the rate of extinction modulates its effectiveness in reducing relapse. Experimentally-naïve adult male rats received pairings of a white noise CS with a shock US, extinction to a criterion immediately followed by an injection of DCS or Saline, and then were tested for relapse of fear (renewal, spontaneous recovery, or reinstatement; in four separate experiments). The number of blocks to reach criteria in extinction was used to classify animals as "Fast" or "Slow" Extinguishers. We consistently found that while DCS reduced relapse in Fast Extinguishers, it had minimal effects on relapse in Slow Extinguishers. Importantly, the differences in the effect of DCS on Fast and Slow Extinguishers was not due to Fast Extinguishers being less susceptible to relapse as animals in both groups exhibited similar amounts of relapse when injected with saline. Relapse, of all three types tested, was consistently reduced by DCS, but only in the Fast Extinguishers. Such findings contribute to a growing literature identifying factors that could influence the efficacy of pharmacological adjuncts to exposure therapy. These results have important implications for the development of personalized treatment approaches, which recognize, and are tailored to, individual differences.

A randomized controlled study of power posing before public speaking exposure for social anxiety disorder: No evidence for augmentative effects

This manuscript details a randomized controlled study designed to test the efficacy of power posing (i.e., briefly holding postures associated with dominance and power) as an augmentative strategy for exposure therapy for social anxiety disorder (SAD). Seventy-three individuals diagnosed with SAD were assigned to one of three conditions: power posing, submissive posing, or rest (no posing) prior to participating in an exposure therapy session. Participants were assessed for between-group differences in pre- and post-manipulation salivary hormone levels, within-session subjective experiences of fear, and pre- and 1-week post-treatment SAD severity outcome measures. Though the intervention resulted in decreased SAD symptom severity one week later, analyses revealed no significant between-group differences on any tested variables. Accordingly, this study provides no evidence to suggest that power posing impacts hormone levels or exposure therapy outcomes.

Effects of acute exercise on fear extinction in rats and exposure therapy in humans: Null findings from five experiments

BACKGROUND

Exposure therapy is an established learning-based intervention for the treatment of anxiety disorders with an average response rate of nearly 50%, leaving room for improvement. Emerging strategies to enhance exposure therapy in humans and fear extinction retention in animal models are primarily pharmacological. These approaches are limited as many patients report preferring non-pharmacological approaches in therapy. With general cognitive enhancement effects, exercise has emerged as a plausible non-pharmacological augmentation strategy. The present study tested the hypothesis that fear extinction and exposure therapy would be enhanced by a pre-training bout of exercise.

METHODS

We conducted four experiments with rats that involved a standardized conditioning and extinction paradigm and a manipulation of exercise. In a fifth experiment, we manipulated vigorous-intensity exercise prior to a standardized virtual reality exposure therapy session among adults with fear of heights.

RESULTS

In experiments 1-4, exercise did not facilitate fear extinction, long-term memory, or fear relapse tests. In experiment 5, human participants showed an overall reduction in fear of heights but exercise did not enhance symptom improvement.

CONCLUSIONS

Although acute exercise prior to fear extinction or exposure therapy, as operationalized in the present 5 studies, did not enhance outcomes, these results must be interpreted within the context of a broader literature that includes positive findings. Taken all together, this suggests that more research is necessary to identify optimal parameters and key individual differences so that exercise can be implemented successfully to treat anxiety disorders.

A Meta-Analysis of D-Cycloserine in Exposure-Based Treatment: Moderators of Treatment Efficacy, Response, and Diagnostic Remission

OBJECTIVE

This meta-analysis examined treatment efficacy, treatment response, and diagnostic remission effect sizes and moderators of D-cycloserine-augmented exposure treatment in randomized controlled trials (RCTs) of individuals with anxiety disorders, obsessive-compulsive disorder (OCD), and posttraumatic stress disorder (PTSD).

DATA SOURCES AND STUDY SELECTION

The terms D-cycloserine AND randomized controlled trial were used to search the PubMed (1965-May 2015), PsycINFO, and Scopus databases for randomized placebo-controlled trials of D-cycloserine-augmented exposure therapy for anxiety disorders, OCD, and PTSD.

DATA EXTRACTION

Clinical variables and effect sizes were extracted from 20 RCTs (957 participants). A random-effects model calculated the effect sizes for treatment efficacy, treatment response, and diagnostic remission using standardized rating scales. Subgroup analyses and meta-regression were used to examine potential moderators.

RESULTS

A small, nonsignificant benefit of D-cycloserine augmentation compared to placebo augmentation was identified across treatment efficacy (g = 0.15), response (risk ratio [RR] = 1.08), and remission (RR = 1.109), with a moderately significant effect (P = .03) for anxiety disorders specifically (g = 0.33). At initial follow-up assessments, a small, nonsignificant effect size of D-cycloserine augmentation compared to placebo was found for treatment efficacy (g = 0.21), response (RR = 1.06), and remission (RR = 1.12). Specific treatment moderators (eg, comorbidity, medication status, gender, publication year) were found across conditions for both acute treatment and initial follow-up assessments.

CONCLUSIONS

D-Cycloserine does not universally enhance treatment outcomes but demonstrates promise for anxiety disorders. Distinct treatment moderators may account for discrepant findings across RCTs and disorders. Future trials may be strengthened by accounting for identified moderators in their design, with ongoing research needed on the mechanisms of D-cycloserine to tailor treatment protocols and maximize its benefit.

New Developments in Cognitive-Behavioral Therapy for Social Anxiety Disorder

Social anxiety disorder (SAD) is a highly prevalent and chronic disorder that causes considerable psychosocial impairment. This article reviews recent changes in the definition of SAD in DSM-5 and summarizes the current evidence for effective cognitive-behavioral treatments in adults, children, and adolescents. Current data suggests that cognitive-behavioral therapy (CBT) is efficacious in the treatment of this condition. Among different CBT approaches, individual cognitive therapy may be associated with the largest effect sizes. In this review, interventions targeting dysfunctional cognitive processes that contribute to the effective treatment of SAD are discussed. Some recent findings from neuroimaging research and studies on the augmentation of CBT using neuroenhancers indicate that changes in emotion regulation as well as fear extinction are important psychological mediators of positive outcome. Furthermore, internet-delivered CBT is a promising field of technological innovation that may improve access to effective treatments. Despite the availability of effective treatments, treatment-resistant SAD remains a common problem in clinical practice that requires more research efforts. Finally, potential areas for further development of CBT as well as its dissemination in health care are summarized.

D-Cycloserine facilitation of exposure therapy improves weight regain in patients with anorexia nervosa: a pilot randomized controlled trial

OBJECTIVE

Exposure therapy in anorexia nervosa has preliminarily been shown to be effective for increasing food intake. D-Cycloserine is a glutamatergic N-methyl-d-aspartate receptor agonist that has been shown to facilitate the benefits of exposure therapy for anxiety disorders by enhancing the emotional learning in the exposures; therefore, we examined D-cycloserine-facilitation of exposure therapy to increase body mass index (BMI) in patients with anorexia nervosa.

METHOD

Participants (N = 36) with anorexia nervosa (diagnosed via DSM-IV) were recruited from a partial hospitalization eating disorder clinic between February 2013 and November 2013. Participants were randomly assigned to receive exposure therapy plus D-cycloserine (n = 20) or placebo (n = 16). Participants completed psychoeducation and 4 sessions of exposure therapy, with medication (D-cycloserine vs placebo) given prior to the first 3 exposure sessions. They also completed a 1-month follow-up.

RESULTS

As hypothesized, participants in the D-cycloserine group showed a significantly greater increase in BMI than those in the placebo group (Wilk Λ = 0.86, F3,32 = 2.20, P = .043, ηp(2) = 0.12). D-Cycloserine participants gained 3 pounds relative to 0.5 pounds in the placebo group. Both groups experienced significantly decreased anxiety over the course of therapy (Wilk Λ = 0.80, F3,32 = 3.32, P = .023, ηp(2) = 0.20).

CONCLUSIONS

This study preliminarily demonstrates that D-cycloserine facilitates exposure therapy for anorexia nervosa, leading to increased weight gain. A potential mechanism is that participants who receive D-cycloserine may generalize learning from within-session exposures to food intake during other similar meals, resulting in sustained increases in BMI. Further research is needed to confirm these findings and test the putative mechanism that generalized learning from exposure therapy can increase BMI and stabilize a healthy weight.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT01996644.

Augmentation of cognitive and behavioural therapies (CBT) with d-cycloserine for anxiety and related disorders

BACKGROUND

A significant number of patients who suffer with anxiety and related disorders (that is post-traumatic stress disorder (PTSD), social anxiety disorder (SAnD), panic disorder with or without agoraphobia (PD), specific phobia (SPh) and obsessive compulsive disorder (OCD)) fail to respond optimally to first-line treatment with medication or cognitive and behavioural therapies. The addition of d-cycloserine (DCS) to cognitive and behavioural therapies may improve treatment response by impacting the glutamatergic system. This systematic review aimed to investigate the effects of adding DCS to cognitive and behavioural therapies by synthesising data from relevant randomised controlled trials and following the guidelines recommended by Cochrane.

OBJECTIVES

To assess the effect of DCS augmentation of cognitive and behavioural therapies compared to placebo augmentation of cognitive and behavioural therapies in the treatment of anxiety and related disorders. Additionally, to assess the efficacy and tolerability of DCS across different anxiety and related disorders.

SEARCH METHODS

This review fully incorporates studies identified from a search of the Cochrane Depression, Anxiety and Neurosis Controlled Trials Register (CCDANCTR) to 12 March 2015. This register includes relevant randomised controlled trials (RCTs) from: the Cochrane Library (all years), EMBASE (1974 to date), MEDLINE (1950 to date), PsycINFO (1967 to date), the World Health Organization's trials portal (ICTRP) and ClinicalTrials.gov . Reference lists from previous meta-analyses and reports of RCTs were also checked. No restrictions were placed on language, setting, date or publication status.

SELECTION CRITERIA

All RCTs of DCS augmentation of cognitive and behavioural therapies versus placebo augmentation of cognitive and behavioural therapies for anxiety and related disorders were included.

DATA COLLECTION AND ANALYSIS

Two authors (RO and TA) independently assessed RCTs for eligibility and inclusion, extracted outcomes and risk of bias data and entered these into a customised extraction form. Investigators were contacted to obtain missing data. In addition, data entry and analysis were performed by two review authors (KSW and HB).

MAIN RESULTS

Twenty-one published RCTs, with 788 participants in outpatient settings, were included in the review. Sixteen studies had an age range of 18 to 75 years, while four investigated paediatric populations aged 8 to 17 years and one included children, adolescents and adults. The 21 RCTs investigated OCD (number of RCTs (N) = 6), PTSD (N = 5), SAnD (N = 5), SPh (N = 3) and PD (N = 2). Most information from the studies was rated as having either low risk or unclear risk of bias.There was no evidence of a difference between DCS augmentation of cognitive and behavioural therapies and placebo augmentation of cognitive and behavioural therapies for the treatment of anxiety and related disorders in adults at the endpoint (treatment responders, N = 9, risk ratio (RR) 1.10; 95% confidence interval (CI) 0.89 to 1.34; number of participants (n) = 449; low quality evidence) and between 1 and 12 months follow-up (N = 7, RR 1.08; 95% CI 0.90 to 1.31; n = 383). DCS augmentation of cognitive and behavioural therapies was not superior to placebo augmentation of cognitive and behavioural therapies for children and adolescents, both at the endpoint (N = 4, RR 1.01; 95% CI 0.78 to 1.31; n = 121; low quality evidence) and between 3 and 12 months follow-up (N = 3, RR 0.86; 95% CI 0.67 to 1.09; n = 91).There was no evidence of a difference in treatment acceptability for DCS augmentation of cognitive and behavioural therapies compared with placebo augmentation of cognitive and behavioural therapies in adults (N = 16, RR 0.88; 95% CI 0.61 to 1.25; n = 740), nor in children and adolescents (N = 4, RR 0.90; 95% CI 0.17 to 4.69; n = 131). These conclusions were based on moderate quality evidence for adults, and very low quality evidence for children and adolescents. Although the observed difference was small, it is noteworthy that there was a high efficacy of exposure-based therapies alone in the included trials. Due to the limited number of studies, subgroup analysis of moderating factors for clinical and methodological effect could not take place.

AUTHORS' CONCLUSIONS

This review found no evidence of a difference between DCS augmentation of cognitive and behavioural therapies and placebo augmentation of cognitive and behavioural therapies for treating anxiety and related disorders in children, adolescents and adults. These findings are based on low quality evidence from heterogenous studies with small sample sizes and incomplete data for clinical response, which precludes us from drawing conclusions on the use of DCS augmentation of cognitive and behavioural therapies at this stage. Given there is some promising preliminary data from individual studies, further research is necessary to assess DCS compared with placebo augmentation of cognitive and behavioural therapies, and determine mechanisms of action as well as magnitude of effect in anxiety and related disorders.

D-cycloserine augmentation of cognitive behavioral therapy for anxiety disorders: an update

Although cognitive behavioral therapy (CBT) is a generally effective treatment for treating anxiety disorders, there is clearly still room for further improvements. Recent advances in neuroscience of extinction learning led to novel clinical strategies to augment exposure-based treatments with d-cycloserine (DCS), a partial agonist at the glycine recognition site of the glutamatergic N-methyl-D-aspartate receptor. This review provides an update on the current knowledge of DCS as an augmentation strategy of CBT for anxiety disorders. The adequacy of the CBT to be augmented, the dose of DCS, and the timing and duration of augmentation efforts all appear to be important moderating variables. Moreover, there is evidence that DCS may also augment fear memory reconsolidation if the fear level remains high after the exposure. Future studies need to examine whether DCS can augment CBT when administered after exposure in order to develop a tailored administration strategy to maximize its clinical utility.

On the Road to Translation for PTSD Treatment: Theoretical and Practical Considerations of the Use of Human Models of Conditioned Fear for Drug Development

The use of quantitative, laboratory-based measures of threat in humans for proof-of-concept studies and target development for novel drug discovery has grown tremendously in the last 2 decades. In particular, in the field of posttraumatic stress disorder (PTSD), human models of fear conditioning have been critical in shaping our theoretical understanding of fear processes and importantly, validating findings from animal models of the neural substrates and signaling pathways required for these complex processes. Here, we will review the use of laboratory-based measures of fear processes in humans including cued and contextual conditioning, generalization, extinction, reconsolidation, and reinstatement to develop novel drug treatments for PTSD. We will primarily focus on recent advances in using behavioral and physiological measures of fear, discussing their sensitivity as biobehavioral markers of PTSD symptoms, their response to known and novel PTSD treatments, and in the case of d-cycloserine, how well these findings have translated to outcomes in clinical trials. We will highlight some gaps in the literature and needs for future research, discuss benefits and limitations of these outcome measures in designing proof-of-concept trials, and offer practical guidelines on design and interpretation when using these fear models for drug discovery.

Enhancing exposure therapy for anxiety disorders, obsessive-compulsive disorder and post-traumatic stress disorder

Translating findings from basic science, several compounds have been identified that may enhance therapeutic outcomes and/or expedite treatment gains when administered alongside exposure-based treatments. Four of these compounds (referred to as cognitive enhancers) have been evaluated in the context of randomized controlled trials for anxiety disorders (e.g., specific phobias, panic disorder, social anxiety disorder), obsessive-compulsive disorder and post-traumatic stress disorder. These cognitive enhancers include D-cycloserine, yohimbine hydrochloride, glucocorticoids and cortisol and brain-derived neurotrophic factor. There is consistent evidence that cognitive enhancers can enhance therapeutic outcomes and/or expedite treatment gains across anxiety disorders, obsessive-compulsive disorder and post-traumatic stress disorder. Emerging evidence has highlighted the importance of within-session fear habituation and between-session fear learning, which can either enhance fear extinction or reconsolidate of fear responses. Although findings from these trials are promising, there are several considerations that warrant further evaluation prior to widespread use of cognitive enhancers in exposure-based treatments. Consistent trial design and large sample sizes are important in future studies of cognitive enhancers.

Prescriptive variables for d-cycloserine augmentation of exposure therapy for posttraumatic stress disorder

In recent years, several studies have demonstrated efficacy of d-cycloserine (DCS) enhanced exposure therapy across anxiety disorders. In this study we examined person-level variables that predicted response to DCS enhanced exposure therapy in a chronic, mixed trauma PTSD sample. The sample consisted of 67 treatment-seeking individuals, randomly allocated to receive exposure therapy augmented with DCS (50 mg) or identical looking placebo. We examined the following baseline predictors of treatment response: (1) demographic characteristics (age, gender, marital status, and education); (2) clinical characteristics (initial PTSD symptom severity, Axis I comorbidity, depression symptom severity, and antidepressants use); (3) personality characteristics (openness, conscientiousness, extraversion, agreeableness, and neuroticism). Outcome was measured with the PTSD Symptom Scale, Self-Report, which was assessed weekly during treatment. Two prescriptive variables were identified: conscientiousness and extraversion. For high conscientious participants, those who received DCS showed better outcome than those who received placebo. And for low extraversion, DCS showed superior outcome relative to placebo. Education was identified as a prognostic variable, it predicted response across both groups: higher education was related to worse outcome. Our results provide support for the influence of personality traits on DCS augmented exposure outcome and give more insight into possible working mechanisms of this novel treatment strategy. Ultimately, this may contribute to treatment matching strategies in order to improve treatment efficacy of exposure therapy for PTSD.

D-Cycloserine as an augmentation strategy for cognitive behavioral therapy of anxiety disorders

The goal of this review is to examine the clinical studies on d-cycloserine, a partial glutamatergic N-methyl-D-aspartate agonist, as an augmentation strategy for exposure procedures during cognitive behavioral therapy for anxiety disorders. Although cognitive behavioral therapy and anxiolytic medications are more effective than placebo for treating anxiety disorders, there is still considerable room for further improvement. Traditional combination strategies typically yield disappointing results. However, recent studies based on translational research have shown promise to augment the neural circuitry underlying fear extinction with pharmacological means. We discuss the current state of the literature, including inconsistencies of findings and issues concerning the drug mechanism, dosing, and dose timing. D-cycloserine is a promising combination strategy for cognitive behavioral therapy of anxiety disorders by augmenting extinction learning. However, there is also evidence to suggest that d-cycloserine can facilitate reconsolidation of fear memory when exposure procedures are unsuccessful.