Management of Treatment-Resistant Panic Disorder

A digital phenotyping dataset for impending panic symptoms: a prospective longitudinal study

This study investigated the utilization of digital phenotypes and machine learning algorithms to predict impending panic symptoms in patients with mood and anxiety disorders. A cohort of 43 patients was monitored over a two-year period, with data collected from smartphone applications and wearable devices. This research aimed to differentiate between the day before panic (DBP) and stable days without symptoms. With RandomForest, GradientBoost, and XGBoost classifiers, the study analyzed 3,969 data points, including 254 DBP events. The XGBoost model demonstrated performance with a ROC-AUC score of 0.905, while a simplified model using only the top 10 variables maintained an ROC-AUC of 0.903. Key predictors of panic events included evaluated Childhood Trauma Questionnaire scores, increased step counts, and higher anxiety levels. These findings indicate the potential of machine learning algorithms leveraging digital phenotypes to predict panic symptoms, thereby supporting the development of proactive and personalized digital therapies and providing insights into real-life indicators that may exacerbate panic symptoms in this population.

Decreased temporal variabilities of functional connectivities in insula and lingual gyrus are associated with better early treatment response in patients with panic disorder

BACKGROUND

Panic disorder is a common disabling condition with limited biomarkers. We aimed to explore the diagnostic and treatment response prediction value of functional temporal variability in people with panic disorder.

METHODS

Patients with panic disorder and healthy controls received resting-state functional magnetic resonance imaging scans and assessments. After 2 weeks of treatment, the patients with panic disorder were divided into remitted (RPD; n = 39) or nonremitted (NRPD; n = 43) subgroups. Baseline temporal variability was analyzed between the panic disorder and control groups as well as between RPD and NRPD subgroups.

RESULTS

Our sample included 82 patients with panic disorder (39 RPD, 43 NRPD) and 105 controls. The panic disorder group showed decreased temporal variability in the left posterior cingulate gyrus (PCG), right lingual gyrus, right fusiform gyrus, and right thalamus (all p < 0.05, Bonferroni-corrected). A combination of variability in the lingual gyrus, PCG, and thalamus had optimal predictive value for distinguishing between the panic disorder and control groups (area under the curve = 0.776, sensitivity = 0.781, specificity = 0.732). In addition, the RPD subgroup showed significantly lower temporal variability in the left insula, right PCG, and bilateral lingual gyrus than the NRPD subgroup and control group (all p < 0.05, Bonferroni-corrected). Variability in the left insula and left lingual gyrus negatively correlated with the reduction rate of panic symptoms (all p < 0.05, Bonferroni-corrected).

LIMITATIONS

Functional brain images were collected only at baseline and may have been affected by medication use. Also, the follow-up period was only 2 weeks; sustained clinical remission may require longer follow-up.

CONCLUSION

Combining lingual gyrus, PCG, and thalamus temporal variability alterations helped distinguish patients with panic disorder from healthy controls. The temporal variability in the insula and lingual gyrus are potential biomarkers for the treatment of panic disorder.

Biochemical challenges for testing novel anti-panic drugs in humans

Current medications for panic disorder each carry significant limitations that indicate the need for novel anxiolytics. The high costs and low success rates of drug development demand that testing trials be efficient. Lab panicogenic challenges in humans allow for the rapid biochemical induction of panic symptoms and hence an efficient means of testing potential anti-panic drugs. This paper describes ideal characteristics of lab panicogens, reviews the validity and utility of various biochemical panicogenic agents, identifies key outcome measures for studies of novel anti-panic drugs, and makes broad recommendations for labs wishing to perform such studies. We conclude by presenting a four-tiered hierarchy of panicogens that matches each against ideal characteristics and reflects our recommendations for their laboratory use.

Discrimination between healthy participants and people with panic disorder based on polygenic scores for psychiatric disorders and for intermediate phenotypes using machine learning

OBJECTIVE

Panic disorder is a modestly heritable condition. Currently, diagnosis is based only on clinical symptoms; identifying objective biomarkers and a more reliable diagnostic procedure is desirable. We investigated whether people with panic disorder can be reliably diagnosed utilizing combinations of multiple polygenic scores for psychiatric disorders and their intermediate phenotypes, compared with single polygenic score approaches, by applying specific machine learning techniques.

METHODS

Polygenic scores for 48 psychiatric disorders and intermediate phenotypes based on large-scale genome-wide association studies (n = 7556-1,131,881) were calculated for people with panic disorder (n = 718) and healthy controls (n = 1717). Discrimination between people with panic disorder and healthy controls was based on the 48 polygenic scores using five methods for classification: logistic regression, neural networks, quadratic discriminant analysis, random forests and a support vector machine. Differences in discrimination accuracy (area under the curve) due to an increased number of polygenic score combinations and differences in the accuracy across five classifiers were investigated.

RESULTS

All five classifiers performed relatively well for distinguishing people with panic disorder from healthy controls by increasing the number of polygenic scores. Of the 48 polygenic scores, the polygenic score for anxiety UK Biobank was the most useful for discrimination by the classifiers. In combinations of two or three polygenic scores, the polygenic score for anxiety UK Biobank was included as one of polygenic scores in all classifiers. When all 48 polygenic scores were used in combination, the greatest areas under the curve significantly differed among the five classifiers. Support vector machine and logistic regression had higher accuracy than quadratic discriminant analysis and random forests. For each classifier, the greatest area under the curve was 0.600 ± 0.030 for logistic regression (polygenic score combinations N = 14), 0.591 ± 0.039 for neural networks (N = 9), 0.603 ± 0.033 for quadratic discriminant analysis (N = 10), 0.572 ± 0.039 for random forests (N = 25) and 0.617 ± 0.041 for support vector machine (N = 11). The greatest areas under the curve at the best polygenic score combination significantly differed among the five classifiers. Random forests had the lowest accuracy among classifiers. Support vector machine had higher accuracy than neural networks.

CONCLUSIONS

These findings suggest that increasing the number of polygenic score combinations up to approximately 10 effectively improved the discrimination accuracy and that support vector machine exhibited greater accuracy among classifiers. However, the discrimination accuracy for panic disorder, when based solely on polygenic score combinations, was found to be modest.

The definition of treatment resistance in anxiety disorders: a Delphi method-based consensus guideline

Anxiety disorders are very prevalent and often persistent mental disorders, with a considerable rate of treatment resistance which requires regulatory clinical trials of innovative therapeutic interventions. However, an explicit definition of treatment-resistant anxiety disorders (TR-AD) informing such trials is currently lacking. We used a Delphi method-based consensus approach to provide internationally agreed, consistent and clinically useful operational criteria for TR-AD in adults. Following a summary of the current state of knowledge based on international guidelines and an available systematic review, a survey of free-text responses to a 29-item questionnaire on relevant aspects of TR-AD, and an online consensus meeting, a panel of 36 multidisciplinary international experts and stakeholders voted anonymously on written statements in three survey rounds. Consensus was defined as ≥75% of the panel agreeing with a statement. The panel agreed on a set of 14 recommendations for the definition of TR-AD, providing detailed operational criteria for resistance to pharmacological and/or psychotherapeutic treatment, as well as a potential staging model. The panel also evaluated further aspects regarding epidemiological subgroups, comorbidities and biographical factors, the terminology of TR-AD vs. "difficult-to-treat" anxiety disorders, preferences and attitudes of persons with these disorders, and future research directions. This Delphi method-based consensus on operational criteria for TR-AD is expected to serve as a systematic, consistent and practical clinical guideline to aid in designing future mechanistic studies and facilitate clinical trials for regulatory purposes. This effort could ultimately lead to the development of more effective evidence-based stepped-care treatment algorithms for patients with anxiety disorders.

Panic disorder in epilepsy

A 51-year-old woman showed structural epilepsy following an atypical, nontraumatic intracranial hemorrhage in the right frontal area. Despite successful seizure control with lamotrigine, she developed severe morning anxiety and panic attacks, leading to agoraphobia, social withdrawal, and psychogenic nonepileptic seizures. Neuropsychiatric and psychological assessments confirmed an anxiety disorder with no significant symptoms of depression. The patient received various psychopharmacological treatments with limited success. This case report illustrates that managing panic disorder in patients with structural epilepsy requires a comprehensive treatment approach that includes pharmacotherapy and psychotherapy. Differential diagnosis and accurate treatment are crucial because of the symptom overlap between panic attacks and peri-ictal fear. Screenings instruments such as the Panic and Agoraphobia Scale (PAS) can aid in assessing anxiety-related symptoms. First-line pharmacotherapy with selective serotonin reuptake inhibitors, especially sertraline, or venlafaxine can effectively reduce panic attacks and can be recommended in patients with epilepsy. Psychotherapy, particularly cognitive-behavioral therapy, is the treatment of choice. Referral to a psychiatrist is indicated when symptoms are severe or refractory to treatment.

A preliminary examination of unified protocol for transdiagnostic treatment of emotional disorders in patients with panic disorder: a single-case experimental design in Iran

BACKGROUND AND OBJECTIVES

The majority of patients suffering from anxiety disorders in low- and middle-income countries do not receive evidence-based treatments. The Unified Protocol (UP) for the Transdiagnostic Treatment of Emotional Disorders is an evidence-based cognitive-behavioral intervention designed to treat the range of emotional disorders.

DESIGN AND METHODS

Using a single-case experimental design five patients with panic disorder were assigned to a 3-week baselines assessment phase followed by eight sessions of UP treatment and 4-week follow-up phases. Multiple outcome measures of panic severity, anxiety sensitivity, affectivity, and overall anxiety severity and impairment were administered weekly during the baseline, intervention, and follow-up phases.

RESULTS

At post treatment, all participants showed significant reductions in outcome measures, with changes functionally related to treatment and most improvements maintained at 4-week follow-up.

CONCLUSION

Findings provide preliminary cross-cultural support for UP and add to the growing body of literature showing UP can be useful for patients with anxiety disorders in low- and middle-income countries with non-Western cultures.

Evaluation of MINOCA syndrome and HEART score in patients presenting to the emergency department with panic attack and chest pain complaints

BACKGROUND

Patients presenting with chest pain may or may not be experiencing a panic attack. Is chest pain caused by a panic attack or myocardial infarction with non-obstructive coronary arteries (MINOCA) syndrome?

AIM

In this study, we evaluated both MINOCA syndrome and HEART score in patients who presented to the emergency department with panic attacks and chest pain.

METHOD

Patients who applied to the emergency department with panic disorder and chest pain complaints were included. Patients who met the MINOCA diagnostic criteria were identified. The study was completed with 143 eligible patients out of a total of 217 patients evaluated. The patients were divided into two groups. The first group was those whose symptoms and test results were consistent with MINOCA. The second group was composed of those whose chest pain was considered non-specific. The HEART score of all patients was calculated. The demographic characteristics, symptoms, and HEART scores were compared between the groups.

RESULTS

Of the 143 patients evaluated in the study, 62 (43.3%) were male and 81 (56.7%) were female. While the mean HEART score was 4.7 ± 1.5 in the MINOCA group, it was 2.0 ± 1.0 in the non-cardiac group, a statistically significant difference.

CONCLUSION

Clinicians should pay attention to the patient's age, gender, number of attacks per week, HEART score, and which symptoms (palpitations, shortness of breath, and fear of death) are present in patients who meet the panic attack diagnostic criteria. Clinicians should be alert to the MINOCA syndrome in panic attack patients.

The efficacy and optimal matching of an Internet-based acceptance and commitment therapy intervention for depressive symptoms among university students: A randomized controlled trial in China

OBJECTIVE

The present study tested the efficacy of an unguided internet-based Acceptance and Commitment Therapy (iACT) program for depression, and identified the psychological characteristics of participants who benefitted the most from the program.

METHOD

Undergraduate students with mild to severe symptoms of depression were randomized to the iACT group (n = 95) or the waiting-list group (WLC group; n = 87). Depressive symptoms and positive mental health were assessed at baseline (T₀ ), at the end of the 6-week program (T₁ ), and at a 3-month follow-up (T₂ ).

RESULTS

Compared with the WLC group, the iACT group showed significantly more improvement in depressive symptoms (d = 1.27) and positive mental health (d = 0.59), both at T₁ and T₂ . Latent Profile Analysis identified three classes of participants: Sensitive-to-Relationship, Low-Reactive-Depression, and Endogenous-Depression group. In general, the treatment was particularly suitable for the Sensitive-to-Relationship class.

CONCLUSION

The iACT was effective in treating the depressive symptoms of undergraduates, especially suitable for the clients with high baseline depression, high externality, high resistance, and high sensitivity to relationships.

Pathological Worry is Related to Poor Long-Term Pharmacological Treatment Response in Patients With Panic Disorder

OBJECTIVE

Several predictors of unfavorable pharmacological treatment response (PTR) in panic disorder (PD) patients have been suggested, such as the duration of the illness, presence of agoraphobia, depression, being a woman, and early trauma. This study aimed to examine whether pathological worry is associated with PTR in PD patients.

METHODS

This study included 335 PD patients and 418 healthy controls (HCs). The Penn State Worry Questionnaire (PSWQ), the Early Trauma Inventory Self Report-Short Form (ETISR-SF), Beck Depression Inventory (BDI), Panic Disorder Severity Scale (PDSS), and Anxiety Sensitivity Inventory-Revised (ASI-R) were administered. We measured the PTR at 8 weeks and 6 months. Student t-test, chisquare tests, Pearson's correlation analyses, and binary logistic regression model were used.

RESULTS

Our results showed that the total scores of the PSWQ correlated with the ETISR-SF, BDI, and ASI-R were significantly higher in patients with PD compared with HCs. The PSWQ and BDI could predict unfavorable PTR at 6 months in PD patients.

CONCLUSION

This is the first study to demonstrate that pathological worry may contribute to poor long-term PTR in PD patients. Therefore, our research suggests that clinicians must be aware of worry to optimize PTR for PD patients.

Experimental Drugs for Panic Disorder: An Updated Systematic Review

Several effective pharmacological therapies for panic disorder (PD) are available, but they have some drawbacks, and unsatisfactory outcomes can occur. Expanding the variety of anti-panic medications may allow for improving PD treatment. The authors performed an updated systematic review of preclinical and clinical (Phase I–III) pharmacological studies to look for advances made in the last six years concerning novel-mechanism-based anti-panic compounds or using medications approved for nonpsychiatric medical conditions to treat PD. The study included seven published articles presenting a series of preclinical studies, two Phase I clinical studies with orexin receptor (OXR) antagonists, and two clinical studies investigating the effects of D-cycloserine (DCS) and xenon gas in individuals with PD. The latest preclinical findings confirmed and expanded previous promising indications of OXR1 antagonists as novel-mechanism-based anti-panic compounds. Translating preclinical research into clinical applications remains in the early stages. However, limited clinical findings suggested the selective OXR1 antagonist JNJ-61393115 may exert anti-panic effects in humans. Overall, OXR1 antagonists displayed a favorable profile of short-term safety and tolerability. Very preliminary suggestions of possible anti-panic effects of xenon gas emerged but need confirmation with more rigorous methodology. DCS did not seem promising as an enhancer of cognitive-behavioral therapy in PD. Future studies, including objective panic-related physiological parameters, such as respiratory measures, and expanding the use of panic vulnerability biomarkers, such as hypersensitivity to CO₂ panic provocation, may allow for more reliable conclusions about the anti-panic properties of new compounds.

Initial white matter connectivity differences between remitters and non-remitters of patients with panic disorder after 6 months of pharmacotherapy

Panic disorder (PD) is a harmful mental condition that causes relapsed and persistent impairment. In the treatment of PD, the prognosis for PD should be considered. However, the relationship between pharmacotherapy and biomarkers, for predicting a better response through neuroimaging, is a little known. The purpose of the present study was to examine whether there would be the initial white matter (WM) regions associated with the remission in 6 months. A total of 104 patients with PD were investigated in the study. After six months, there were 17 remission patients with PD and 81 non-remission patients. The Panic Disorder Severity Scale, Albany Panic and Phobia Questionnaire, Anxiety Sensitivity Inventory-Revised, Beck Anxiety Inventory, and Beck Depression Inventory were assessed for all patients at baseline. We compared the diffusion indices between remission and non-remission group at 6 months using Tract-Based Spatial Statistics. The results showed that the fractional anisotropy (FA) values were significantly higher in the non-remitter group compared with those in the remitter group in the WM regions, such as the posterior corona radiata and superior longitudinal fasciculus, at the 6 month evaluation. The logistic regression analysis with clinical symptom severity and FA values of the WM regions as covariates showed that FA values in those regions and the Beck Depression Inventory-II predicted poor remission. This study suggests that posterior corona radiata and superior longitudinal fasciculus are related to potential predictive factors of 6-month remission in patients with PD. WM regions associated with the long-term remission should be verified with further investigations.

Early Trauma Is Associated with Poor Pharmacological Treatment Response in Patients with Panic Disorder

OBJECTIVE

Pharmacotherapy is established as an effective method for reducing symptoms of panic disorder (PD). However, about 20-40% of PD patients are treatment-resistant. Predictors of pharmacotherapy outcomes for PD patients are needed.

METHODS

This study included 152 PD patients to measure the clinical severities of PD symptoms and used the Early Trauma Inventory (ETI) to measure early trauma. Treatment response was defined as a 40% reduction in the total Panic Disorder Severity Scale score from baseline. We measured the treatment responses at 8 weeks and 6 months. Binary logistic regression was used to predict treatment response after controlling for confounding variables.

RESULTS

Early sexual trauma alone was associated with poor treatment response at 8 weeks. However, at 6 months, the total ETI score was associated with an unfavorable treatment response.

CONCLUSION

Therefore, our study suggests that clinicians need to be aware of a history of early trauma to optimize treatment outcomes for PD patients.

Cognitive-behavioural therapy for a variety of conditions: an overview of systematic reviews and panoramic meta-analysis

BACKGROUND

Cognitive-behavioural therapy aims to increase quality of life by changing cognitive and behavioural factors that maintain problematic symptoms. A previous overview of cognitive-behavioural therapy systematic reviews suggested that cognitive-behavioural therapy was effective for many conditions. However, few of the included reviews synthesised randomised controlled trials.

OBJECTIVES

This project was undertaken to map the quality and gaps in the cognitive-behavioural therapy systematic review of randomised controlled trial evidence base. Panoramic meta-analyses were also conducted to identify any across-condition general effects of cognitive-behavioural therapy.

DATA SOURCES

The overview was designed with cognitive-behavioural therapy patients, clinicians and researchers. The Cochrane Library, MEDLINE, EMBASE, PsycINFO, Cumulative Index to Nursing and Allied Health Literature, Child Development & Adolescent Studies, Database of Abstracts of Reviews of Effects and OpenGrey databases were searched from 1992 to January 2019.

REVIEW METHODS

Study inclusion criteria were as follows: (1) fulfil the Centre for Reviews and Dissemination criteria; (2) intervention reported as cognitive-behavioural therapy or including one cognitive and one behavioural element; (3) include a synthesis of cognitive-behavioural therapy trials; (4) include either health-related quality of life, depression, anxiety or pain outcome; and (5) available in English. Review quality was assessed with A MeaSurement Tool to Assess systematic Reviews (AMSTAR)-2. Reviews were quality assessed and data were extracted in duplicate by two independent researchers, and then mapped according to condition, population, context and quality. The effects from high-quality reviews were pooled within condition groups, using a random-effect panoramic meta-analysis. If the across-condition heterogeneity was I2 < 75%, we pooled across conditions. Subgroup analyses were conducted for age, delivery format, comparator type and length of follow-up, and a sensitivity analysis was performed for quality.

RESULTS

A total of 494 reviews were mapped, representing 68% (27/40) of the categories of the International Classification of Diseases, Eleventh Revision, Mortality and Morbidity Statistics. Most reviews (71%, 351/494) were of lower quality. Research on older adults, using cognitive-behavioural therapy preventatively, ethnic minorities and people living outside Europe, North America or Australasia was limited. Out of 494 reviews, 71 were included in the primary panoramic meta-analyses. A modest effect was found in favour of cognitive-behavioural therapy for health-related quality of life (standardised mean difference 0.23, 95% confidence interval 0.05 to 0.41, prediction interval -0.05 to 0.50, I2 = 32%), anxiety (standardised mean difference 0.30, 95% confidence interval 0.18 to 0.43, prediction interval -0.28 to 0.88, I2 = 62%) and pain (standardised mean difference 0.23, 95% confidence interval 0.05 to 0.41, prediction interval -0.28 to 0.74, I2 = 64%) outcomes. All condition, subgroup and sensitivity effect estimates remained consistent with the general effect. A statistically significant interaction effect was evident between the active and non-active comparator groups for the health-related quality-of-life outcome. A general effect for depression outcomes was not produced as a result of considerable heterogeneity across reviews and conditions.

LIMITATIONS

Data extraction and analysis were conducted at the review level, rather than returning to the individual trial data. This meant that the risk of bias of the individual trials could not be accounted for, but only the quality of the systematic reviews that synthesised them.

CONCLUSION

Owing to the consistency and homogeneity of the highest-quality evidence, it is proposed that cognitive-behavioural therapy can produce a modest general, across-condition benefit in health-related quality-of-life, anxiety and pain outcomes.

FUTURE WORK

Future research should focus on how the modest effect sizes seen with cognitive-behavioural therapy can be increased, for example identifying alternative delivery formats to increase adherence and reduce dropout, and pursuing novel methods to assess intervention fidelity and quality.

STUDY REGISTRATION

This study is registered as PROSPERO CRD42017078690.

FUNDING

This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 25, No. 9. See the NIHR Journals Library website for further project information.

Relapse prevention in panic disorder with pharmacotherapy: where are we now?

Introduction: A substantial number of patients with PD experience relapse after the discontinuation of effective pharmacotherapy, leading to detrimental effects on the individuals and considerable societal costs. This suggests the need to optimize pharmacotherapy to minimize relapse risk. Area covered: The present systematic review examines randomized, double-blind, placebo-controlled relapse prevention studies published over the last 20 years involving recommended medications. The authors aim to provide an overview of this topic and evaluate whether recent advances were achieved. Only seven studies were included, providing limited results. One-year maintenance pharmacotherapy with constant doses had protective effects against relapse in patients who had previously exhibited satisfactory responses to the same medication at the same doses. The duration of maintenance treatment did not influence relapse risk. No data were available concerning the use of lower doses or the predictors of relapse. Expert opinion: Relapse prevention in PD has received limited attention. Recent progress and conclusive indications are lacking. Rethinking pharmacological research in PD may be productive. Collecting a wide range of clinical and individual features/biomarkers in large-scale, multicenter long-term naturalistic studies, and implementing recent technological innovations (e.g., electronic medical records/'big data' platforms, wearable devices, and machine learning techniques) may help identify reliable predictive models.

Aligning the many definitions of treatment resistance in anxiety disorders: A systematic review

Anxiety Disorders often show a chronic course, even when treated with one of the various effective treatments available. Lack of treatment effect could be due to Treatment Resistance (TR). Consensus on a definition for TR Anxiety Disorders (TR-AD) is highly needed as currently many different operationalizations are in use. Therefore, generalizability in current TR-AD research is suboptimal, hampering improvement of clinical care. The objective of this review is to evaluate the currently used definitions of TR-AD by performing a systematic review of available literature. Out of a total of n = 13 042, 62 studies that operationalized TR-AD were included. The current review confirms a lack of consensus on TR-AD criteria. In 62.9% of the definitions, TR was deemed present after the first treatment failure. Most studies (93.0%) required pharmacological treatment failures, whereas few (29.0%) required psychological treatment failures. However, criteria for what constitutes "treatment failure" were not provided in the majority of studies (58.1%). Definitions for minimal treatment duration ranged from at least 4 weeks to at least 6 months. Almost half of the TR-AD definitions (46.8%) required elevated anxiety severity levels in TR-AD. After synthesis of the results, the consensus definition considers TR-AD present after both at least one first-line pharmacological and one psychological treatment failure, provided for an adequate duration (at least 8 weeks) with anxiety severity remaining above a specified threshold. This definition could contribute to improving course prediction and identifying more targeted treatment options for the highly burdened subgroup of TR-AD patients.

Toward a personalized therapy for panic disorder: preliminary considerations from a work in progress

Although several treatment options for panic disorder (PD) are available, the best intervention for each individual patient remains uncertain and the use of a more personalized therapeutic approach in PD is required. In clinical practice, clinicians combine general scientific information and personal experience in the decision-making process to choose a tailored treatment for each patient. In this sense, clinicians already use a somehow personalized medicine strategy. However, the influence of their interpretative personal models may lead to bias related to personal convictions, not sufficiently grounded on scientific evidence. Hence, an effort to give some advice based on the science of personalized medicine could have positive effects on clinicians' decisions. Based on a narrative review of meta-analyses, systematic reviews, and experimental studies, we proposed a first-step attempt of evidence-based personalized therapy for PD. We focused on some phenomenological profiles, encompassing symptoms during/outside panic attacks, related patterns of physiological functions, and some aspects of physical health, which might be worth considering when developing treatment plans for patients with PD. We considered respiratory, cardiac, vestibular, and derealization/depersonalization profiles, with related implications for treatment. Given the extensiveness of the topic, we considered only medications and some somatic interventions. Our proposal should be considered neither exhaustive nor conclusive, as it is meant as a very preliminary step toward a future, robust evidence-based personalized therapy for PD. Clearly much more work is needed to achieve this goal, and recent technological advances, such as wearable devices, big data platforms, and the application of machine learning techniques, may help obtain reliable findings. We believe that combining the efforts of different research groups in this work in progress can lead to largely shared conclusions in the near future.

The role of acid-sensitive ion channels in panic disorder: a systematic review of animal studies and meta-analysis of human studies

Acid-sensitive ion channels, such as amiloride-sensitive cation channel (ACCN), transient receptor potential vanilloid-1 (TRPV1), and T-cell death-associated gene 8 (TDAG8) are highly related to the expression of fear and are expressed in several regions of the brain. These molecules can detect acidosis and maintain brain homeostasis. An important role of pH homeostasis has been suggested in the physiology of panic disorder (PD), with acidosis as an interoceptive trigger for panic attacks. To examine the effect of acid-sensitive channels on PD symptoms, we conducted a systematic review and meta-analysis of these chemosensors in rodents and humans. Following PRISMA guidelines, we systematically searched the Web of Science, Medline/Pubmed, Scopus, Science Direct, and SciELO databases. The review included original research in PD patients and animal models of PD that investigated acid-sensitive channels and PD symptoms. Studies without a control group, studies involving patients with a comorbid psychiatric diagnosis, and in vitro studies were excluded. Eleven articles met the inclusion criteria for the systematic review. The majority of the studies showed an association between panic symptoms and acid-sensitive channels. PD patients appear to display polymorphisms in the ACCN gene and elevated levels of TDAG8 mRNA. The results showed a decrease in panic-like symptoms after acid channel blockade in animal models. Despite the relatively limited data on this topic in the literature, our review identified evidence linking acid-sensitive channels to PD in humans and preclinical models. Future research should explore possible underlying mechanisms of this association, attempt to replicate the existing findings in larger populations, and develop new therapeutic strategies based on these biological features.

Are there advances in pharmacotherapy for panic disorder? A systematic review of the past five years

INTRODUCTION

Several effective medications are available for treating panic disorder (PD). However, outcomes are unsatisfactory in a number of patients, suggesting the usefulness of expanding the array of antipanic drugs and improving the quality of response to current recommended treatments.

AREAS COVERED

The authors have performed an updated systematic review of pharmacological studies (phase III onwards) to examine whether advances have been made in the last five years. Only four studies were included. D-cycloserine no longer seemed promising as a cognitive-behavioral therapy (CBT) enhancer. Some preliminary findings concerning the optimization of recommended medications deserved consideration, including: the possibility that SSRIs are more effective than CBT alone in treating panic attacks, combined therapy is preferable when agoraphobia is present, and clonazepam is more potent than paroxetine in decreasing panic relapse.

EXPERT OPINION

Given the lack of novel treatments, expanding a personalized approach to the existing medications seems to be the most feasible strategy to improve pharmacotherapy outcomes regarding PD. Recent technological progress, including wearable devices collecting real-time data, 'big data' platforms, and application of machine learning techniques might help make outcome prediction more reliable. Further research on previously promising novel treatments is also recommended.

Is panic disorder a disorder of physical fitness? A heuristic proposal

Currently, panic disorder (PD) is considered a mental disorder based on the assumptions that panic attacks (PAs) are “false alarms” that arise from abnormally sensitive defense systems in the central nervous system and that PD is treated with therapies specifically acting on anxiety or fear mechanisms. This article aims to propose an alternative perspective based on the results of some experimental studies. Our heuristic proposal suggests not only that PD may be a mental disorder but also that patients with PD have real abnormal body functioning, mainly involving cardiorespiratory and balance systems, leading to a decline in global physical fitness. PAs, as well as physical symptoms or discomfort in some environmental situations, may be “real alarms” signaling that the adaptability resources of an organism are insufficient to respond appropriately to some internal or external changes, thus representing the transient conscious awareness of an imbalance in body functioning. The antipanic properties of several modern treatments for PD may include their beneficial effects on body functions. Although anxiety or fear mechanisms are evidently involved in PD, we hypothesize that a reduction of physical fitness is the “primum movens” of PD, while anxiety or fear is induced and sustained by repeated signals of impaired body functioning. We propose considering panic in a broader perspective that offers a central role to the body and to contemplate the possible role of somatic treatments in PD.