IDENTIFYING PANIC DISORDER SUBTYPES USING FACTOR MIXTURE MODELING

Biological and cognitive theories explaining panic disorder: A narrative review

The current narrative review summarizes and examines several theories of panic disorder (PD) including biological theories, encompassing neurochemical factors, metabolic and genetic theories, respiratory and hyperventilation theories and cognitive theory. Biological theories have informed the development of psychopharmacological treatments; however, they may be limited in their utility given the efficacy of psychological treatments. In particular, behavioral and, more recently, cognitive models have garnered support due to the efficacy of cognitive-behavior therapy (CBT) in treating PD. The role of combination treatments has been found to be superior in the treatment of PD in particular cases, lending support for the need for an integrated approach and model for PD given that the etiology of PD is complex and multifactorial.

Psychological risk factors and the course of depression and anxiety disorders: A review of 15 years NESDA research

BACKGROUND

The Netherlands Study of Depression and Anxiety (NESDA; N_baseline=2981) is an ongoing longitudinal, multi-site, naturalistic, cohort study examining the etiology, course, and consequences of depression and anxiety. In this article we synthesize and evaluate fifteen years of NESDA research on prominent psychological risk factors for the onset, persistence, recurrence, and comorbidity of affective disorders.

METHODS

A narrative review of 62 NESDA articles examining the specificity and predictive value of neuroticism, behavioral inhibition, repetitive negative thinking, experiential avoidance, cognitive reactivity, locus of control, (implicit) self-esteem, (implicit) disorder-specific self-associations, and attentional bias for the course of affective disorders.

RESULTS

All self-reported risk factors showed cross-sectional relationships with singular and comorbid affective disorders, and prospective relationships with the development and chronicity of depression and anxiety disorders. High neuroticism, low self-esteem, and negative repetitive thinking showed most prominent transdiagnostic relationships, whereas cognitive reactivity showed most pronounced depression-specific associations. Implicit self-esteem showed predictive validity for the persistence and recurrence of anxiety and depression over and above self-reported risk factors. Automatic approach-avoidance behavior and attentional bias for negative, positive, or threat words showed no relationship with affective disorders.

CONCLUSION

NESDA identified both (a) transdiagnostic factors (e.g., neuroticism, low implicit self-esteem, repetitive negative thinking) that may help explain the comorbidity between affective disorders and overlap in symptoms, and (b) indications for disorder-specific risk factors (e.g., cognitive responsivity) which support the relevance of distinct disorder categories and disorder-specific mechanisms. Thus, the results point to the relevance of both transdiagnostic and disorder-specific targets for therapeutic interventions.

Understanding the Life, Pain, and Barriers to Physical Activity in Korean Patients with Panic Disorder: Photovoice Inquiry

Purpose: This study attempted to understand the life, pain, and barriers to physical activity in the daily life of patients with panic disorder (PD). It aimed to provide specific evidence to promote physical activity for patients, suggesting that suitable physical activity strategies for patients with PD would be of value. Methods: Seven patients were invited to participate in a photovoice study. Photovoice is one example of participatory action research. Results: This study inductively identified two main themes: the life and pain of patients with PD and perceived barriers to participate in physical activity by patients with panic disorder. Conclusion: Based on a specific understanding of the population, this study attempted to provide evidence why patients with panic disorder need appropriate physical-activity-promoting strategies.

Emotional processing in panic disorder and its subtypes: An fMRI study using emotional faces

BACKGROUND

Inconsistent findings regarding the pathophysiology of panic disorder (PD) could result from clinical heterogeneity. Identifying subtypes could enhance insights into the neurobiological substrates of PD.

METHODS

An emotional faces fMRI paradigm was used in a group of PD patients (n = 73) and healthy controls (n = 58). The overall PD group was further divided into three previously identified subtypes: a cognitive-autonomic (n = 22), an autonomic (n = 16) and an aspecific (n = 35) subtype. Differences in brain activity levels in response to emotional facial expressions between groups were examined for six regions of interests, namely the amygdala, ventromedial prefrontal cortex, anterior cingulate, fusiform gyrus, lingual gyrus and insula.

RESULTS

PD patients showed lower activity in the rostral anterior cingulate in response to angry faces than healthy controls, which was mainly driven by the autonomic subtype. No significant differences were found in other brain regions when comparing PD patients with controls or when comparing across PD subtypes.

LIMITATIONS

Sample sizes in subgroups were relatively small CONCLUSIONS: The role of the rostral anterior cingulate cortex for emotional processes critical in panic disorder is highlighted by this study and provides, albeit preliminary, evidence for the use of a subtype approach to advance our neurobiological insights in PD considering its involvement in the appraisal of autonomic viscero-sensory symptoms.

The Mediating Effect of Insomnia on the Relationship between Panic Symptoms and Depression in Patients with Panic Disorder

BACKGROUND

This study aimed to determine if sleep disturbances may mediate the relationship between panic symptoms and depression in patients with panic disorder (PD).

METHODS

Electronic medical records were retrospectively reviewed for 110 consecutive patients with diagnosed PD in an outpatient clinic between October 2018 and December 2019. Measurements include the PD Severity Scale, Beck Depression Inventory-II (BDI-II) and Insomnia Severity Index (ISI). Statistical analyses were performed to assess any potential relationship between PD, insomnia and depression.

RESULTS

Of the PD patients, 88 (80%) and 89 (80.9%) had comorbid depression (BDI-II ≥ 14) and insomnia (Korean version of the ISI ≥ 8), respectively. In a mediation model using insomnia as the mediating variable, the total effect of panic symptom severity on depression was significant (t = 7.23, P < 0.001). There were significant effects of panic symptoms on insomnia (t = 4.62, P < 0.001) and of insomnia on depression (t = 6.69, P < 0.001). The main effect of panic symptom severity on depression was also significant, after controlling for the effect of insomnia (t = 5.10, P < 0.001), suggesting partial mediation.

CONCLUSION

Both depressive symptoms and insomnia are common in patients with PD and depression was partially mediated by insomnia in these patients. These results suggest that an intervention for insomnia in patients with PD might help prevent the development of depression.

Panic disorder respiratory subtype: psychopathology and challenge tests - an update

Panic disorder (PD) pathophysiology is very heterogeneous, and the discrimination of distinct subtypes could be very useful. A subtype based on respiratory symptoms is known to constitute a specific subgroup. However, evidence to support the respiratory subtype (RS) as a distinct subgroup of PD with a well-defined phenotype remains controversial. Studies have focused on characterization of the RS based on symptoms and response to CO2. In this line, we described clinical and biological aspects focused on symptomatology and CO2 challenge tests in PD RS. The main symptoms that characterize RS are dyspnea (shortness of breath) and a choking sensation. Moreover, patients with the RS tended to be more responsive to CO2 challenge tests, which triggered more panic attacks in this subgroup. Future studies should focus on discriminating respiratory-related clusters and exploring psychophysiological and neuroimaging outcomes in order to provide robust evidence to confirm RS as a distinct subtype of PD.

Diagnostic Utility of Sodium Lactate Infusion and CO2-35% Inhalation for Panic Disorder

Laboratory measures have played an integral role in diagnosing pathology; however, compared to traditional medicine, psychiatric medicine has lagged behind in using such measures. A growing body of literature has begun to examine the viability and development of different laboratory measures in order to diagnose psychopathologies. The present review examines the current state of development of both sodium lactate infusion and CO2-35% inhalation as potential ancillary measures to diagnose panic disorder (PD). A previously established 3-step approach to identifying laboratory-based diagnostic tests was applied to available literature assessing the ability of both sodium lactate infusion or CO2-35% inhalation to induce panic attacks in PD patients, healthy controls, and individuals with other psychiatric conditions. Results suggest that across the literature reviewed, individuals with PD were more likely to exhibit panic attacks following administration of sodium lactate or CO2-35% compared to control participants. The majority of the studies examined only compared individuals with PD to healthy controls, suggesting that these ancillary measures are underdeveloped. In order to further determine the utility of these ancillary measures, research is needed to determine if panic attacks following administration of these chemical agents are unique to PD, or if individuals with related pathologies also respond, which may be indicative of transdiagnostic characteristics found across disorders.

Does Personality Matter? Temperament and Character Dimensions in Panic Subtypes

Introduction

Symptomatic heterogeneity in the clinical presentation of Panic Disorder (PD) has lead to several attempts to identify PD subtypes; however, no studies investigated the association between temperament and character dimensions and PD subtypes. The study was aimed to verify whether personality traits were differentially related to distinct symptom dimensions.

Methods

Seventy-four patients with PD were assessed by the Mini-International Neuropsychiatric Interview (M.I.N.I.), and the Temperament and Character Inventory (T.C.I.). Thirteen panic symptoms from the M.I.N.I. were included in a factor analysis with varimax rotation. A correlation analysis (Pearson's correlation), a linear regression analysis, and a forward stepwise regression analysis between the identified factors and T.C.I. variables were performed for evaluating the association between panic subtypes and personality features.

Results

Three factors were obtained: "Somato-dissociative", "Respiratory", and "Cardiologic" explaining respectively 18.31%, 13.71%, and 12.78% of the total variance. Correlations analyses showed that only "Somato-dissociative" factor was significantly correlated with T.C.I. "Self-directedness" (p<0.0001) and "Cooperativeness" (p=0.009) variables. Results from the regression analysis indicate that the predictor models account for 33.3% and 24.7% of the total variance respectively in "Somatic-dissociative" (p<0.0001) and "Cardiologic" (p=0.007) factors, while they do not show statistically significant effects on "Respiratory" factor (p=0.222). After performing stepwise regression analysis, "Self-directedness" resulted the unique predictor of "Somato-dissociative" factor (R²=0.186; β=-0.432; t=-4.061; p<0.0001).

Conclusion

Current results, although preliminary, suggest the importance of assessing personality and temperament features that may be potentially related to poor treatment response for a better understanding and characterization of PD subtypes.

Using a hybrid subtyping model to capture patterns and dimensionality of depressive and anxiety symptomatology in the general population

BACKGROUND

Researchers have tried to identify more homogeneous subtypes of major depressive disorder (MDD) with latent class analyses (LCA). However, this approach does no justice to the dimensional nature of psychopathology. In addition, anxiety and functioning-levels have seldom been integrated in subtyping efforts. Therefore, this study used a hybrid discrete-dimensional approach to identify subgroups with shared patterns of depressive and anxiety symptomatology, while accounting for functioning-levels.

METHODS

The Comprehensive International Diagnostic Interview (CIDI) 1.1 was used to assess previous-year depressive and anxiety symptoms in the Netherlands Mental Health Survey and Incidence Study-1 (NEMESIS-1; n=5583). The data were analyzed with factor analyses, LCA and hybrid mixed-measurement item response theory (MM-IRT) with and without functioning covariates. Finally, the classes' predictors (measured one year earlier) and outcomes (measured two years later) were investigated.

RESULTS

A 3-class MM-IRT model with functioning covariates best described the data and consisted of a 'healthy class' (74.2%) and two symptomatic classes ('sleep/energy' [13.4%]; 'mood/anhedonia' [12.4%]). Factors including older age, urbanicity, higher severity and presence of 1-year MDD predicted membership of either symptomatic class vs. the healthy class. Both symptomatic classes showed poorer 2-year outcomes (i.e. disorders, poor functioning) than the healthy class. The odds of MDD after two years were especially increased in the mood/anhedonia class.

LIMITATIONS

Symptoms were assessed for the past year whereas current functioning was assessed.

CONCLUSIONS

Heterogeneity of depression and anxiety symptomatology are optimally captured by a hybrid discrete-dimensional subtyping model. Importantly, accounting for functioning-levels helps to capture clinically relevant interpersonal differences.

Panic Disorder Comorbidity with Medical Conditions and Treatment Implications

Panic disorder (PD) is unique among the anxiety disorders in that panic symptoms are primarily of a physical nature. Consequently, comorbidity with medical illness is significant. This review examines the association between PD and medical illness. We identify shared pathophysiological and psychological correlates and illustrate how physiological activation in panic sufferers underlies their symptom experience in the context of the fight-or-flight response and beyond a situation-specific response pattern. We then review evidence for bodily symptom perception accuracy in PD. Prevalence of comorbidity for PD and medical illness is presented, with a focus on respiratory and cardiovascular illness, irritable bowel syndrome, and diabetes, followed by an outline for potential pathways of a bidirectional association. We conclude by illustrating commonalities in mediating mechanistic pathways and moderating risk factors across medical illnesses, and we discuss implications for diagnosis and treatment of both types of conditions.

World Health Organization disability assessment schedule 2.0: An international systematic review

PURPOSE

This systematic review examines research and practical applications of the World Health Organization Disability Assessment Schedule (WHODAS 2.0) as a basis for establishing specific criteria for evaluating relevant international scientific literature. The aims were to establish the extent of international dissemination and use of WHODAS 2.0 and analyze psychometric research on its various translations and adaptations. In particular, we wanted to highlight which psychometric features have been investigated, focusing on the factor structure, reliability, and validity of this instrument.

METHOD

Following Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) methodology, we conducted a search for publications focused on "whodas" using the ProQuest, PubMed, and Google Scholar electronic databases.

RESULTS

We identified 810 studies from 94 countries published between 1999 and 2015. WHODAS 2.0 has been translated into 47 languages and dialects and used in 27 areas of research (40% in psychiatry).

CONCLUSIONS

The growing number of studies indicates increasing interest in the WHODAS 2.0 for assessing individual functioning and disability in different settings and individual health conditions. The WHODAS 2.0 shows strong correlations with several other measures of activity limitations; probably due to the fact that it shares the same disability latent variable with them. Implications for Rehabilitation WHODAS 2.0 seems to be a valid, reliable self-report instrument for the assessment of disability. The increasing interest in use of the WHODAS 2.0 extends to rehabilitation and life sciences rather than being limited to psychiatry. WHODAS 2.0 is suitable for assessing health status and disability in a variety of settings and populations. A critical issue for rehabilitation is that a single "minimal clinically important .difference" score for the WHODAS 2.0 has not yet been established.

Treatment-resistant panic disorder: clinical significance, concept and management

Panic disorder is commonly prevalent in the population, but the treatment response for panic disorder in clinical practice is much less effective than that in our imagination. Increasing evidence suggested existence of a chronic or remitting-relapsing clinical course in panic disorder. In this systematic review, we re-examine the definition of treatment-resistant panic disorder, and present the potential risk factors related to the treatment resistance, including the characteristics of panic disorder, other psychiatric and physical comorbidities, and psychosocial stresses. Furthermore, we summarize the potential pathophysiologies, such as genetic susceptibility, altered brain functioning, brain-derived neurotrophic factor, and long-term inflammation, to explain the treatment resistance. Finally, we conclude the current therapeutic strategies for treating treatment-resistant panic disorder from pharmacological and non-pharmacological views.

Beyond Lumping and Splitting: A Review of Computational Approaches for Stratifying Psychiatric Disorders

Heterogeneity is a key feature of all psychiatric disorders that manifests on many levels, including symptoms, disease course, and biological underpinnings. These form a substantial barrier to understanding disease mechanisms and developing effective, personalized treatments. In response, many studies have aimed to stratify psychiatric disorders, aiming to find more consistent subgroups on the basis of many types of data. Such approaches have received renewed interest after recent research initiatives, such as the National Institute of Mental Health Research Domain Criteria and the European Roadmap for Mental Health Research, both of which emphasize finding stratifications that are based on biological systems and that cut across current classifications. We first introduce the basic concepts for stratifying psychiatric disorders and then provide a methodologically oriented and critical review of the existing literature. This shows that the predominant clustering approach that aims to subdivide clinical populations into more coherent subgroups has made a useful contribution but is heavily dependent on the type of data used; it has produced many different ways to subgroup the disorders we review, but for most disorders it has not converged on a consistent set of subgroups. We highlight problems with current approaches that are not widely recognized and discuss the importance of validation to ensure that the derived subgroups index clinically relevant variation. Finally, we review emerging techniques-such as those that estimate normative models for mappings between biology and behavior-that provide new ways to parse the heterogeneity underlying psychiatric disorders and evaluate all methods to meeting the objectives of such as the National Institute of Mental Health Research Domain Criteria and Roadmap for Mental Health Research.