Panic disorder and subthreshold panic in the UK general population: Epidemiology, comorbidity and functional limitation

Panic disorder: Epidemiology, disability, and treatment gap from nationally representative general population of India

Introduction

Panic disorder (PD) is one of the most common and debilitating anxiety disorder. Individuals with PD seek frequent healthcare and emergency services leading to frequent work absenteeism and economic burden. However, its prevalence patterns in the Indian context are poorly understood. Hence, this article discusses the epidemiology, disability, and treatment gap from India's National Mental Health Survey 2016.

Materials and Methods

National Mental Health Survey 2016 was a nationally representative epidemiological survey of adult respondents from 12 states of India. Mini International Neuropsychiatric Interview 6.0.0 is used to diagnose psychiatric disorders. Sheehan disability scale was used to assess the disability. The current weighted prevalence of PD was estimated. Association between PD and its sociodemographic correlates was done using Firth penalized logistic regression. The treatment gap and disability in PD were also calculated.

Results

The lifetime and current weighted prevalence of PD was 0.5% (95% confidence interval 0.49-0.52) and 0.3% (95% confidence interval 0.28-0.41), respectively. The male gender and unemployed have significantly lesser odds with current PD. The elderly, Urban metro, and the married/separated group have significantly higher odds with current PD. The most common comorbid psychiatric disorder is agoraphobia (42.3%) and depression (30.9%) followed by Generalized Anxiety Disorder (10%). Among respondents with current PD in the past 1 month across three domains, around 80% had a disability of any severity and 20%-25% had marked disability. The overall treatment gap of current PD is 71.7%.

Conclusion

It is the first study reporting prevalence from a nationally representative sample from the general population of India. The survey has shed light on the epidemiology and the challenges faced by those with PD which emphasizes the urgency of bridging the treatment gap. These findings are paramount to the development of more inclusive and effective mental health policies and interventions to tackle the current burden due to PD.

Two-channel EEG based diagnosis of panic disorder and major depressive disorder using machine learning and non-linear dynamical methods

The current study aimed to investigate the possibility of rapid and accurate diagnoses of Panic disorder (PD) and Major depressive disorder (MDD) using machine learning. The support vector machine method was applied to 2-channel EEG signals from the frontal lobes (Fp1 and Fp2) of 149 participants to classify PD and MDD patients from healthy individuals using non-linear measures as features. We found significantly lower correlation dimension and Lempel-Ziv complexity in PD patients and MDD patients in the left hemisphere compared to healthy subjects at rest. Most importantly, we obtained a 90% accuracy in classifying MDD patients vs. healthy individuals, a 68% accuracy in classifying PD patients vs. controls, and a 59% classification accuracy between PD and MDD patients. In addition to demonstrating classification performance in a simplified setting, the observed differences in EEG complexity between subject groups suggest altered cortical processing present in the frontal lobes of PD patients that can be captured through non-linear measures. Overall, this study suggests that machine learning and non-linear measures using only 2-channel frontal EEGs are useful for aiding the rapid diagnosis of panic disorder and major depressive disorder.

The prevalence of subthreshold psychiatric symptoms and associations with alcohol and substance use disorders: from a nationally representative survey of 36,309 adults

BACKGROUND

Our aim was to describe a broad number of subthreshold psychiatric symptoms (SPS) in a nationally representative population and evaluate associations with substance use. SPS describe groups of symptoms with significant pathology, but that do not quite meet full psychiatric diagnostic criteria. They have been associated with significant impairment and cost.

METHODS

The National Epidemiologic Survey on Alcohol and Related Conditions-III was a multistage, weighted, cross-sectional survey completed in the United States in 2013 comprising 36,309 noninstitutionalized adults. We report lifetime prevalence rates of 14 SPS related to mood, anxiety, trauma, eating, and personality disorders. We then evaluate associations with lifetime alcohol use disorders (AUD) and all substance use disorders (SUD) using logistic regression and adjusted odds ratios. SPS and psychiatric diagnoses were mutually exclusive (could not co-occur).

RESULTS

Lifetime prevalence of having at least one of 14 SPS was 57% compared with 37% for the related psychiatric disorders. This was similar for males and females, in contrast to psychiatric disorders in which prevalence was 42% in females and 31% in males. Otherwise, overall SPS and disorders had similar prevalence patterns across sociodemographic characteristics. Subthreshold personality symptoms had the highest prevalence rates (schizotypal 21.3%, antisocial 18.3%, and borderline 17.6%), followed by posttraumatic stress (13.1%). Subthreshold bipolar and depression had lifetime prevalence rates of 2.7 and 8.5%, respectively. Prevalence rates of subthreshold anxiety symptoms ranged from 2.2% (agoraphobia) to 9.8% (specific phobia). Subthreshold eating disorder related symptoms had the lowest prevalence rates (anorexia 1.5% and bulimia 1.7%). Half (seven) of the SPS had significantly increased odds of lifetime AUD. This number increased to 12 for all SUD. Subthreshold antisocial personality symptoms had the highest odds of AUD (2.2; 95% CI 2.00-2.37) and SUD (3.5; 95% CI 3.22-3.81).

CONCLUSIONS

We found high lifetime SPS prevalence rates and significant associations with AUD and SUD. To our knowledge, this is the first published study evaluating a broad number of SPS. This indicates possible opportunities for early intervention and prevention but requires additional research and development of infrastructure and guidelines to better understand and manage patients who experience SPS.

Subthreshold lifetime depression and anxiety are associated with increased lifetime suicide attempts: A Korean nationwide study

BACKGROUND

Subthreshold depression and anxiety are highly prevalent and known to be associated with functional limitations and future onset of major depression or anxiety disorders. However, studies regarding suicidality at subthreshold levels of depression and anxiety are limited.

METHODS

A total of 17,639 Koreans aged from 18 to 64 responded to the Korean version of the WHO-composite international diagnostic interview (K-CIDI) version 2.1 between 2006 and 2016. Prevalence of subthreshold depression and anxiety, and information on lifetime suicide attempt (SA) were assessed. Multivariable logistic regression was performed to calculate the risk of SA by the level of depression or anxiety.

RESULTS

The risk of lifetime SA increased incrementally according to the level of depression and anxiety. In the subthreshold depression group, individuals with subthreshold anxiety increased the odds about threefold (OR = 3.15, 95% CI 3.12-3.18) and the threshold anxiety disorder group increased the odds about fivefold (OR = 5.33, 95% CI 5.27-5.38) for SA, compared to the group without any level of anxiety. In threshold depressive disorder, the subthreshold anxiety group showed about 1.8-fold higher odds (OR = 1.76, 95% CI 1.75-1.77) and the threshold anxiety disorder group showed threefold higher odds (OR = 2.93, 95% CI 2.92-2.95) for SA compared to the group without any level of anxiety.

CONCLUSIONS

Subthreshold levels of depression and anxiety were prevalent among Koreans and were associated with an increased prevalence of lifetime SA. A detailed assessment of depression and anxiety symptoms according to their level should be performed on a diagnostic continuum to prevent suicide.

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.

The Co-Morbidity between Bipolar and Panic Disorder in Fibromyalgia Syndrome

About half of the patients with fibromyalgia (FM) had a lifetime major depression episode and one third had a panic disorder (PD). Because the co-morbidity between bipolar disorder (BD) and PD marks a specific subtype of BD we aimed to investigate if co-morbid BD/PD (comBD/PD) occurs more frequently than the single disorder in FM patients and evaluate the clinical significance and timing of this co-morbidity. Further, we explored the role of co-morbid subthreshold BD and PD. In 118 patients with FM, lifetime threshold and sub-threshold mood disorders and PD were diagnosed with Diagnostic and Statistical Manual of Mental Disorders-IV-Text Revision (DSM-IV-TR) Clinical Interview. Demographic and clinical variables were compared in co-morbid BD/PD (comBD/PD) and not co-morbid BD/PD (nocomBD/PD) subgroups. The co-morbidity BD/PD was seen in 46.6% of FM patients and in 68.6% when patients with minor bipolar (MinBD) and sub-threshold panic were included. These rates are higher than those of the general population and BD outpatients. There were no statistically significant differences between threshold and sub-threshold comBD/PD and nocom-BD/PD subgroups in demographic and clinical parameters. In the majority of patients (78.2%), the onset of comBD/PD preceded or was contemporary with FM. These findings support the hypothesis that comBD/PD is related to the development of FM in a subgroup of patients.

Assessing panic disorder-specific competencies: evaluation of the Cognitive Therapy Competence Scale for panic disorder

BACKGROUND

Evidence-based treatment for panic disorder consists of disorder-specific cognitive behavioural therapy (CBT) protocols. However, most measures of CBT competence are generic and there is a clear need for disorder-specific assessment measures.

AIMS

To fill this gap, we evaluated the psychometric properties of the Cognitive Therapy Competence Scale (CTCP) for panic disorder.

METHOD

CBT trainees (n = 60) submitted audio recordings of CBT for panic disorder that were scored on a generic competence measure, the Cognitive Therapy Scale - Revised (CTS-R), and the CTCP by markers with experience in CBT practice and evaluation. Trainees also provided pre- to post-treatment clinical outcomes on disorder-specific patient report measures for cases corresponding to their therapy recordings.

RESULTS

The CTCP exhibited strong internal consistency (α = .79-.91) and inter-rater reliability (ICC = .70-.88). The measure demonstrated convergent validity with the CTS-R (r = .40-.54), although investigation into competence classification indicated that the CTCP may be more sensitive at detecting competence for panic disorder-specific CBT skills. Notably, the CTCP demonstrated the first indication of a relationship between therapist competence and clinical outcome for panic disorder (r = .29-.35); no relationship was found for the CTS-R.

CONCLUSIONS

These findings provide initial support for the reliability and validity of the CTCP for assessing therapist competence in CBT for panic disorder and support the use of anxiety disorder-specific competence measures. Further investigation into the psychometric properties of the measure in other therapist cohorts and its relationship with clinical outcomes is recommended.

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.

Manualized single-session behavior treatment with self-help manual for panic disorder with or without agoraphobia

Objective: We examined the clinical feasibility and utility of a single behavior treatment session, with 11 patients with Panic Disorder with or without Agoraphobia (PD+/-AG). Patients used an individualized, exposure based, homework manual, derived from their behavioral analysis. Treatment was implemented in an outpatient behavior treatment unit. Method: Patients presented with moderate to severe anxiety, avoidance behavior, functional impairment and depressive symptoms. Treatment was evaluated with a double-baseline case series/pre-post design with four follow-ups. Results: There was a significant and steady improvement in all self-rated outcome measures and participants were satisfied with the services provided. Nine out of 11 patients (82%) were free of PD+/-AG at 3 months and all patients at 1-year follow-up. The absence of a control group, the small sample and lack of blind assessments, limit the validity of the study. Conclusions: These case studies provide empirical evidence in support of both the feasibility and utility of a single-session behavior treatment (SSBT) plus self-help implemented in a public mental health unit. Further research with a control group is needed to assess the efficacy of the intervention in routine clinical practice.

Effect of high-frequency repetitive transcranial magnetic stimulation (rTMS) in patients with comorbid panic disorder and major depression

OBJECTIVE

To explore the role of dorsolateral prefrontal cortex (DLPFC) stimulation in the treatment of panic disorder with comorbid depression.

METHODS

The present study reports findings from retrospective analysis of 13 treatment-resistant patients diagnosed with comorbid panic disorder and depression, given 20 sessions of high-frequency transcranial magnetic stimulation (rTMS) over left-DLPFC over a period of 1 month.

RESULTS

There was a significant reduction in both the panic and depressive symptom severity, assessed by applying Panic Disorder Severity Scale (PDSS) and Hamilton Depression Rating Scale (HDRS) at baseline and after 20 sessions of rTMS. There was a 38% and 40% reduction of PDSS and HDRS scores, respectively, in the sample. The changes in PDSS and HDRS scores were not significantly correlated (ρ = -0.103, p = 0.737).

CONCLUSIONS

High-frequency rTMS delivered at left-DLPFC may have a potential role in treatment of comorbid panic disorder and depression. Future studies done on a larger sample in a controlled environment are required to establish its role.

Study Protocol for a Randomized Double Blind, Placebo Controlled Trial Exploring the Effectiveness of a Micronutrient Formula in Improving Symptoms of Anxiety and Depression

Background: Anxiety and depression are conferring an increasing burden on society. Although treatments exist for both conditions, side effects, and difficulties accessing treatment prevent many people from receiving adequate assistance. Nutritional approaches have demonstrated some success in treating anxiety and depression. We plan to investigate whether a micronutrient formula, Daily Essential Nutrients, improves symptoms of anxiety and depression compared to a placebo in a community recruited sample. Methods: This will be a randomized, double blind placebo controlled study (RCT). Two hundred adults will be assigned to either a placebo or micronutrient group (placebo or Daily Essential Nutrients (DEN)) in a 1:1 ratio. Baseline data will be collected for 2 weeks, followed by 10 weeks of placebo or micronutrient intervention. Psychometrics will be used to measure progress and participant safety will be monitored weekly. Results: The primary outcome measures will be total scores on three measures of symptom severity at 10 weeks. Linear mixed modelling will be used to measure between group differences and effect sizes will be calculated using pooled mean scores and standard deviations over the course of the trial. Conclusions: If effective, micronutrients could provide an alternative treatment, with fewer barriers and adverse events than currently available treatments.

Two Novel Cognitive Behavioral Therapy-Based Mobile Apps for Agoraphobia: Randomized Controlled Trial

Background

Despite the large body of literature demonstrating the effectiveness of cognitive behavioral treatments for agoraphobia, many patients remain untreated because of various barriers to treatment. Web-based and mobile-based interventions targeting agoraphobia may provide a solution to this problem, but there is a lack of research investigating the efficacy of such interventions.

Objective

The objective of our study was to evaluate for the first time the effectiveness of a self-guided mobile-based intervention primarily targeting agoraphobic symptoms, with respect to a generic mobile app targeting anxiety.

Methods

A Web-based randomized controlled trial (RCT) compared a novel mobile app designed to target agoraphobia (called Agoraphobia Free) with a mobile app designed to help with symptoms of anxiety in general (called Stress Free). Both interventions were based on established cognitive behavioral principles. We recruited participants (N=170) who self-identified as having agoraphobia and assessed them online at baseline, midpoint, and end point (posttreatment) over a period of 12 weeks. The primary outcome was symptom severity measured by the Panic and Agoraphobia Scale.

Results

Both groups had statistically significant improvements in symptom severity over time (difference –5.97, 95% CI –8.49 to –3.44, P<.001 for Agoraphobia Free and –6.35, 95% CI –8.82 to –3.87, P<.001 for Stress Free), but there were no significant between-group differences on the primary outcome (difference 0.38, 95% CI –1.96 to 3.20, P=.64).

Conclusions

This is, to our knowledge, the first RCT to provide evidence that people who identify as having agoraphobia may equally benefit from a diagnosis-specific and a transdiagnostic mobile-based intervention. We also discuss clinical and research implications for the development and dissemination of mobile mental health apps.

Trial Registration

International Standard Randomized Controlled Trial Number (ISRCTN): 98453199; http://www.isrctn.com /ISRCTN98453199 (Archived by WebCite at http://www.webcitation.org/6uR5vsdZw)

A magnetoencephalography investigation of coherence source imaging in panic disorder

Limbic and frontal structures are largely implicated in panic disorder (PD). Decreased coherence imaging values, as determined by magnetoencephalography (MEG), are suggestive of decreased or inefficient communication among these structures. We have previously demonstrated that coherence source imaging (CSI) values could be similar or higher in some PD patients. The purpose of the current investigation was to replicate these finding in a larger sample. Nine strictly diagnosed PD patients and nine age-matched and sex-matched healthy controls were examined. The CSI-MEG values of 26 frontotemporal regions (FTRs) and 28 extra-frontotemporal regions (ex-FTR; Brodmann areas) were determined for each participant. MEG scans were acquired using a 151-channel whole-head biomagnetometer system. Despite the relatively small sample size, CSI values were significantly lower in a number of FTRs in PD patients. In none of the ex-FTRs (i.e. posterior regions) were there differences between panic and control groups. The above data add to the complexity of understanding the nature of the pathophysiology of PD. Our finding of decreased focal coherence imaging values may reflect decreased excitability in these areas. The preliminary finding could be interpreted as an inhibitory process guarding against the spread of activity in closer hyperexcitable areas as seen in epilepsy. The current data provide evidence for dysfunctional communication within the frontotemporal structures. The findings have implications for the understanding of the neural circuitry underlying PD.

Epidemiology and comorbidity of obsessive-compulsive disorder in late adolescence: a cross-sectional study in senior high schools in Greece

OBJECTIVE

The aim of this study was to examine the epidemiology, comorbidity and use of health services of obsessive-compulsive disorder (OCD) and subclinical obsessive-compulsive symptoms in late adolescence.

METHODS

A total of 2427 adolescents attending senior high schools in Greece were selected for a detailed psychiatric interview using the revised clinical interview schedule (CIS-R). Use of alcohol, nicotine and cannabis, and several socio-demographic and socio-economic variables were also assessed.

RESULTS

The prevalence of OCD was 1.39% (95% confidence interval [CI]: 1.05-1.84) while that of subclinical obsessive-compulsive symptoms was 2.77% (2.22-3.45). There was a female preponderance for subclinical symptoms. Financial difficulties of the family was the only socio-demographic variable that was significantly associated with OCD but not with subclinical symptoms. The pattern of comorbidity was similar for both conditions but milder in the subclinical form. About one in three reported use of general health services and one in ten use of psychiatric services.

CONCLUSIONS

OCD and subclinical obsessive-compulsive symptoms were relatively common. Comorbidity with other psychiatric disorders and use of substances was considerable even in subclinical status, but use of specialised health services was small. Clinical and research implications are discussed.

The Neurobiology of Panic: A Chronic Stress Disorder

Panic disorder is an often chronic and impairing human anxiety syndrome, which frequently results in serious psychiatric and medical comorbidities. Although, to date, there have been many advances in the diagnosis and treatment of panic disorder, its pathophysiology still remains to be elucidated. In this review, recent evidence for a neurobiological basis of panic disorder is reviewed with particular attention to risk factors such as genetic vulnerability, chronic stress, and temperament. In addition, neuroimaging data are reviewed which provides support for the concept of panic disorder as a fear network disorder. The potential impact of the National Institute of Mental Health Research Domain Criteria constructs of acute and chronic threats responses and their implications for the neurobiology of panic disorder are also discussed.

Anxiety

Anxiety disorders (separation anxiety disorder, selective mutism, specific phobias, social anxiety disorder, panic disorder, agoraphobia, and generalised anxiety disorder) are common and disabling conditions that mostly begin during childhood, adolescence, and early adulthood. They differ from developmentally normative or stress-induced transient anxiety by being marked (ie, out of proportion to the actual threat present) and persistent, and by impairing daily functioning. Most anxiety disorders affect almost twice as many women as men. They often co-occur with major depression, alcohol and other substance-use disorders, and personality disorders. Differential diagnosis from physical conditions-including thyroid, cardiac, and respiratory disorders, and substance intoxication and withdrawal-is imperative. If untreated, anxiety disorders tend to recur chronically. Psychological treatments, particularly cognitive behavioural therapy, and pharmacological treatments, particularly selective serotonin-reuptake inhibitors and serotonin-noradrenaline-reuptake inhibitors, are effective, and their combination could be more effective than is treatment with either individually. More research is needed to increase access to and to develop personalised treatments.

A feasibility study of the clinical effectiveness and cost-effectiveness of individual cognitive behavioral therapy for panic disorder in a Japanese clinical setting: an uncontrolled pilot study

Background

In Japan, cognitive behavioral therapy (CBT) for panic disorder (PD) is not well established. Therefore, a feasibility study of the clinical effectiveness and cost-effectiveness of CBT for PD in a Japanese clinical setting is urgently required. This was a pilot uncontrolled trial and the intervention consisted of a 16-week CBT program. The primary outcome was Panic Disorder Severity Scale (PDSS) scores. Quality of life was assessed using the EuroQol’s EQ-5D questionnaire. Assessments were conducted at baseline, 8 weeks, and at the end of the study. Fifteen subjects completed outcome measures at all assessment points.

Results

At post-CBT, the mean reduction in PDSS scores from baseline was −6.6 (95 % CI 3.80 to −9.40, p < 0.001) with a Cohen’s d = 1.77 (95 % CI 0.88–2.55). Ten (66.7 %) participants achieved a 40 % or greater reduction in PDSS. By calculating areas under the curve for EQ-5D index changes, we estimated that patients gained a minimum of 0.102 QALYs per 1 year due to the CBT.

Conclusions

This study demonstrated that individual CBT for PD may be useful in Japanese clinical settings but further randomized control trials are needed.

Trial registration: UMIN-CTR UMIN000022693 (retrospectively registered)

Symptoms of generalized anxiety disorder but not panic disorder at age 15 years increase the risk of depression at 18 years in the Avon Longitudinal Study of Parents and Children (ALSPAC) cohort study

BACKGROUND

Generalized anxiety disorder (GAD) and panic disorder (PD) differ in their biology and co-morbidities. We hypothesized that GAD but not PD symptoms at the age of 15 years are associated with depression diagnosis at 18 years.

METHOD

Using longitudinal data from the Avon Longitudinal Study of Parents and Children (ALSPAC) birth cohort we examined relationships of GAD and PD symptoms (measured by the Development and Well-Being Assessment) at 15 years with depression at 18 years (by the Clinical Interview Schedule - Revised) using logistic regression. We excluded adolescents already depressed at 15 years and adjusted for social class, maternal education, birth order, gender, alcohol intake and smoking. We repeated these analyses following multiple imputation for missing data.

RESULTS

In the sample with complete data (n = 2835), high and moderate GAD symptoms in adolescents not depressed at 15 years were associated with increased risk of depression at 18 years both in unadjusted analyses and adjusting for PD symptoms at 15 years and the above potential confounders. The adjusted odds ratio (OR) for depression at 18 years in adolescents with high relative to low GAD scores was 5.2 [95% confidence interval (CI) 3.0-9.1, overall p < 0.0001]. There were no associations between PD symptoms and depression at 18 years in any model (high relative to low PD scores, adjusted OR = 1.3, 95% CI 0.3-4.8, overall p = 0.737). Missing data imputation strengthened the relationship of GAD symptoms with depression (high relative to low GAD scores, OR = 6.2, 95% CI 3.9-9.9) but those for PD became weaker.

CONCLUSIONS

Symptoms of GAD but not PD at 15 years are associated with depression at 18 years. Clinicians should be aware that adolescents with GAD symptoms may develop depression.

The prevalence and burden of subthreshold generalized anxiety disorder: a systematic review

BACKGROUND

To review the prevalence and impact of generalized anxiety disorder (GAD) below the diagnostic threshold and explore its treatment needs in times of scarce healthcare resources.

METHODS

A systematic literature search was conducted until January 2013 using PUBMED/MEDLINE, PSYCINFO, EMBASE and reference lists to identify epidemiological studies of subthreshold GAD, i.e. GAD symptoms that do not reach the current thresholds of DSM-III-R, DSM-IV or ICD-10. Quality of all included studies was assessed and median prevalences of subthreshold GAD were calculated for different subpopulations.

RESULTS

Inclusion criteria led to 15 high-quality and 3 low-quality epidemiological studies with a total of 48,214 participants being reviewed. Whilst GAD proved to be a common mental health disorder, the prevalence for subthreshold GAD was twice that for the full syndrome. Subthreshold GAD is typically persistent, causing considerably more suffering and impairment in psychosocial and work functioning, benzodiazepine and primary health care use, than in non-anxious individuals. Subthreshold GAD can also increase the risk of onset and worsen the course of a range of comorbid mental health, pain and somatic disorders; further increasing costs. Results are robust against bias due to low study quality.

CONCLUSIONS

Subthreshold GAD is a common, recurrent and impairing disease with verifiable morbidity that claims significant healthcare resources. As such, it should receive additional research and clinical attention.

Trajectories of functioning after remission from anxiety disorders: 2-year course and outcome predictors

BACKGROUND

Anxiety disorders are associated with substantial functional limitations but the course of functioning following symptom remission remains largely unknown.

METHOD

Using data from the Netherlands Study of Depression and Anxiety (NESDA), we examined the 2-year trajectories of functioning in participants with chronic (n = 586) or remitting anxiety disorders (n = 385) and in healthy controls (n = 585). In participants with remitting anxiety disorders, we identified predictors of functioning from among sociodemographic, clinical and vulnerability variables. Data were analysed using linear mixed models (LMMs). Functioning was assessed with the World Health Organization Disability Assessment Schedule II (WHO DAS II).

RESULTS

At baseline, participants with remitting anxiety disorders functioned significantly better than those with chronic anxiety disorders, but significantly worse than controls. In both anxiety disorder groups, most impairment was reported in social functioning, occupational functioning and cognition. During the follow-up, functioning improved in both groups, probably due to treatments received. Participants who achieved symptom remission experienced moderate improvements in social functioning and cognition but not in occupational functioning. Of those who remitted, 45.8% reported functioning scores similar to healthy controls whereas 28.5% still functioned at the level of those with chronic anxiety disorders. Worse functioning was predicted by severe anxiety disorders, use of psychological treatment, co-morbid depressive disorders and maladaptive personality traits.

CONCLUSIONS

In anxiety disorders, symptom remission is accompanied by improvements in functioning but significant functional impairments may persist because of co-morbid disorders, lower functioning prior to the onset of the anxiety disorder or residual subthreshold anxiety symptoms.

Abnormal coherence imaging in panic disorder: a magnetoencephalography investigation

Increased coherence imaging values, as determined by magnetoencephalography, are indicative of increased neural excitability. The purpose of this investigation was to examine coherence imaging values in patients suffering from panic disorder (PD). We also ascertained whether regions with increased coherence had higher representation in the limbic frontotemporal regions (LFTRs). The highest coherence imaging values and their locations, among 54 Brodmann areas, were determined in six PD patients and six age-matched healthy controls. Magnetoencephalography scans were acquired using 148 magnetometer channels and 32 simultaneous EEG channels. Despite the small sample size, coherence imaging values were significantly higher in PD patients. Brain regions with increased coherence were significantly more in areas typically associated with LFTRs in PD patients when compared with controls. The above data suggest that coherence values may be increased in LFTRs of patients with PD. Recent advances in epilepsy research suggest that increased coherence may reflect increased excitability in these brain regions. On the basis of the data provided here as well as in the available literature, we propose that additional research examining coherence values in LFTRs of PD patients could inform the choice of medication in this patient population, with increased coherence (i.e. increased excitability) being a biomarker for favorable responses to medications that limit excitatory transmission, such as benzodiazepines or antiseizure drugs.

Hippocampal hyperexcitability underlies enhanced fear memories in TgNTRK3, a panic disorder mouse model

Panic attacks are a hallmark in panic disorder (PAND). During the panic attack, a strong association with the surrounding context is established suggesting that the hippocampus may be critically involved in the pathophysiology of PAND, given its role in contextual processing. We previously showed that variation in the expression of the neurotrophin tyrosine kinase receptor type 3 (NTRK3) in both PAND patients and a transgenic mouse model (TgNTRK3) may have a role in PAND pathophysiology. Our study examines hippocampal function and activation of the brain fear network in TgNTRK3 mice. TgNTRK3 mice showed increased fear memories accompanied by impaired extinction, congruent with an altered activation pattern of the amygdala-hippocampus-medial prefrontal cortex fear circuit. Moreover, TgNTRK3 mice also showed an unbalanced excitation-to-inhibition ratio in the hippocampal cornu ammonis 3 (CA3)-CA1 subcircuit toward hyperexcitability. The resulting hippocampal hyperexcitability underlies the enhanced fear memories, as supported by the efficacy of tiagabine, a GABA reuptake inhibitor, to rescue fear response. The fearful phenotype appears to be the result of hippocampal hyperexcitability and aberrant fear circuit activation. We conclude that NTRK3 plays a role in PAND by regulating hippocampus-dependent fear memories.

Health-seeking behavior, alternative medicine, and quality of life in Taiwanese panic disorder patients

OBJECTIVE

Panic disorder (PD) is an anxiety disorder characterized by spontaneous and unexpected panic attacks of varying frequency. Clinically manifest PD is widespread among the general population in developed countries worldwide. This study is aimed to identify factors influencing Taiwanese patients' decision to seek psychiatric help and to assess relationships between patients' health-seeking behaviors and quality of life (QOL).

METHODS

One hundred patients from the outpatient psychiatric clinic of a university hospital in Taiwan were evaluated for PD.

RESULTS

Delayed diagnosis of panic disorder, high comorbidity with other mental and physical disorders, and high utilization of health care services were identified. Thirty-three percent of PD patients sought alternative therapies, delaying their seeking psychiatric care.

CONCLUSIONS

More PD patients in Taiwan seek care from family practitioners and alternative and complementary medicine than from psychiatrists. Taiwanese patients with PD who seek psychiatric consultation more than one year after disease onset have lower QOL and lower physical health scores.

Longitudinal course of panic disorder with and without agoraphobia using the National Epidemiologic Survey on Alcohol and Related Conditions (NESARC)

Few naturalistic, longitudinal studies of panic disorder with and without agoraphobia (PD/PDA) exist, limiting our knowledge of the temporal rates of incidence, relapse, and chronicity, or the factors that predict category transition. Data from the National Epidemiologic Survey on Alcohol and Related Conditions (NESARC) wave 1 (n=43,093) and wave 2 (n=34,653) were utilized to determine transitional rates, and predictors of category transitions, over a 3-year period. Analyses revealed very high 3-year remission rates for PD and PDA (75% and 67%, respectively), although relapse also was relatively frequent (PD=12%; PDA=21%). Logistic regression revealed previous history of panic attacks, generalized anxiety disorder/major depression (GAD/MDD), nicotine dependence, female sex, younger age, and major financial crises to be reliable predictors of incidence and relapse. The direction and magnitude of association of many predictor variables were similar for PD and PDA, with notable exceptions for social anxiety and romantic relationship factors. Clinicians should be aware of the relapsing-remitting nature of PD and PDA and, thus, take caution to not reduce or eliminate effective treatments prematurely. Similarly, the current study suggests clinicians pay particular attention to concurrent factors relevant to relapse in PD/PDA that may also be clinically addressed (e.g., co-morbid MDD/GAD and nicotine dependence).

Assessing DSM-IV symptoms of panic attack in the general population: an item response analysis

BACKGROUND

Unexpected panic attacks may represent a non-specific risk factor for future depression and anxiety disorders. The examination of panic symptoms and associated latent severity levels may lead to improvements in the identification, prevention, and treatment of panic attacks and subsequent psychopathology for 'at risk' individuals in the general population.

METHODS

The current study utilised item response theory to assess the DSM-IV symptoms of panic in relation to the latent severity level of the panic attack construct in a sample of 5913 respondents from the National Epidemiologic Survey on Alcohol and Related conditions. Additionally, differential item functioning (DIF) was assessed to determine if each symptom of panic targets the same level of latent severity between different sociodemographic groups (male/female, young/old).

RESULTS

Symptoms indexing 'choking', 'fear of dying', and 'tingling/numbness' are some of the more severe symptoms of panic whilst 'heart racing', 'short of breath', 'tremble/shake', 'dizzy/faint', and 'perspire' are some of the least severe symptoms. Significant levels of DIF were detected in the 'perspire' symptom between males and females and the 'fear of dying' symptom between young and old respondents.

LIMITATIONS

The current study was limited to examining cross-sectional data from respondents who had experienced at least one panic attack across their lifetime.

CONCLUSIONS

The findings of the current study provide additional information regarding panic symptoms in the general population that may enable researchers and clinicians to further refine the detection of 'at-risk' individuals who experience threshold and sub-threshold levels of panic.

EEG microstate analysis in drug-naive patients with panic disorder

Patients with panic disorder (PD) have a bias to respond to normal stimuli in a fearful way. This may be due to the preactivation of fear-associated networks prior to stimulus perception. Based on EEG, we investigated the difference between patients with PD and normal controls in resting state activity using features of transiently stable brain states (microstates). EEGs from 18 drug-naive patients and 18 healthy controls were analyzed. Microstate analysis showed that one class of microstates (with a right-anterior to left-posterior orientation of the mapped field) displayed longer durations and covered more of the total time in the patients than controls. Another microstate class (with a symmetric, anterior-posterior orientation) was observed less frequently in the patients compared to controls. The observation that selected microstate classes differ between patients with PD and controls suggests that specific brain functions are altered already during resting condition. The altered resting state may be the starting point of the observed dysfunctional processing of phobic stimuli.