Characterizing generalized anxiety: temporal and symptomatic thresholds

Using Alternative Definitions of Controls to Increase Statistical Power in GWAS

Genome-wide association studies (GWAS) are often underpowered due to small effect sizes of common single nucleotide polymorphisms (SNPs) on phenotypes and extreme multiple testing thresholds. The most common approach for increasing statistical power is to increase sample size. We propose an alternative strategy of redefining case-control outcomes into ordinal case-subthreshold-asymptomatic variables. While maintaining the clinical case threshold, we subdivide controls into two groups: individuals who are symptomatic but do not meet the clinical criteria for diagnosis (subthreshold) and individuals who are effectively asymptomatic. We conducted a simulation study to examine the impact of effect size, minor allele frequency, population prevalence, and the prevalence of the subthreshold group on statistical power to detect genetic associations in three scenarios: a standard case-control, an ordinal, and a case-asymptomatic control analysis. Our results suggest the ordinal model consistently provides the greatest statistical power while the case-control model the least. Power in the case-asymptomatic control model reflects the case-control or ordinal model depending on the population prevalence and size of the subthreshold category. We then analyzed a major depression phenotype from the UK Biobank to corroborate our simulation results. Overall, the ordinal model improves statistical power in GWAS consistent with increasing the sample size by approximately 10%.

Using Alternative Definitions of Controls to Increase Statistical Power in GWAS

Genome-wide association studies (GWAS) are underpowered due to small effect sizes of single nucleotide polymorphisms (SNPs) on phenotypes and extreme multiple testing thresholds. The most common approach for increasing statistical power is to increase sample size. We propose an alternative strategy of redefining case-control outcomes into ordinal case-subthreshold-asymptomatic variables. While maintaining the clinical case threshold, we subdivide controls into two groups: individuals who are symptomatic but do not meet the clinical criteria for diagnosis (subthreshold) and individuals who are effectively asymptomatic. We conducted a simulation study to examine the impact of effect size, minor allele frequency, population prevalence, and the prevalence of the subthreshold group on statistical power to detect genetic associations in three scenarios: a standard case-control, an ordinal, and a case-asymptomatic control analysis. Our results suggest the ordinal model consistently provides the most statistical power while the case-control model the least. Power in the case-asymptomatic control model reflects the case-control or ordinal model depending on the population prevalence and size of the subthreshold category. We then analyzed a major depression phenotype from the UK Biobank to corroborate our simulation results. Overall, the ordinal model improves statistical power in GWAS consistent with increasing the sample size by approximately 10%.

Subsyndromal generalised anxiety disorder: operationalisation and epidemiology - a systematic literature survey

The diagnosis of anxiety disorders, like other psychiatric disorders also, is operationalised since the introduction of diagnostic manuals. The diagnostic criteria of Generalised Anxiety Disorder (GAD) have been tightened in the last decades. This leads to the exclusion of patients with a high level of anxiety, but not fulfilling certain of the GAD-criteria, from effective treatment. Such so-called subsyndromal, subthreshold or subclinical GAD-states, however, often exhibit a comparable burden of disease like the full syndromal disorder and often tend to develop into the full syndromal disorder. The purpose of this review is - beside systematically reporting the papers found in respective data bases from 2013 onwards - to summarise the relevant data regarding definitions, epidemiology and consequences of subsyndromal anxiety states in order to give a comprehensive review.

Specific phobias

Anxiety disorders are among the most prevalent mental disorders, but the subcategory of specific phobias has not been well studied. Phobias involve both fear and avoidance. For people who have specific phobias, avoidance can reduce the constancy and severity of distress and impairment. However, these phobias are important because of their early onset and strong persistence over time. Studies indicate that the lifetime prevalence of specific phobias around the world ranges from 3% to 15%, with fears and phobias concerning heights and animals being the most common. The developmental course of phobias, which progress from fear to avoidance and then to diagnosis, suggests the possibility that interrupting the course of phobias could reduce their prevalence. Although specific phobias often begin in childhood, their incidence peaks during midlife and old age. Phobias persist for several years or even decades in 10-30% of cases, and are strongly predictive of onset of other anxiety, mood, and substance-use disorders. Their high comorbidity with other mental disorders, especially after onset of the phobia, suggests that early treatment of phobias could also alter the risk of other disorders. Exposure therapy remains the treatment of choice, although this approach might be less effective in the long term than previously believed. This Review discusses the literature regarding the prevalence, incidence, course, risk factors, and treatment of specific phobias, and presents epidemiological data from several population-based surveys.

Psychiatric symptoms after acute respiratory distress syndrome: a 5-year longitudinal study

PURPOSE

We aimed to characterize anxiety, depression, and posttraumatic stress disorder (PTSD) symptoms over 5-year follow-up after acute respiratory distress syndrome (ARDS) and determine risk factors for prolonged psychiatric morbidity.

METHODS

This prospective cohort study enrolled patients from 13 medical and surgical intensive care units in four hospitals, with follow-up at 3, 6, 12, 24, 36, 48, and 60 months post-ARDS. Trained research staff administered the Hospital Anxiety and Depression Scale (HADS) (scores ≥ 8 on anxiety and depression subscales indicating substantial symptoms) and the Impact of Event Scale-Revised (IES-R, scores ≥ 1.6 indicating substantial PTSD symptoms) at each follow-up visit.

RESULTS

Of 196 consenting survivors, 186 (95%) completed HADS and IES-R assessments; 96 (52%) had any continuous or recurring (prolonged) symptoms, and 71 (38%), 59 (32%), and 43 (23%) had prolonged anxiety, depression, and PTSD symptoms, respectively (median total durations 33-39 months, 71-100% of observed follow-up time). Prolonged psychiatric symptoms tended to co-occur across domains; the most common morbidity pattern involved substantial symptoms in all three domains. Worse pre-ARDS mental health, including prior depression and psychological distress in the period immediately preceding ARDS, was strongly associated with prolonged post-ARDS psychiatric morbidity across symptom domains.

CONCLUSIONS

Clinically significant and long-lasting symptoms of anxiety, depression, and PTSD are common in the first 5 years after ARDS. In-hospital screening of psychiatric history, including recent anxiety and depression symptoms, may be useful for long-term mental health treatment planning after ARDS.

Integrating iCBT for generalized anxiety disorder into routine clinical care: Treatment effects across the adult lifespan

The burden attributable to late-life Generalized Anxiety Disorder (GAD) is set to increase alongside the ageing population. Yet, the psychogeriatric workforce is limited in size and few studies have focused on the treatment of GAD among older patients. Internet-delivered cognitive behavioral therapy (iCBT) could be integrated into existing infrastructure and scale the psychogeriatric workforce, if shown to be effective across the adult lifespan. This study examined age-related differences in presentation, adherence and effects of iCBT for GAD among patients in routine clinical care (N=942; 18-29years (n=267); 30-39years (n=260); 40-49years (n=180); 50-59years (n=124); and 60+ years (n=111)). Compared to younger patients, older patients were less likely to present with probable GAD and MDD diagnoses (<60years vs. 60+ years) and more likely to complete treatment (<50years vs. 50+ years). iCBT produced moderate to large effect size reductions in symptom severity, distress and impairment independent of age. iCBT is therefore an effective treatment for GAD across the adult lifespan, which can be delivered in routine clinical care. Continuing to integrate iCBT into existing services has the potential to improve the capacity of the existing workforce to manage those seeking help for GAD particularly as the population ages.

Classification models for subthreshold generalized anxiety disorder in a college population: Implications for prevention

Generalized anxiety disorder (GAD) is one of the most common psychiatric disorders on college campuses and often goes unidentified and untreated. We propose a combined prevention and treatment model composed of evidence-based self-help (SH) and guided self-help (GSH) interventions to address this issue. To inform the development of this stepped-care model of intervention delivery, we evaluated results from a population-based anxiety screening of college students. A primary model was developed to illustrate how increasing levels of symptomatology could be linked to prevention/treatment interventions. We used screening data to propose four models of classification for populations at risk for GAD. We then explored the cost considerations of implementing this prevention/treatment stepped-care model. Among 2489 college students (mean age 19.1 years; 67% female), 8.0% (198/2489) met DSM-5 clinical criteria for GAD, in line with expected clinical rates for this population. At-risk Model 1 (subthreshold, but considerable symptoms of anxiety) identified 13.7% of students as potentially at risk for developing GAD. Model 2 (subthreshold, but high GAD symptom severity) identified 13.7%. Model 3 (subthreshold, but symptoms were distressing) identified 12.3%. Model 4 (subthreshold, but considerable worry) identified 17.4%. There was little overlap among these models, with a combined at-risk population of 39.4%. The efficiency of these models in identifying those truly at risk and the cost and efficacy of preventive interventions will determine if prevention is viable. Using Model 1 data and conservative cost estimates, we found that a preventive intervention effect size of even 0.2 could make a prevention/treatment model more cost-effective than existing models of "wait-and-treat."

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.

Structure of the DSM-5 generalized anxiety disorder criteria among a large community sample of worriers

BACKGROUND

There is growing empirical and clinical consensus that many psychiatric disorders are continuous in nature. The DSM-5 however makes a categorical distinction between subthreshold and threshold cases of generalized anxiety disorder (GAD). This study tested the a priori assumption that the DSM-5 criteria identify a break in psychopathology between subthreshold and threshold cases of GAD.

METHODS

Respondents of the 2007 National Survey of Mental Health and Well Being who self-identified as worriers were selected for analyses (n=1738). The GAD criteria were assessed using the World Mental Health version of the Composite International Diagnostic Interview. Item response, latent class and factor mixture models were estimated to assess the structure of the GAD criteria.

RESULTS

The relative fit of the latent variable models suggested that a single continuous factor explains the way that worriers endorse the GAD criteria. However, the similar psychometric properties of the GAD criteria suggested that the GAD criteria impose a relatively finite threshold over this dimension of severity.

LIMITATIONS

Although these structural analyses did not identify a break in psychopathology between subthreshold and threshold cases of GAD based on the way that respondents endorsed the DSM-5 criteria, it is possible that structural analyses of risk factors and other clinical correlates of GAD may identify such a break in the future.

CONCLUSIONS

These data suggest that the DSM-5 GAD criteria lend themselves to making both categorical decisions about cases as well as being indices of a continuum of severity.

Generalized anxiety disorder: between neglect and an epidemic

This article reviews the main issues associated with the concept and the diagnosis of generalized anxiety disorder (GAD) and examines the proposed DSM-5 diagnostic criteria for GAD. The lack of specific features, which is the primary issue for GAD, will not be addressed in DSM-5. The hallmark of the condition will remain pathological worry, although it also characterizes other disorders. Likewise, the proposed behavioral diagnostic criteria lack specificity for GAD, and it is not clear how these will be assessed. The proposed changes will lower the diagnostic threshold for GAD in DSM-5. Although this will not necessarily lead to a better recognition of GAD and an improvement in the perception of its relevance and clinical utility, many currently subthreshold cases will qualify for this diagnosis. The likely inclusion of many such "false-positives" will result in an artificial increase in the prevalence of GAD and will have further negative consequences.

The diagnostic threshold of generalized anxiety disorder in the community: a developmental perspective

Discussion surrounds the question as to whether criteria for generalized anxiety disorder (GAD) should change, particularly in youth. This study examines the effects of possible criteria changes on GAD prevalence and clinical correlates. DSM-IV GAD was assessed using the M-CIDI in a community sample of adolescents and young adults. Diagnostic thresholds were modified in two age spans (9-20 and 21-34 years) using a person-by-year data file (N = 38,534 cases). Relaxing the duration or excessiveness criteria led to the most pronounced changes in GAD prevalence, while relaxing frequency, uncontrollability, or associated-symptom criteria had smaller effects. A lower duration requirement increased rates more in older than younger age spans. Opposite effects occurred for changes in associated-symptoms or clinical-significance criteria. Broader GAD definitions identified cases in both age spans that appeared mostly milder than DSM-IV cases but that still differed from non-GAD cases in various clinical factors and validators. Developmental aspects require stronger consideration in future diagnostic systems.

Generalized anxiety disorder: clinical presentation, diagnostic features, and guidelines for clinical practice

Generalized anxiety disorder (GAD) is a prevalent and disabling disorder characterised by persistent worrying, anxiety symptoms, and tension. General practitioners and mental healthcare professionals frequently misdiagnose the presenting symptoms. This article addresses the clinical presentation of GAD and provides guidelines for discriminating GAD from other disorders, based on theoretical considerations and clinical experience. Debate relating to the validity of the definition of GAD is discussed, and suggestions are made for improving the criteria for GAD, which may guide future versions of classification systems such as the Diagnostic and Statistical Manual.

Anxiety disorders diagnosis: some history and controversies

Treatment of and research on anxiety disorders depends on the adequate conceptualization and measurement of these conditions. We review the history of the nosology of anxiety disorders and note that divisions of "neurosis" have inadvertently taken attention away from what is shared among conditions now classified separately. We note the changes in the definition of agoraphobia over time and the striking differences between DSM-IV and ICD-10 definitions. We mention ongoing controversies in the diagnoses of posttraumatic stress disorder, acute stress disorder, and generalized anxiety disorder. Finally, we discuss controversies surrounding the proper placement of obsessive-compulsive disorder and putatively related conditions in future diagnostic classifications. We hope that reviewing controversial aspects of diagnosis is useful to clinicians and researchers interested in the neurobiology of anxiety disorders.

Subjective distress predicts treatment seeking for depression, bipolar, anxiety, panic, neurasthenia and insomnia severity spectra

OBJECTIVE

To examine correlates of mental health treatment seeking such as gender, diagnosis, impairment, distress and mastery.

METHOD

Longitudinal epidemiological data from the Zurich Study of common psychiatric syndromes, including unipolar and bipolar depression, panic, anxiety, neurasthenia and insomnia, were utilized. In longitudinal Generalized Estimating Equations, treatment seeking was regressed on measures of subjective distress and impairment, childhood family problems, mastery and number of comorbid diagnoses.

RESULTS

Approximately half of all treated participants across all six syndromes suffered from subthreshold disorders. Meeting full or subthreshold diagnostic criteria was associated with treatment seeking for insomnia. Being female was associated with treatment seeking for depression. The only variable highly and consistently associated with treatment seeking, across all syndromes, was subjective distress. Treated participants reported high levels of distress, work and social impairment in both diagnostic and subthreshold groups.

CONCLUSION

Subjective distress may be a better indicator of treatment seeking than symptom count.

Generalized worry disorder: a review of DSM-IV generalized anxiety disorder and options for DSM-V

BACKGROUND

Generalized anxiety disorder (GAD) has undergone a series of substantial classificatory changes since its first inclusion in DSM-III. The majority of these revisions have been in response to its poor inter-rater reliability and concerns that it may lack diagnostic validity. This article provides options for the revision of the DSM-IV GAD criteria for DSM-V.

METHOD

First, searches were conducted to identify the evidence that previous DSM Work Groups relied upon when revising the DSM-III-R GAD and the overanxious disorder classifications. Second, the literature pertaining to the DSM-IV criteria for GAD was examined.

CONCLUSIONS

The review presents a number of options to be considered for DSM-V. One option is for GAD to be re-labeled in DSM-V as generalized worry disorder. This would reflect its hallmark feature. Proposed revisions would result in a disorder that is characterized by excessive anxiety and worry generalized to a number of events or activities for 3 months or more. Worry acts as a cognitive coping strategy that manifests in avoidant behaviors. The reliability and validity of the proposed changes could be investigated in DSM-V validity tests and field trials.

Generalized anxiety disorder with and without excessive worry in Hong Kong

BACKGROUND

Two previous U.S. studies found that although generalized anxiety disorder (GAD) without self-perceived excessive worry was milder than GAD with excessive worry, its persistence, impairment, and risk for subsequent onset of other mental disorders were still substantial. This study examined the implications of relaxing the "excessiveness" criterion on the prevalence and socio-demographic profile of GAD in a Chinese population sample by considering both self and others' perception of excessive worry.

METHOD

2,005 respondents aged 15-65 years participated in a structured telephone interview that covered socio-demographic profile, 12-month DSM-IV diagnosis of GAD, core depressive symptoms, longest duration of worry episode, number of domains of worry, impairment measured by the Sheehan Disability Scale, and treatment-seeking. Excessive worry was assessed from the perception of both respondents and others as reported by respondents.

RESULT

The 12-month prevalence of GAD increased from 3.4 to 4% when the excessiveness requirement was relaxed. Excessive GAD and nonexcessive GAD had similar socio-demographic, symptom, chronicity, impairment, depressive symptom, and treatment-seeking profiles.

CONCLUSION

GAD without excessive worry was less common than GAD with excessive worry but was likely to be a valid nosological entity. Future iterations of the DSM-IV should clarify whether excessive worry should be retained and, if so, how individuals who only reported excessive worries perceived by others should be optimally assessed.

Implications of modifying the duration requirement of generalized anxiety disorder in developed and developing countries

BACKGROUND

A number of western studies have suggested that the 6-month duration requirement of generalized anxiety disorder (GAD) does not represent a critical threshold in terms of onset, course, or risk factors of the disorder. No study has examined the consequences of modifying the duration requirement across a wide range of correlates in both developed and developing countries.

METHOD

Population surveys were carried out in seven developing and 10 developed countries using the WHO Composite International Diagnostic Interview (total sample=85,052). Prevalence and correlates of GAD were compared across mutually exclusive GAD subgroups defined by different minimum duration criteria.

RESULTS

Lifetime prevalence estimates for GAD lasting 1 month, 3 months, 6 months and 12 months were 7.5%, 5.2%, 4.1% and 3.0% for developed countries and 2.7%, 1.8%, 1.5% and 1.2% for developing countries, respectively. There was little difference between GAD of 6 months' duration and GAD of shorter durations (1-2 months, 3-5 months) in age of onset, symptom severity or persistence, co-morbidity or impairment. GAD lasting >or=12 months was the most severe, persistently symptomatic and impaired subgroup.

CONCLUSIONS

In both developed and developing countries, the clinical profile of GAD is similar regardless of duration. The DSM-IV 6-month duration criterion excludes a large number of individuals who present with shorter generalized anxiety episodes which may be recurrent, impairing and contributory to treatment-seeking. Future iterations of the DSM and ICD should consider modifying the 6-month duration criterion so as to better capture the diversity of clinically salient anxiety presentations.

Generalized anxiety disorder in China: prevalence, sociodemographic correlates, comorbidity, and suicide attempts

PURPOSE

This study aims to determine the 12-month and lifetime prevalence of generalized anxiety disorder (GAD) and its sociodemographic correlates.

DESIGN AND METHODS

A total of 5,926 subjects were randomly selected and interviewed.

FINDINGS

The overall 12-month and lifetime prevalence of GAD was 0.8%, and 1.2%, respectively. Being older than 25 years and female, lower education level, unemployed status, and lower (<RMB500/month) or higher (>RMB2000/month) monthly income were associated with increased risk of GAD.

PRACTICE IMPLICATIONS

The low percentage of subjects treated for GAD indicates a major public health problem that should be addressed.

The generalized anxiety spectrum: prevalence, onset, course and outcome

BACKGROUND

Generalized anxiety disorder (GAD) is generally considered to be a chronic condition, waxing and waning in severity; however prospective investigation of the course of GAD in community samples is lacking. This study seeks to fill that gap, by identifying the whole spectrum of generalized anxiety syndromes, sub-typing them according to their duration and frequency of occurrence, and evaluating their long-term course and outcome in the community.

METHOD

The prospective Zurich Study assessed psychiatric and somatic syndromes in a community sample of young adults (N = 591) (aged 20 years at first interview) by six interviews over a period of 20 years (1979-1999). GAD syndromes were defined by DSM-III symptom criteria without applying any exclusion criteria. A spectrum of generalized anxiety was defined by duration: 6 months (DSM-IV), 1 month (DSM-III), < or = 2 weeks (with weekly occurrence over one year), and anxiety symptoms. From 1978 (screening) to 1999 the annual presence of symptoms and treatment was assessed. Persistence of anxiety was defined by the almost daily presence of symptoms over the previous 12 months.

RESULTS

The annual incidence of DSM-III GAD increased considerably between the ages of 20 and 40. The average age of onset of symptoms was 15.6 years; in 75% of cases it occurred before the age of 20. 75 of 105 DSM-III GAD cases had at least one follow-up. At their individual last follow-up, 12 of those 75 subjects (16%) were re-diagnosed as having GAD, 22 (29%) manifested subthreshold syndromes or anxiety symptoms, while 39 cases, the majority, (52%) were symptom-free; 5 of the 12 re-diagnosed GAD cases were persistent (corresponding to 7% of all 75 initial GAD cases). In their twenties they were treated at some time in 6% of all years, but in their thirties this figure rose to 12%. At their individual last follow-up 26% of 6-month GAD subjects and 22% of 1-month GAD subjects were still being treated. Treated vs. non-treated subjects did not differ in terms of gender but did differ in severity, persistence and in comorbidity with bipolar-II disorder, social phobia, obsessive-compulsive syndromes and substance-use disorders.

LIMITATIONS

Results are based on a relatively small sample and cannot be generalized to adults aged over 40 years.

CONCLUSIONS

The course of DSM-III-defined GAD may not be chronic, as previously suggested, but mainly recurrent with intervening symptom-free periods of recovery in about half of cases. Over a period of 20 years there was more improvement than progression within the anxiety spectrum.

Pathological worry, anxiety disorders and the impact of co-occurrence with depressive and other anxiety disorders

The Penn State Worry Questionnaire (PSWQ) was administered to 123 outpatients with principal diagnoses of generalized anxiety disorder (GAD), social anxiety disorder (SAD), panic disorder with agoraphobia, and panic disorder without agoraphobia (PD) to examine the specificity of pathological worry for GAD. The mean PSWQ scores in patients with GAD and SAD were significantly higher than the mean PSWQ scores in patients with PD, while not differing significantly in the subgroups without any co-occurring depressive or anxiety disorders. Patients with any co-occurring depressive or anxiety disorder scored significantly higher on the PSWQ. In a logistic regression analysis, high PSWQ scores independently predicted only GAD and SAD diagnoses. The study suggests that pathological worry is specific not only for GAD, and indicates that a significant relationship exists between pathological worry, GAD and SAD, and that depressive and anxiety disorders co-occurrence increases levels of pathological worry in patients with anxiety disorders.

Broadening the definition of generalized anxiety disorder: effects on prevalence and associations with other disorders in the National Comorbidity Survey Replication

Concerns have been raised that the DSM-IV requirements of 6-month duration, excessive worry, and three associated symptoms exclude a substantial number of people with clinically significant anxiety from a diagnosis of generalized anxiety disorder (GAD). We examined the implications of relaxing these three criteria for the estimated prevalence and predictive validity of GAD using nationally representative data from the US National Comorbidity Survey Replication. Relaxing all three criteria more than doubles the estimated prevalence of GAD. Broadly defined GAD significantly predicts the subsequent first onset of a wide range of temporally secondary disorders. The odds of secondary disorders are somewhat smaller for broadly defined than DSM-IV GAD, though few of these differences are statistically significant. Results suggest that subthreshold manifestations of GAD are significantly related to elevated risk of subsequent psychopathology. Further research is needed to determine whether broadening the current diagnostic criteria results in a more valid characterization of GAD.

Should excessive worry be required for a diagnosis of generalized anxiety disorder? Results from the US National Comorbidity Survey Replication

BACKGROUND

Excessive worry is required by DSM-IV, but not ICD-10, for a diagnosis of generalized anxiety disorder (GAD). No large-scale epidemiological study has ever examined the implications of this requirement for estimates of prevalence, severity, or correlates of GAD.

METHOD

Data were analyzed from the US National Comorbidity Survey Replication, a nationally representative, face-to-face survey of adults in the USA household population that was fielded in 2001-2003. DSM-IV GAD was assessed with Version 3.0 of the WHO Composite International Diagnostic Interview. Non-excessive worriers meeting all other DSM-IV criteria for GAD were compared with respondents who met full GAD criteria as well as with other survey respondents to consider the implications of removing the excessiveness requirement.

RESULTS

The estimated lifetime prevalence of GAD increases by approximately 40% when the excessiveness requirement is removed. Excessive GAD begins earlier in life, has a more chronic course, and is associated with greater symptom severity and psychiatric co-morbidity than non-excessive GAD. However, non-excessive cases nonetheless evidence substantial persistence and impairment of GAD, high rates of treatment-seeking, and significantly elevated co-morbidity compared with respondents without GAD. Non-excessive cases also have sociodemographic characteristics and familial aggregation of GAD comparable to excessive cases.

CONCLUSIONS

Individuals who meet all criteria for GAD other than excessiveness have a somewhat milder presentation than those with excessive worry, yet resemble excessive worriers in a number of important ways. These findings challenge the validity of the excessiveness requirement and highlight the need for further research into the optimal definition of GAD.

Generalized Anxiety Disorder and major depressive disorder comorbidity in the National Survey of Mental Health and Well-Being

We report population data on DSM-IV Generalized Anxiety Disorder (GAD) from the Australian National Survey of Mental Health and Well-Being, obtained from a nationwide household survey of adults using a stratified multistage sampling process. A response rate of 78.1% resulted in 10,641 persons being interviewed. Diagnoses were made using the Composite International Diagnostic Interview. The interview was computerised and conducted by trained lay interviewers. We investigated comorbidity between GAD and major depressive disorder (MDD). The results indicate that sociodemographic correlates of GAD, and associated disablement and service use, are influenced by the presence of a comorbid depressive disorder but cannot be fully explained by the presence of that disorder. In addition, GAD was confirmed as significantly disabling, even as a single disorder. We conclude that the results are consistent with the view that GAD has a significant and independent impact on the burden of mental disorders.

Generalized anxiety disorder: acute and chronic treatment

Clinical and epidemiological data suggest that generalized anxiety disorder (GAD) is a chronic illness causing patients to suffer for many years leading to significant distress in daily life functioning. The literature suggests the several conclusions. GAD is a disorder in need of appropriate treatment and often has a chronic course with comorbid conditions, such as major depression and other anxiety disorders. Benzodiazepines, while effective anxiolytic agents acutely, when prescribed for >4 weeks cause rebound anxiety and following prolonged therapy may lead to withdrawal symptoms. Antidepressants cause significant anxiety relief compared with placebo and for psychosocial treatment cognitive-behavioral therapy is an efficacious psychosocial treatment. Many GAD patients are in need of long-term medication management. Furthermore, there is limited data for patients diagnosed with GAD the treatment outcome with the combination of medication and psychotherapy both acutely and long-term; how to best sequence these treatments; for those patients who do not meet remission criteria what is the ideal approach for augmentation; and for patients with treatment-refractory GAD the empirical evidence is lacking on medication switching and augmentation strategies. Research is needed in the area of developing treatment strategies for patients suffering from treatment-refractory GAD. There is still an urgent need to explore treatment combinations and duration strategies in the management of patients suffering with GAD.

Emotional disorders in primary care

Individuals with emotional disorders are more likely to use primary medical care than specialty mental health services, but these disorders are likely to be undetected or inadequately treated. Recognition of the importance of primary medical care for the treatment of mental disorder has resulted in pressing new research priorities. One set of issues concerns the adequacy of existing nosological systems for conceptualizing emotional disorder in primary care and identifying need for treatment. Another concerns the difficulties translating efficacious treatment into effective strategies that can be integrated into the competing demands of primary medical care. Psychologists have played only a limited role in defining and addressing emerging questions. Irreversible changes in mental health services have created the need for the development of a psychosocial perspective for what would otherwise be defined as narrowly biomedical issues.

A population-based twin study of generalized anxiety disorder in men and women

This study aimed to a) assess whether genetic or environmental effects are of similar magnitude in the etiology of GAD in men and women, and b) investigate whether familial (genetic or common environmental) risk factors are the same in men and women, or whether there are gender-specific effects. We obtained a lifetime history of DSM-IIII-R GAD, via face-to-face and telephone interviews, from 3100 complete male-male, female-female, and male-female twin pairs, ascertained through a population-based registry. Biometrical twin modeling was utilized to estimate the relative contributions of genetic and environmental factors to liability for GAD, allowing for gender-specific effects. The familial aggregation of GAD in this sample was only modest. In the best-fitting models, the heritability of GAD was the same in men and women, estimated at about 15% to 20%, with no effects of gender-specific genes detected.

Overview and clinical presentation of generalized anxiety disorder

1. To distinguish GAD from panic disorder is not difficult if a patient has frequent, spontaneous panic attacks and agoraphobic symptoms, but many patients with GAD have occasional anxiety attacks or panic attacks. Such patients should be considered as having GAD. An even closer overlap probably exists between GAD and social phobia. Patients with clear-cut phobic avoidant behavior may be distinguished easily from patients with GAD, but patients with social anxiety without clear-cut phobic avoidant behavior may overlap with patients with GAD and possibly should be diagnosed as having GAD and not social phobia. The cardinal symptoms of GAD commonly overlap with those of social phobia, particularly if the social phobia is more general and not focused on a phobic situation. For example, free-floating anxiety may cause the hands to perspire and may cause a person to be shy in dealing with people in public, and thus many patients with subthreshold social phobic symptoms have, in the authors' opinion, GAD and not generalized social phobia. The distinction between GAD and obsessive-compulsive disorder, acute stress disorder, and posttraumatic stress disorder should not be difficult by definition. At times, however, it may be difficult to distinguish between adjustment disorder with anxious mood from GAD or anxiety not otherwise specified, particularly if the adjustment disorder occurs in a patient with a high level of neuroticism or trait anxiety or type C personality disorder. Table 2 presents features distinguishing GAD from other psychiatric disorders. 2. Lifetime comorbid diagnoses of other anxiety or depression disorders, not active for 1 year or more and not necessitating treatment during that time period, should not effect a diagnosis of current GAD. On the other hand, if concomitant depressive symptoms are present and if these are subthreshold, a diagnosis of GAD should be made, and if these are full threshold, a diagnosis of MDD should be made. 3. If GAD is primary and if no such current comorbid diagnosis, such as other anxiety disorders or MDD, is present, except for minor depression and dysthymia, or if only subthreshold symptoms of other anxiety disorders are present, GAD should be considered primary and treated as GAD; however, patients with concurrent threshold anxiety or mood disorders should be diagnosed according to the definitions of these disorders in the DSM-IV and ICD-10 and treated as such. 4. Somatization disorders are now classified separately from anxiety disorders. Some of these, particularly undifferentiated somatization disorder, may overlap with GAD and be diagnostically difficult to distinguish. The authors believe that, as long as psychic symptoms of anxiety are present and predominant, patients should be given a primary diagnosis of GAD. 5. Two major shifts in the DSM diagnostic criteria for GAD have markedly redefined the definition of this disorder. One shift involves the duration criterion from 1 to 6 months, and the other, the increased emphasis on worry and secondary psychic [table: see text] symptoms accompanied by the elimination of most somatic symptoms. This decision has had the consequence of orphaning a large population of patients suffering from GAD that is more transient and somatic in its focus and who typically present not to psychiatrists but to primary care physicians. Therefore, clinicians should consider using the ICD-10 qualification of illness duration of "several months" to replace the more rigid DSM-IV criterion of 6 months and to move away from the DSM-IV focus on excessive worry as the cardinal symptom of anxiety and demote it to only another important anxiety symptom, similar to free-floating anxiety. One also might consider supplementing this ICD-10 criterion with an increased symptom severity criterion as, for example, a Hamilton Anxiety Scale of 18. Finally, the adjective excessive, not used in the definition of other primary diagnostic criteria, such as depressed mood for MDD, should be omitted (Table 3). 6. One may want to consider the distinction of trait (chronic) from state (acute) anxiety, but whether the presence of some personality characteristics, particularly anxious personality or Cluster C personality and increased neuroticism, as an indicator of trait [table: see text] anxiety is a prerequisite for anxiety disorders; occurs independently of anxiety disorders; or is a vulnerability factor that, in some patients, leads to anxiety symptoms and, in others, does not, is unknown. 7. Symptoms that some clinicians consider cardinal for a diagnosis of GAD, such as extreme worry, obsessive rumination, and somatization, also are present in other disorders, such as MDD. (ABSTRACT TRUNCATED)

Temporalis exteroceptive suppression in generalized anxiety disorder and major depression

The duration abnormality of the exteroceptive suppressions, or silent periods, of peripheral or jaw-closing muscle activities induced by transcranial magnetic or trigeminal electrical stimuli in patients suffering from anxiety or depression is ill-defined. We therefore studied the exteroceptive suppression periods of the temporalis muscle electromyography elicited by trigeminal territory electrical stimuli, Zuckerman-Kuhlman's Personality Questionnaire, and Plutchik-van Praag's Depression Inventory (PVP) in 12 patients suffering from generalized anxiety disorder (GAD) and 16 from major depression (MD) as well as in 17 healthy volunteers. Durations of the second suppression period (ES2) sociability scores were decreased in GAD patients, while PVP and neuroticism-anxiety scores were elevated in both GAD and MD patients. There was a positive correlation between ES2 duration and sociability score in the GAD group. This study indicates that anxiety can modify the temporalis ES2 duration through cortical descending inhibitory controls.