Towards DSM-V: the relationship between generalized anxiety disorder and major depressive episode

Gut Microbiome: A Potential Indicator for Differential Diagnosis of Major Depressive Disorder and General Anxiety Disorder

Background: Major depressive disorder (MDD) and general anxiety disorder (GAD) share many common features, leading to numerous challenges in their differential diagnosis. Given the importance of the microbiota-gut-brain axis, we investigated the differences in gut microbiota between representative cases of these two diseases and sought to develop a microbiome-based approach for their differential diagnosis. Methods: We enrolled 23 patients with MDD, 21 with GAD, and 10 healthy subjects (healthy crowd, HC) in the present study. We used 16S rRNA gene-sequencing analysis to determine the microbial compositions of the gut microbiome based on Illumina Miseq and according to the standard protocol. Results: GAD showed a significant difference in microbiota richness and diversity as compared with HC. Additionally, Otu24167, Otu19140, and Otu19751 were significantly decreased in MDD relative to HC, and Otu2581 and Otu10585 were significantly increased in GAD relative to MDD. At the genus level, the abundances of Sutterella and Fusicatenibacter were significantly lower in MDD relative to HC, and the abundances of Fusicatenibacter and Christensenellaceae_R7_group were significantly lower in GAD than in HC. The abundance of Sutterella was significantly higher whereas that of Faecalibacterium was significantly lower in GAD relative to MDD. Moreover, we observed that Christensenellaceae_R7_group negatively correlated with the factor score (Limited to Hopelessness) and total score of HAMD-24 (p < 0.05), whereas Fusicatenibacter negatively correlated with FT4 (p < 0.05). Furthermore, the GAD group showed significant differences at the genus level for Faecalibacterium, which negatively correlated with PTC (p < 0.05). Conclusions: This study elucidated a unique gut-microbiome signature associated with MDD and GAD that could facilitate differential diagnosis and targeted therapy.

The stability and change of etiological influences on depression, anxiety symptoms and their co-occurrence across adolescence and young adulthood

BACKGROUND

Depression and anxiety persist within and across diagnostic boundaries. The manner in which common v. disorder-specific genetic and environmental influences operate across development to maintain internalizing disorders and their co-morbidity is unclear. This paper investigates the stability and change of etiological influences on depression, panic, generalized, separation and social anxiety symptoms, and their co-occurrence, across adolescence and young adulthood.

METHOD

A total of 2619 twins/siblings prospectively reported symptoms of depression and anxiety at mean ages 15, 17 and 20 years.

RESULTS

Each symptom scale showed a similar pattern of moderate continuity across development, largely underpinned by genetic stability. New genetic influences contributing to change in the developmental course of the symptoms emerged at each time point. All symptom scales correlated moderately with one another over time. Genetic influences, both stable and time-specific, overlapped considerably between the scales. Non-shared environmental influences were largely time- and symptom-specific, but some contributed moderately to the stability of depression and anxiety symptom scales. These stable, longitudinal environmental influences were highly correlated between the symptoms.

CONCLUSIONS

The results highlight both stable and dynamic etiology of depression and anxiety symptom scales. They provide preliminary evidence that stable as well as newly emerging genes contribute to the co-morbidity between depression and anxiety across adolescence and young adulthood. Conversely, environmental influences are largely time-specific and contribute to change in symptoms over time. The results inform molecular genetics research and transdiagnostic treatment and prevention approaches.

DSM-5 reviewed from different angles: goal attainment, rationality, use of evidence, consequences--part 1: general aspects and paradigmatic discussion of depressive disorders

DSM-5 was published in 2013 after about 10 years of preparation. Part 1 of this paper discusses several more general aspects of DSM-5 and offers a detailed, paradigmatic analysis of changes made to the chapter on depressive disorders. The background for the changes is analysed on the basis of a PubMed search and review papers on the classification of mental disorders in general and on empirical knowledge about individual disorders. Contrary to the original plans, DSM-5 has not introduced a primarily dimensional diagnostic system but has widely preserved the categorical system of disorders. Also, it has not adopted a more neurobiological approach to disorders by including biological markers to increase the objectivity of psychiatric diagnoses but has maintained the primarily symptom-based, descriptive approach. The criteria for some disorders have been changed, including affective, schizophrenic and addiction disorders, and a few new disorders have been added. A minimal version of the dimensional approach was realised through the introduction of several transnosological specifiers and the option to make symptom- or syndrome-related severity and dimensional assessments. These specifiers and assessments might allow a more individualised description of a patient's psychopathological state and more personalised treatment. However, most of the symptom- and syndrome-related assessments are not mandatory and therefore may not be used in clinical practice.

Anxious forms of depression

Previous research has described distinctive features for anxious and nonanxious forms of major depression. The concept of "mixed anxiety depression disorder" (MADD) refers to a milder degree of the anxious form of depression, since the depressive symptoms fall short of the number required for a diagnosis of major depression. It is argued that this can be thought of as a subclinical form of anxious depression, rather than a separate disorder in its own right. In view of its substantial prevalence in general medical settings, its associated disability and its public health importance, it deserves to be recognized, and seen as being continuous with the more severe forms of anxious depression. It will therefore be included in the Field Trials of the version of the ICD-11 (where ICD is the International Classification of Disease) intended for primary care. It is argued that current anxiety, depression (without anxiety), and anxious depression would cover most of the psychologically distressed patients seen in general medical settings, using a pseudodimensional system.

The latent structure of generalized anxiety disorder in midlife adults

Generalized anxiety disorder (GAD) is identified as a discrete disorder in the DSM-5, but evidence suggests that GAD and the related construct of pathological worry possesses a dimensional latent structure. The objective of this study was to ascertain the latent structure of GAD using taxometric methods. A subsample of adults (N=2061) from the Midlife in the United States Study, a national sample of Americans, provided the data. Additional data from individuals who were re-interviewed 10 year later (n=1228) were also analyzed. Items corresponding to the DSM-IV-TR diagnostic criteria for GAD were used to generate indicators for the taxometric analyses. Multiple taxometric procedures provided no evidence that GAD has a categorical or taxonic latent structure. Instead, the results were more consistent with the proposition that GAD exists on a continuum. Evidence that GAD is dimensional suggests that dichotomizing individuals into GAD versus non-GAD groups will typically result in decreased statistical power. They also suggest that any diagnostic thresholds for identifying GAD are likely to be arbitrary. The findings are consistent with models that locate GAD within the framework of extant dimensional models of personality and with research that emphasizes a multifactorial etiology for GAD.

Worry and generalized anxiety disorder: a review and theoretical synthesis of evidence on nature, etiology, mechanisms, and treatment

Generalized anxiety disorder (GAD) is associated with substantial personal and societal cost yet is the least successfully treated of the anxiety disorders. In this review, research on clinical features, boundary issues, and naturalistic course, as well as risk factors and maintaining mechanisms (cognitive, biological, neural, interpersonal, and developmental), are presented. A synthesis of these data points to a central role of emotional hyperreactivity, sensitivity to contrasting emotions, and dysfunctional attempts to cope with strong emotional shifts via worry. Consistent with the Contrast Avoidance model, evidence shows that worry evokes and sustains negative affect, thereby precluding sharp increases in negative emotion. We also review current treatment paradigms and suggest how the Contrast Avoidance model may help to target key fears and avoidance tendencies that serve to maintain pathology in GAD.

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.

Prevalence and correlates of generalized anxiety disorder among older adults in the Australian National Survey of Mental Health and Well-Being

BACKGROUND

Generalized anxiety disorder (GAD) occurs commonly, with widespread consequences including decreased functioning and wellbeing, and increased consumption of health resources. Notwithstanding its prevalence and impact, knowledge about GAD in older adults is still scarce. Accordingly, the main goals of this study were to estimate the prevalence and analyze the correlates of 12-month DSM-IV GAD in older community-residing adults.

METHODS

The sample was drawn from the 2007 Australian National Survey of Mental Health and Well-Being and consisted of 3035 participants aged between 55 and 85years, assessed by lay interviewers with the fully-structured Composite International Diagnostic Interview.

RESULTS

Eighty-four participants were diagnosed with GAD, equivalent to a weighted 12-month population prevalence of 2.8% (95% CI: 2.0, 3.7). In a multivariate logistic regression model older age (OR=0.24, p=0.006), functional limitations (OR=1.07, p=0.001), lifetime depression comorbidity (OR=5.31, p<0.001), concerns about having a serious illness despite doctor's reassurance (OR=2.29, p=0.021), and family history of anxiety or depression (OR=2.41, p=0.007) were the most significant predictors of 12-month GAD in older adults.

LIMITATIONS

This was a cross sectional study, limiting causal inferences.

CONCLUSIONS

In community-residing older adults GAD is highly prevalent and strongly associated with functional limitations, psychiatric comorbidity and increased medication intake. These findings suggest the need for greater clinical awareness of GAD among older adults.

Relationship between symptoms of anxiety and depression in a sample of Arab college students using the Hopkins Symptom Checklist 25

BACKGROUND

The controversy over the relationship between symptoms of anxiety and depression is an enduring issue. Various models have been proposed to explain this relationship. We explored the following research questions. First, using exploratory factor analysis (EFA), will the symptoms that define anxiety and depression (as in the Hopkins Symptom Checklist 25, HSCL-25) appear together in 1 factor, or are they separable into the hypothesized dimensions of the disorders? Second, using confirmatory factor analysis, how will the structural integrity of the resulting factors compare with those of the various models that have been proposed to explain the relationship between the symptoms of anxiety and depression? This issue has not been investigated in an Arab setting.

METHOD

Participants (n = 624) were Kuwaiti national college students, who completed the HSCL-25 in class. EFA was done by principal axis factoring. Seven models were generated for comparison in confirmatory factor analysis, using 8 'fit' indices in Analysis of Moment Structures, version 16.

RESULTS

The 5 factors from EFA were similar in construct to the subscales of the Mood and Anxiety Symptom Questionnaire, on which the tripartite model of anxiety and depression was validated ('core anxiety', 'core depression', 'general distress mixed', 'general distress anxiety', 'general distress depression'). The hierarchical bifactor model and the dimensional model characterized by the correlation of these factors were best at meeting the fit indices, followed by the correlated 2-factor anxiety/depression model. In line with theory, the correlation between the specific anxiety/depression factors was lower than that between each of them and the general distress mixed factor; and there was no significant gender difference in the summed score for core depression.

CONCLUSION

The findings support the impression that, although the core symptoms of anxiety are separable from the core symptoms of depression, there is an overlapping set of symptoms which contribute to the experience of comorbidity. The relationship between symptoms of anxiety and depression probably has dimensional and hierarchical elements. The findings broaden the evidence base of the cross-cultural validity of the tripartite model.

Longitudinal dimensionality of adolescent psychopathology: testing the differentiation hypothesis

BACKGROUND

The differentiation hypothesis posits that the underlying liability distribution for psychopathology is of low dimensionality in young children, inflating diagnostic comorbidity rates, but increases in dimensionality with age as latent syndromes become less correlated. This hypothesis has not been adequately tested with longitudinal psychiatric symptom data.

METHODS

Confirmatory factor analyses of DSM-IV symptoms from seven common Axis I syndromes--major depression, generalized anxiety, separation anxiety, social anxiety, attention deficient hyperactivity, conduct, and oppositional defiant disorders--were conducted longitudinally, from ages 9 to 16, using the general-population Great Smoky Mountains Study sample.

RESULTS

An eight-syndrome model fit well at all ages, and in both genders. It included social anxiety, separation anxiety, oppositional defiant, and conduct syndromes, along with a multidimensional attention deficit-hyperactivity syndrome (i.e., inattention, hyperactivity, and impulsivity) and a unidimensional major depression/generalized anxiety syndrome. A high degree of measurement invariance across age was found for all syndromes, except for major depression/generalized anxiety. Major depression and generalized anxiety syndromes slightly diverged at age 14-16, when they also began to explain more symptom variance. Additionally, correlations between some emotional and disruptive syndromes showed slight differentiation.

CONCLUSIONS

Marked developmental differentiation of psychopathology, as implied by the orthogenetic principle, is not a prominent cause of preadolescent and adolescent psychiatric comorbidity.

A hierarchical model for the relationships between general and specific vulnerability factors and symptom levels of generalized anxiety disorder

The present study examined a hierarchical model for the relationships between general and specific vulnerability factors and symptom manifestations of generalized anxiety disorder (GAD). A clinical sample of patients with GAD (N=137) completed a set of self-report questionnaires for measuring neuroticism, extraversion, intolerance of uncertainty, metacognitive beliefs, and symptoms of generalized anxiety (i.e., worry) and depression. A bootstrapping analysis yielded support for a model in which the relation between the general vulnerability factor of neuroticism and symptoms of GAD were mediated by the specific vulnerability factors of intolerance of uncertainty and negative metacognitions. Implications for the classification and treatment of GAD are discussed.

Comorbidity of depressive and anxiety disorders for older Americans in the national comorbidity survey-replication

OBJECTIVE

To identify age differences in the 12-month and lifetime comorbidity of depressive and anxiety disorders for adults (18-64 years) compared with older adults (65 years and older) in a nationally representative sample of community-dwelling adults in the United States.

DESIGN

Cross-sectional epidemiologic study, using data from the National Comorbidity Survey-Replication public use dataset.

SETTING

Community-based epidemiologic survey.

PARTICIPANTS

Representative national sample of community-dwelling adults in the United States.

MEASUREMENTS

The World Health Organization Composite International Diagnostic Interview was used to assess Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition psychiatric disorders.

RESULTS

More than half of respondents with a 12-month major depressive disorder (MDD) had a comorbid anxiety disorder or dysthymia (18-64 years = 60.6%; 65 years and older = 51.8%). High rates of MDD were also found for those with anxiety disorders across both age groups, highest in the 18-64 years group for generalized anxiety disorder (28.5%) and highest in the 65 years and older group for panic disorder (36.7%). Age group did not predict 12-month diagnosis of a comorbid anxiety disorder among those with a depressive disorder in multivariate logistic regression. Onset of anxiety disorders preceded onset of depressive disorders for most older adults (77.6%).

CONCLUSIONS

Depressive and anxiety disorders frequently cooccurred in this representative sample of community-dwelling adults. Older adults experienced comorbidity to a similar extent as younger adults, suggesting high rates of comorbidity across the lifespan.

Distinct profiles of anxiety and dysphoria during spontaneous withdrawal from acute morphine exposure

The negative motivational aspects of withdrawal include symptoms of both anxiety and depression, and emerge after termination of chronic drug use as well as after acute drug exposure. States of acute withdrawal are an inherent part of intermittent drug use in humans, but the contribution of acute withdrawal to the development of addiction has received limited systematic investigation, because of a lack of preclinical models for withdrawal states that emerge spontaneously after acute drug exposure. Here, we have characterized a spontaneous increase in the magnitude of the acoustic startle reflex (ie, spontaneous withdrawal-potentiated startle) that emerges after acute morphine administration in rats, and compared the time course of startle potentiation and place conditioning. We find that startle potentiation seems to be related to a decrease in opiate receptor occupancy and reflects an anxiety-like state with a pharmacological profile similar to other signs of opiate withdrawal. Spontaneous startle potentiation emerges before the rewarding effects of morphine have subsided, even though naloxone administration after a single morphine exposure causes both startle potentiation and conditioned place aversion (CPA). These results show that negative emotional signs of withdrawal develop after just one exposure to morphine, and are likely a recurrent aspect of intermittent drug use that may contribute to the earliest adaptations underlying the development of addiction. Furthermore, the dissociation between spontaneous startle potentiation and CPA suggests anxiogenic and dysphoric manifestations of opiate withdrawal may be mediated by distinct neural mechanisms that are progressively engaged as withdrawal unfolds.