Development and validation of new anxiety and bipolar symptom scales for an expanded version of the IDAS (the IDAS-II)

Diagnostic and symptom-based predictors of emotional processing in generalized anxiety disorder and major depressive disorder: An event-related potential study

The delineation of specific versus overlapping mechanisms in GAD and MDD could shed light on the integrity of these diagnostic categories. For example, negative emotion generation is one mechanism that may be especially relevant to both disorders. Emotional processing abnormalities were examined among 97 outpatients with generalized anxiety disorder (GAD) or major depressive disorder (MDD) and 25 healthy adults, using the late positive potential (LPP), an event-related potential that is larger for emotional versus neutral stimuli. GAD and MDD were also assessed dimensionally across all participants. Both MDD diagnosis and dimensional depression scores were associated with reduced ΔLPP. When controlling for MDD diagnosis/dimension, both the diagnosis and dimension of GAD were associated with increased ΔLPP. Both MDD and GAD dimensions, but not diagnoses, were associated with increased ΔRT to targets that followed emotional pictures. Therefore, MDD and GAD have distinguishable and opposing features evident in neural measures of emotion processing.

Blunted neural response to rewards as a vulnerability factor for depression: Results from a family study

Depressive disorders are associated with significant economic and public health burdens as well as increased morbidity. Yet, perhaps due to the heterogeneous nature of the disease, prevention and intervention efforts are only moderately efficacious. A better understanding of core mechanisms of depressive disorders might aid in the development of more targeted intervention, and perhaps help identify individuals at risk. One mechanism that may be particularly important to depressive phenotypes is reward insensitivity. Examination of neurobiological correlates of reward-processing, which should relate more directly to the neuropathology of depression, may be helpful in identifying liability for the disorder. To that end, we used a family study design to examine whether a neural response to rewards is a familial risk factor for depression in a sample of probands with a wide range of internalizing psychopathology, as well as their biological siblings. Event-related potentials were recorded during a simple forced-choice gambling paradigm, in which participants could either win or lose small amounts of money. Lower levels of positive affect in probands predicted a reduced neural response to rewards in siblings, even over and above the sibling's own level of positive and negative affect. Additionally, the neural response to rewards was familial (i.e., correlated among siblings). Combined, these analyses suggest that a blunted neural response to rewards may be useful in identifying individuals vulnerable to depressive illnesses.

The structure and short-term stability of the emotional disorders: a dimensional approach

BACKGROUND

Factor-analytic studies have found that depressive, bipolar, post-traumatic, obsessive-compulsive, and anxiety disorders - jointly referred to as the emotional disorders - form an internalizing spectrum that includes distress and fear subfactors. However, placement of some disorders is uncertain. Also, prior research analysed dichotomous interview-based diagnoses or dimensional self-report measures. We investigated this structure using a third-generation measure - the Interview for Mood and Anxiety Symptoms (IMAS) - that combines strengths of a clinical interview with dimensional assessment.

METHOD

The interview was administered to 385 students and 288 psychiatric out-patients. Participants were reinterviewed 2 months later.

RESULTS

Exploratory and confirmatory factor analyses identified three factors: distress (depression, generalized anxiety, post-traumatic stress, irritability, and panic syndrome); fear (social anxiety, agoraphobia, specific phobia, and obsessive-compulsive); and bipolar (mania and obsessive-compulsive). The structure was consistent over time and across samples, except that panic and agoraphobia had higher factor loadings in patients. Longitudinal analyses revealed high temporal stability of the factors (test-retest r = 0.72 to 0.87), but also substantial disorder-specific stability.

CONCLUSIONS

This investigation - which bridges diagnostic and self-report studies - found three subfactors of internalizing psychopathology. It provided support for a new subfactor, clarified the placement of obsessive-compulsive and bipolar disorders, and demonstrated that this model generalizes across populations. The accumulating research suggests the need to recognize formally the close links among the emotional disorders, as well as empirical clusters within this spectrum. The IMAS demonstrated strong psychometric properties and can be useful for various research and clinical applications by providing dimensional, interview-based assessment of the emotional disorders.

Familial risk for distress and fear disorders and emotional reactivity in adolescence: an event-related potential investigation

BACKGROUND

The late positive potential (LPP) is an event-related potential component that is sensitive to the motivational salience of stimuli. Children with a parental history of depression, an indicator of risk, have been found to exhibit an attenuated LPP to emotional stimuli. Research on depressive and anxiety disorders has organized these conditions into two empirical classes: distress and fear disorders. The present study examined whether parental history of distress and fear disorders was associated with the LPP to emotional stimuli in a large sample of adolescent girls.

METHOD

The sample of 550 girls (ages 13.5-15.5 years) with no lifetime history of depression completed an emotional picture-viewing task and the LPP was measured in response to neutral, pleasant and unpleasant pictures. Parental lifetime history of psychopathology was determined via a semi-structured diagnostic interview with a biological parent, and confirmatory factor analysis was used to model distress and fear dimensions.

RESULTS

Parental distress risk was associated with an attenuated LPP to all stimuli. In contrast, parental fear risk was associated with an enhanced LPP to unpleasant pictures but was unrelated to the LPP to neutral and pleasant pictures. Furthermore, these results were independent of the adolescent girls' current depression and anxiety symptoms and pubertal status.

CONCLUSIONS

The present study demonstrates that familial risk for distress and fear disorders may have unique profiles in terms of electrocortical measures of emotional information processing. This study is also one of the first to investigate emotional/motivational processes underlying the distress and fear disorder dimensions.

Abnormal amygdala resting-state functional connectivity in adolescent depression

IMPORTANCE

Major depressive disorder (MDD) frequently emerges during adolescence and can lead to persistent illness, disability, and suicide. The maturational changes that take place in the brain during adolescence underscore the importance of examining neurobiological mechanisms during this time of early illness. However, neural mechanisms of depression in adolescents have been understudied. Research has implicated the amygdala in emotion processing in mood disorders, and adult depression studies have suggested amygdala-frontal connectivity deficits. Resting-state functional magnetic resonance imaging is an advanced tool that can be used to probe neural networks and identify brain-behavior relationships.

OBJECTIVE

To examine amygdala resting-state functional connectivity (RSFC) in adolescents with and without MDD using resting-state functional magnetic resonance imaging as well as how amygdala RSFC relates to a broad range of symptom dimensions.

DESIGN, SETTING, AND PARTICIPANTS

A cross-sectional resting-state functional magnetic resonance imaging study was conducted within a depression research program at an academic medical center. Participants included 41 adolescents and young adults aged 12 to 19 years with MDD and 29 healthy adolescents (frequency matched on age and sex) with no psychiatric diagnoses.

MAIN OUTCOMES AND MEASURES

Using a whole-brain functional connectivity approach, we examined the correlation of spontaneous fluctuation of the blood oxygen level-dependent signal of each voxel in the whole brain with that of the amygdala.

RESULTS

Adolescents with MDD showed lower positive RSFC between the amygdala and hippocampus, parahippocampus, and brainstem (z >2.3, corrected P < .05); this connectivity was inversely correlated with general depression (R = -.523, P = .01), dysphoria (R = -.455, P = .05), and lassitude (R = -.449, P = .05) and was positively correlated with well-being (R = .470, P = .03). Patients also demonstrated greater (positive) amygdala-precuneus RSFC (z >2.3, corrected P < .05) in contrast to negative amygdala-precuneus RSFC in the adolescents serving as controls.

CONCLUSIONS AND RELEVANCE

Impaired amygdala-hippocampal/brainstem and amygdala-precuneus RSFC have not previously been highlighted in depression and may be unique to adolescent MDD. These circuits are important for different aspects of memory and self-processing and for modulation of physiologic responses to emotion. The findings suggest potential mechanisms underlying both mood and vegetative symptoms, potentially via impaired processing of memories and visceral signals that spontaneously arise during rest, contributing to the persistent symptoms experienced by adolescents with depression.

Replicable Facets of Positive Emotionality and Their Relations to Psychopathology

General individual differences in positive emotionality are negatively related to depression, social anxiety, and schizotypy/schizophrenia, and positively related to mania. However, the structure of positive emotionality remains unclear at the facet level, as there are significant disparities in the types of content assessed across emotionality measures. This study analyzed the lower order structure of positive emotionality in two samples, finding evidence for a replicable two-factor structure of Joviality and Experience Seeking. These factors demonstrated a markedly different pattern of relations in both direction and magnitude with internalizing, externalizing, and schizotypal symptoms. Joviality seems to represent an adaptive variant of positive emotionality, as it showed strong positive relations with well-being and moderate negative relations with measures of depression, social anxiety, and social anhedonia. In contrast, Experience Seeking appears to be somewhat maladaptive. It generally related positively to psychopathology, correlating most strongly with indicators of manic and externalizing symptoms.

Assessment of postpartum depressive symptoms: the importance of somatic symptoms and irritability

Assessing postpartum depressive symptoms is complicated by the fact that irritability, fatigue, insomnia, and appetite disruptions are also related to normative aspects of the childbearing process. We used multigroup confirmatory factor analysis to compare symptoms in 271 postpartum women with those of 820 non-postpartum women. We found that (a) irritability, insomnia, fatigue, and appetite loss were substantially associated with depressed mood among postpartum women whereas increased appetite was not; (b) irritability, insomnia, fatigue, and appetite changes were as strongly related to depression among postpartum women as they were among non-postpartum women; and (c) after controlling for overall depressed mood, postpartum women reported more irritability, insomnia, and appetite loss than the non-postpartum women. Irritability, fatigue, insomnia, and appetite loss are valid indicators and should be used to measure postpartum depressive symptoms. However, scores on these symptoms should be adjusted downward to account for their higher baseline rates in the postpartum population.

Measuring Dimensions of Posttraumatic Stress Disorder

Researchers have suggested that the symptoms of posttraumatic stress disorder (PTSD) should be divided into the four dimensions of intrusions, avoidance, numbing or dysphoria, and hyperarousal. However, the clinical utility of a dysphoria/general distress symptom dimension is unclear, and measures of the overall structure of PTSD are limited by the small number of avoidance and prototypical hyperarousal symptoms in the Diagnostic and Statistical Manual of Mental Disorders ( DSM). The Iowa Traumatic Response Inventory (ITRI) was created as a broader measure of symptoms related to PTSD. The factor analytic method of test construction was used to create the scales from a larger pool of items. The measure was validated in a clinical sample and in a student sample. Analysis of the ITRI symptom dimensions suggests traumatic intrusions and avoidance symptoms are highly associated and are specific to PTSD, whereas dysphoria, hyperarousal, and dissociation are not specific to PTSD. Overall, the ITRI was found to be a reliable and valid measure of PTSD symptoms that better captures the observed structure of the disorder.

Personality, Emotions, and the Emotional Disorders

We examined symptom-level relations between the emotional disorders and general traits within the five-factor model of personality. Neuroticism correlated strongly with the general distress/negative affectivity symptoms (depressed mood, anxious mood, worry) that are central to these disorders; more moderately with symptoms of social phobia, affective lability, panic, posttraumatic stress disorder, lassitude, checking, and obsessive intrusions; and more modestly with agoraphobia, specific phobia, and other symptoms of depression and obsessive-compulsive disorder. Extraversion was negatively correlated with symptoms of social anxiety/social phobia and was positively related to scales assessing expansive positive mood and increased social engagement in bipolar disorder. Conscientiousness, agreeableness, and openness showed weaker associations and generally added little to the prediction of these symptoms. It is noteworthy, moreover, that our key findings replicated well across (a) self-rated versus (b) interview-based symptom measures. We conclude by discussing the diagnostic and assessment implications of these data.

Beyond a single index of mania symptoms: structure and validity of subdimensions

BACKGROUND

DSM-5 portrays mania as unitary despite evidence of distinct symptom clusters. Studies investigating the structure of mania have been inconsistent, in part because many relied on instruments not designed for this question. The present work used a clinical interview designed for structural analysis in order to identify and validate subdimensions specific to mania symptoms.

METHODS

Psychiatric outpatients (N=422) and undergraduates with a history of mental health treatment (N=306) were interviewed with a comprehensive measure of mood and anxiety that included 24 manic symptoms. Patients completed additional measures of symptoms and functioning, and a semi-structured diagnostic interview.

RESULTS

A 4-factor model of mania replicated across independent samples and was superior in fit to competing models, including the unidimensional model implied whenever researchers or clinicians use only a total score for mania. The factors were only moderately correlated, and three of the four ("Irritability" was the exception) showed a strong criterion, convergent and discriminant validity, suggesting they are specific to mania. Subdimensions showed distinct and meaningful associations with functioning.

LIMITATIONS

Symptoms of psychosis and depression are important features of manic episodes, but were not included in the present study since they lack specificity to mania.

CONCLUSIONS

Mania is multifaceted. At least three subdimensions specific to mania were identified ("Euphoric Activation," "Hyperactive Cognition" and "Reckless Overconfidence"). Use of subdimensions, in addition to overall mania severity, may enhance the ability of studies to detect meaningful biological correlates of bipolar disorder. Moreover, their different associations with functioning suggest assessing subdimensions has clinical utility as well.

PTSD symptom dimensions and their relationship to functioning in World Trade Center responders

Post-traumatic stress disorder (PTSD) symptoms are common among responders to the 9/11 attacks on the World Trade Center and can lead to impairment, yet it is unclear which symptom dimensions are responsible for poorer functioning. Moreover, how best to classify PTSD symptoms remains a topic of controversy. The present study tested competing models of PTSD dimensions and then assessed which were most strongly associated with social/occupational impairment, depression, and alcohol abuse. World Trade Center responders (n=954) enrolled in the Long Island site of the World Trade Center Health Program between 2005 and 2006 were administered standard self-report measures. Confirmatory factor analysis confirmed the superiority of four-factor models of PTSD over the DSM-IV three-factor model. In selecting between four-factor models, evidence was mixed, but some support emerged for a broad dysphoria dimension mapping closely onto depression and contributing strongly to functional impairment. This study confirmed in a new population the need to revise PTSD symptom classification to reflect four dimensions, but raises questions about how symptoms are categorized. Results suggest that targeted treatment of symptoms may provide the most benefit, and that treatment of dysphoria-related symptoms in disaster relief workers may have the most benefit for social and occupational functioning.

The value of suppressor effects in explicating the construct validity of symptom measures

Suppressor effects are operating when the addition of a predictor increases the predictive power of another variable. We argue that suppressor effects can play a valuable role in explicating the construct validity of symptom measures by bringing into clearer focus opposing elements that are inherent--but largely hidden--in the measure's overall score. We illustrate this point using theoretically grounded, replicated suppressor effects that have emerged in analyses of the original Inventory of Depression and Anxiety Symptoms (IDAS; Watson et al., 2007) and its expanded 2nd version (IDAS-II; Watson et al., 2012). In Study 1, we demonstrate that the IDAS-II Appetite Gain and Appetite Loss scales contain both (a) a shared distress component that creates a positive correlation between them and (b) a specific symptom component that produces a natural negative association between them (i.e., people who recently have experienced decreased interest in food/loss of appetite are less likely to report a concomitant increase in appetite/weight). In Study 2, we establish that mania scales also contain 2 distinct elements-namely, high energy/positive emotionality and general distress/dysfunction-that oppose each another in many instances. In both studies, we obtained evidence of suppression effects that were highly robust across different types of respondents (e.g., clinical outpatients, community adults, college students) and using both self-report and interview-based measures. These replicable suppressor effects establish that many homogeneous, unidimensional symptom scales actually contain distinguishable components with distinct--at times, even antagonistic--properties.

Validity of somatic symptoms as indicators of depression in pregnancy

Somatic symptoms (e.g., fatigue, appetite changes, and sleep disruption) are common to both pregnancy and depression. The goal of the present study was to examine the validity of somatic symptoms as indicators of depression during pregnancy. The Inventory of Depression and Anxiety Symptoms (IDAS) was administered to a cross-sectional sample of 255 pregnant women as well as 820 women from five community-based samples, who served as a control group. Confirmatory factor analysis (CFA) was used to evaluate the fit of a single-factor model of depression in pregnant and community samples. Multigroup CFA was used to test the invariance of the factor loadings of eight depression-related symptom scales. The fit for a one-factor model was adequate for both the pregnant and community samples. All eight IDAS scales were valuable indicators of depression in the community group; however, Appetite Loss and Appetite Gain were poor indicators of depression among the pregnant women. The factor loadings for Lassitude and Appetite Gain were significantly weaker amongst the pregnant women than community women. The magnitude of the factor loadings for Insomnia and Well Being were significantly greater for the pregnant group. With the exception of appetite disturbance, somatic symptoms, though a common occurrence during pregnancy, are valid indicators of depression during pregnancy. When assessing for prenatal depression, somatic symptoms should not necessarily be dismissed as normative pregnancy experiences.

Core OCD symptoms: exploration of specificity and relations with psychopathology

Obsessive-compulsive disorder (OCD) is a heterogeneous condition, comprised of multiple symptom domains. This study used aggregate composite scales representing three core OCD dimensions (Checking, Cleaning, and Rituals), as well as Hoarding, to examine the discriminant validity, diagnostic specificity, and predictive ability of OCD symptom scales. The core OCD scales demonstrated strong patterns of convergent and discriminant validity - suggesting that these dimensions are distinct from other self-reported symptoms - whereas hoarding symptoms correlated just as strongly with OCD and non-OCD symptoms in most analyses. Across analyses, our results indicated that Checking is a particularly strong, specific marker of OCD diagnosis, whereas the specificity of Cleaning and Hoarding to OCD was less strong. Finally, the OCD Checking scale was the only significant predictor of OCD diagnosis in logistic regression analyses. Results are discussed with regard to the importance of assessing OCD symptom dimensions separately and implications for classification.