Examination of the relations between obsessive-compulsive symptom dimensions and fear and distress disorder symptoms

Event-related potentials to acoustic startle probes during unpredictable threat are associated with individual differences in intolerance of uncertainty

Individual differences in sensitivity to unpredictable threat may be a critical mechanism for internalizing psychopathology phenotypes. The present study examined whether the startle probe-elicited N100 and P300 during unpredictable threat - two event-related potentials indexing early and elaborative attentional processing of unpredictable threat - may be endophenotypes for internalizing psychopathology, including fear and distress/misery disorders and intolerance of uncertainty (IU), a clinical trait that is transdiagnostically associated with internalizing disorders. A large sample of adult siblings (N = 375) completed the no, predictable, and unpredictable threat task, during which the N100 and P300 were recorded. Relative to the no threat condition, N100 was more strongly enhanced in anticipation of unpredictable than predictable threat while P300 was suppressed to both predictable and unpredictable threat. While neither N100 enhancement nor P300 suppression to unpredictable threat was associated with fear or distress/misery disorders, they were negatively linked to inhibitory IU (a facet of IU). Thus, individuals high in inhibitory IU showed reduced attentional engagement with the threatening context when it was unpredictable. Further, N100 enhancement and, to a lesser degree, P300 suppression to unpredictable threat showed familial aggregation - a key criterion for determining whether a biomarker is an endophenotype. In sum, N100 enhancement and P300 suppression to unpredictable threat may be endophenotypes for dimensional measures of internalizing psychopathology.

Escitalopram and lorazepam differentially affect nesting and open field behaviour in deer mice exposed to an anxiogenic environment

Large nest building behaviour (LNB), as expressed by a subpopulation of laboratory housed deer mice (Peromyscus maniculatus bairdii), is persistent and repetitive. However, the response of LNB to an anxiogenic environment has not yet been investigated. Here, we employed LNB and normal nesting (NNB) expressing mice, subdivided into three drug-exposed groups per cohort, i.e. water (28 days), escitalopram (50 mg/kg/day, 28 days) and lorazepam (2 mg/kg/day; 4 days) to investigate this theme. During the last 4 days of drug exposure, mice were placed inside anxiogenic open field arenas which contained a separate enclosed and dark area for 4 consecutive nights during which open field and/or nest building assessments were performed. We show that LNB behaviour in deer mice is stable, irrespective of the anxiety-related context in which it is assessed, and that LNB mice find an open field arena to be less aversive compared to NNB mice. Escitalopram and lorazepam differentially affected the nesting and open field behaviour of LNB expressing mice, confirming deer mouse LNB as a repetitive behavioural phenotype that is related to a compulsive-like process which is regulated by the serotonergic system.

Fear conditioning and extinction in obsessive-compulsive disorder: A systematic review

Laboratory experiments using fear conditioning and extinction protocols help lay the groundwork for designing, testing, and optimizing innovative treatments for anxiety-related disorders. Yet, there is limited basic research on fear conditioning and extinction in obsessive-compulsive disorder (OCD). This is surprising because exposure-based treatments based on associative learning principles are among the most popular and effective treatment options for OCD. Here, we systematically review and critically assess existing aversive conditioning and extinction studies of OCD. Across 12 studies, there was moderate evidence that OCD is associated with abnormal acquisition of conditioned responses that differ from comparison groups. There was relatively stronger evidence of OCD's association with impaired extinction processes. This included multiple studies finding elevated conditioned responses during extinction learning and poorer threat/safety discrimination during recall, although a minority of studies yielded results inconsistent with this conclusion. Overall, the conditioning model holds value for OCD research, but more work is necessary to clarify emerging patterns of results and increase clinical translational utility to the level seen in other anxiety-related disorders. We detail limitations in the literature and suggest next steps, including modeling OCD with more complex conditioning methodology (e.g., semantic/conceptual generalization, avoidance) and improving individual-differences assessment with dimensional techniques.

Stereotypy and spontaneous alternation in deer mice and its response to anti-adenosinergic intervention

Repetitive behavioral phenotypes are a trait of several neuropsychiatric disorders, including obsessive-compulsive disorder (OCD). Such behaviors are typified by complex interactions between cognitive and neurobiological processes which most likely contribute to the suboptimal treatment responses often observed. To this end, exploration of the adenosinergic system may be useful, since adenosine-receptor modulation has previously shown promise to restore control over voluntary behavior and improve cognition in patients presenting with motor repetition. Here, we employed the deer mouse (Peromyscus maniculatus bairdii) model of compulsive-like behavioral persistence, seeking to investigate possible associations between stereotypic motor behavior and cognitive flexibility as measured in the T-maze continuous alternation task (T-CAT). The effect of istradefylline, a selective adenosine A_2A receptor antagonist at two doses (10 and 20 mg kg^-1  day^-1 ) on the expression of stereotypy and T-CAT performance in high (H) and non-(N) stereotypical animals, was investigated in comparison to a control intervention (six groups; n = 8 or 9 per group). No correlation between H behavior and T-CAT performance was found. However, H but not N animals presented with istradefylline-sensitive spontaneous alternation and stereotypy, in that istradefylline at both doses significantly improved the spontaneous alternation scores and attenuated the stereotypical expression of H animals. Thus, evidence is presented that anti-adenosinergic drug action improves repetitive behavior and spontaneous alternation in stereotypical deer mice, putatively pointing to a shared psychobiological construct underlying naturalistic stereotypy and alterations in cognitive flexibility in deer mice.

The comorbidity structure of fear, distress and compulsive disorders in an acute psychiatric sample

Body dysmorphic disorder (BDD) and obsessive-compulsive disorder (OCD), collectively referred to as compulsive disorders, have typically not been included in structural research on the internalizing spectrum due to low prevalence in community samples. The current study examined the higher-order structure of anxiety, depressive and compulsive disorders among patients in a psychiatric partial hospital program (N = 2,178). We applied confirmatory factor analysis to diagnostic data obtained at admission and compared several competing models of the comorbidity structure. A one-factor model accounted well for the co-occurrence of all the disorders. A two-factor model comprised of fear and distress factors, wherein compulsive disorders loaded on fear, also fit the data well. However, a very large factor correlation (r = 0.86) suggested limited discriminant validity of fear and distress in the sample. Alternate models that featured a distinct compulsivity factor were not viable owing to large correlations between fear and compulsive disorders. Overall, our findings indicate that a broad internalizing dimensions underlies not only anxiety and depression, but also compulsive disorders, in an acute psychiatric population. Future studies using symptom-level data are needed to replicate these results and determine the structure of internalizing disorders from the bottom up, starting with narrowly defined symptom components.

Distress Tolerance as a Familial Vulnerability for Distress-Misery Disorders

Low perceived distress tolerance (DT), a trait-like individual difference factor reflecting one's perceived ability to withstand aversive affective states, has been linked with current internalizing and substance use disorders (SUDs). However, perceived DT has not been systematically evaluated as a familial, transdiagnostic vulnerability factor for internalizing and SUDs. The current study tested whether perceived DT runs in families and whether it is reduced among individuals with versus without remitted internalizing/SUD psychopathology. Perceived DT and internalizing/SUDs were measured in 638 individuals (nested within 256 families). Analyses also adjusted for the effects of neuroticism to test whether DT was a specific vulnerability factor independent of temperamental negative affect. Analyses revealed that perceived DT was lower in individuals with remitted distress (i.e., major depression, generalized anxiety disorder, posttraumatic stress disorder) but not fear disorders (i.e., panic disorder, social anxiety disorder, specific phobia, obsessive-compulsive spectrum disorders) relative to healthy controls, and the effect of distress-misery disorder history remained significant when adjusting for neuroticism. Perceived DT was not significantly different among individuals with versus without a remitted SUD. There were no effects for comorbid SUD and distress-misery disorders. Finally, perceived DT was also significantly correlated within families, suggesting that it runs in families. Overall, results suggest that independent of neuroticism, low perceived DT is a familial vulnerability for distress (but not fear or substance use) disorders.

The role of intolerance of uncertainty in current and remitted internalizing and externalizing psychopathology

Intolerance of uncertainty (IU) is a putative key, transdiagnostic factor in internalizing psychopathologies. However, it is unclear if elevated levels of IU, as measured by the Intolerance of Uncertainty Scale, short form (IUS-12) and its subscales (prospective and inhibitory IU), persist into remission of internalizing psychopathologies (or particular types of internalizing psychopathologies; e.g., fear vs. distress-misery disorders). It is also unknown if IU is specifically characteristic of internalizing (vs. externalizing) psychopathology and whether this relationship is independent of neuroticism/negative affectivity (N/NA). A large community sample (n = 517) completed a diagnostic interview and self-report measures of IU and N/NA. Results indicated that, independent of N/NA, IU was elevated in current fear and distress/misery disorders, but not externalizing disorders. Individuals with remitted fear disorders also displayed significantly elevated levels of IU in comparison to healthy controls after adjusting for levels of N/NA. In terms of subscales, elevated levels of inhibitory IU, and not prospective IU, demonstrated more reliable relationships with internalizing psychopathologies. In summary, IU was more consistently related to fear disorders, demonstrated incremental validity over and above the effects of N/NA, and may be a key, transdiagnostic mechanism in fear disorders.

Mapping of Crowdsourcing in Health: Systematic Review

Background

Crowdsourcing involves obtaining ideas, needed services, or content by soliciting Web-based contributions from a crowd. The 4 types of crowdsourced tasks (problem solving, data processing, surveillance or monitoring, and surveying) can be applied in the 3 categories of health (promotion, research, and care).

Objective

This study aimed to map the different applications of crowdsourcing in health to assess the fields of health that are using crowdsourcing and the crowdsourced tasks used. We also describe the logistics of crowdsourcing and the characteristics of crowd workers.

Methods

MEDLINE, EMBASE, and ClinicalTrials.gov were searched for available reports from inception to March 30, 2016, with no restriction on language or publication status.

Results

We identified 202 relevant studies that used crowdsourcing, including 9 randomized controlled trials, of which only one had posted results at ClinicalTrials.gov. Crowdsourcing was used in health promotion (91/202, 45.0%), research (73/202, 36.1%), and care (38/202, 18.8%). The 4 most frequent areas of application were public health (67/202, 33.2%), psychiatry (32/202, 15.8%), surgery (22/202, 10.9%), and oncology (14/202, 6.9%). Half of the reports (99/202, 49.0%) referred to data processing, 34.6% (70/202) referred to surveying, 10.4% (21/202) referred to surveillance or monitoring, and 5.9% (12/202) referred to problem-solving. Labor market platforms (eg, Amazon Mechanical Turk) were used in most studies (190/202, 94%). The crowd workers’ characteristics were poorly reported, and crowdsourcing logistics were missing from two-thirds of the reports. When reported, the median size of the crowd was 424 (first and third quartiles: 167-802); crowd workers’ median age was 34 years (32-36). Crowd workers were mainly recruited nationally, particularly in the United States. For many studies (58.9%, 119/202), previous experience in crowdsourcing was required, and passing a qualification test or training was seldom needed (11.9% of studies; 24/202). For half of the studies, monetary incentives were mentioned, with mainly less than US $1 to perform the task. The time needed to perform the task was mostly less than 10 min (58.9% of studies; 119/202). Data quality validation was used in 54/202 studies (26.7%), mainly by attention check questions or by replicating the task with several crowd workers.

Conclusions

The use of crowdsourcing, which allows access to a large pool of participants as well as saving time in data collection, lowering costs, and speeding up innovations, is increasing in health promotion, research, and care. However, the description of crowdsourcing logistics and crowd workers’ characteristics is frequently missing in study reports and needs to be precisely reported to better interpret the study findings and replicate them.

A comparison and integration of structural models of depression and anxiety in a clinical sample: Support for and validation of the tri-level model

Prominent structural models of depression and anxiety arise from 2 traditions: (a) the tripartite/integrative hierarchical model based on symptom dimensions, and (b) the fear/anxious-misery model based on diagnostic comorbidity data. The tri-level model of depression and anxiety was developed to synthesize these structural models, postulating that narrow (disorder-specific), intermediate (fear and anxious-misery), and broad (general distress) structural factors are needed to most fully account for covariation among these symptoms. Although this model has received preliminary support (Prenoveau et al., 2010), the current study compares it with the above established models and seeks to validate the best-fitting structure. We evaluated the tri-level model and alternative structural models in a large clinical sample (N = 1,000) using bifactor analysis. In exploratory and confirmatory subsamples, the tri-level model provided a good fit to the data and each of the 3 levels (narrow, intermediate, and broad) accounted for substantial variance; this model provided a superior fit relative to more parsimonious competing structural models. Furthermore, impairment was independently associated with all 3 levels of the tri-level model, comorbidity was most closely linked to the broad tri-level dimensions, and the factors generally showed the expected convergent/discriminant associations with diagnoses. Results suggested several revisions to prior research: (a) worry may be best modeled at the broadest structural level, rather than as an indicator of anxious-misery or fear; (b) social interaction anxiety may belong with anxious-misery, rather than fear; and (c) obsessive-compulsive disorder is generally associated with fear disorders, but hoarding is associated with both fear and anxious-misery. (PsycINFO Database Record

Distinguishing Fear Versus Distress Symptomatology in Pediatric OCD

Prior research has identified OCD subtypes or "clusters" of symptoms that differentially relate to clinical features of the disorder. Given the high comorbidity between OCD and anxiety, OCD symptom clusters may more broadly associate with fear and/or distress internalizing constructs. This study examines fear and distress dimensions, including physical concerns (fear), separation anxiety (fear), perfectionism (distress), and anxious coping (distress), as predictors of previously empirically-derived OCD symptom clusters in a sample of 215 youth diagnosed with primary OCD (ages 7-17, mean age = 12.25). Self-reported separation fears predicted membership in Cluster 1 (aggressive, sexual, religious, somatic obsessions, and checking compulsions) while somatic/autonomic fears predicted membership in Cluster 2 (symmetry obsessions and ordering, counting, repeating compulsions). Results highlight the diversity of pediatric OCD symptoms and their differential association with fear, suggesting the need to carefully assess both OCD and global fear constructs that might be directly targeted in treatment.

Startle potentiation to uncertain threat as a psychophysiological indicator of fear-based psychopathology: An examination across multiple internalizing disorders

Heightened reactivity to uncertain threat (U-threat) is an important individual difference factor that may characterize fear-based internalizing psychopathologies (IPs) and distinguish them from distress/misery IPs. To date, however, the majority of existing research examining reactivity to U-threat has been within individuals with panic disorder and major depressive disorder (MDD) and no prior study has directly tested this hypothesis across multiple IPs. The current study therefore explored whether heightened reactivity to U-threat is a psychophysiological indicator of fear-based psychopathology across 5 groups: current (a) social anxiety disorder (SAD); (b) specific phobia (SP); (c) generalized anxiety disorder (GAD); (d) MDD; and (c) individuals with no history of psychopathology (controls). All 160 adults completed a well-validated threat-of-shock task designed to probe responses to predictable (P-) and U-threat. Startle eyeblink potentiation was recorded as an index of aversive arousal. Results indicated that individuals with SAD and SP evidenced greater startle potentiation to U-threat, but not P-threat, relative to individuals with GAD, MDD, and controls (who did not differ). The current findings, along with the prior panic disorder and MDD literature, suggest that heightened reactivity to U-threat is a psychophysiological indicator of fear-based disorders and could represent a neurobiological organizing principle for internalizing psychopathology. The findings also suggest that individuals with fear disorders generally display a hypersensitivity to uncertain aversive events, which could contribute to their psychopathology. (PsycINFO Database Record

Examination of a Bifactor Model of Obsessive-Compulsive Symptom Dimensions

Although obsessive-compulsive (OC) symptoms are observed along four dimensions (contamination, responsibility for harm, order/symmetry, and unacceptable thoughts), the structure of the dimensions remains unclear. The current study evaluated a bifactor model of OC symptoms among those with and without obsessive-compulsive disorder (OCD). The goals were (a) to evaluate if OC symptoms should be conceptualized as unidimensional or whether distinct dimensions should be interpreted and (b) to use structural equation modeling to examine the convergence of the OC dimensions above and beyond a general dimension with related criteria. Results revealed that a bifactor model fit the data well and that OC symptoms were influenced by a general dimension and by four dimensions. Measurement invariance of the bifactor model was also supported among those with and without OCD. However, the general OC dimension accounted for only half of the variability in OC symptoms, with the remaining variability accounted for by distinct dimensions. Despite evidence of multidimensionality, the dimensions were unreliable after covarying for the general OC dimension. However, the four dimensions did significantly converge with a latent OC spectrum factor above and beyond the general OC dimension. The implications of these findings for conceptualizing the structure of OCD are discussed.

The structure and intensity of self-reported autonomic arousal symptoms across anxiety disorders and obsessive-compulsive disorder

BACKGROUND

Heightened autonomic arousal symptoms (AAS) are assumed to be a central feature of anxiety disorders. However, it is unclear whether the magnitude and profile of AAS vary across anxiety disorders and whether heightened AAS characterises obsessive-compulsive disorder (OCD).

AIMS

We sought to determine whether the intensity and structure of AAS varied across anxiety disorders and OCD.

METHOD

A sample of 459 individuals with a primary anxiety disorder or OCD were administered the Symptom Checklist-90R. Nine items referring to prototypic AAS were included in a latent class analysis.

RESULTS

A 2-class solution (high and low AAS classes) best fitted the data. Participants comprising the high AAS class scored uniformly high across all assessed AAS symptoms. Older age and the presence of panic disorder, social anxiety disorder and generalized anxiety disorder predicted membership in the high AAS class. No OCD symptom dimension was significantly associated with membership in the high AAS class.

LIMITATION

AAS were assessed using a self-report measure and replication is needed using other methodologies.

CONCLUSIONS

These findings suggest that OCD may be sufficiently distinct from anxiety disorders and do not support subtyping of anxiety disorders on the basis of the predominant type of AAS. Therapeutic approaches that target AAS might best be applied in the treatment of panic disorder, social anxiety disorder and generalized anxiety disorder.