Investigating the nature of co-occurring depression and anxiety: Comparing diagnostic and dimensional research approaches

BACKGROUND

Although approximately half of adults diagnosed with a depressive or anxiety disorder exhibit their simultaneous co-occurrence, traditional research has centered on single-target diagnoses, overlooking comorbidities within samples. In this article, we review and extend the literature that directly investigates co-occurring depression and anxiety, with the goal of shifting the focus from co-occurring diagnoses to symptom dimensions.

METHODS

First, we review studies that have directly compared psychobiological features (neural, neuroendocrine, autonomic) across depression, anxiety, and their co-occurrence, defined either categorically or dimensionally. Second, we analyze adults' diurnal cortisol secretion to examine the independent and interactive relations of continuously-assessed depressive and anxiety symptoms to neuroendocrine function.

RESULTS

Previous findings on the psychobiology of diagnostic co-occurrence are mixed. While nascent, evidence from dimensionally focused studies suggests that co-occurring levels of depressive and anxiety symptoms can interact with one another, as reflected in a distinct psychobiological profile for individuals with high levels of both symptom dimensions. Results of our analyses support this formulation: we found that depressive and anxiety symptom dimensions interacted consistently in their relation to the measures of diurnal cortisol.

LIMITATIONS

The illustrative sample was relatively small and included only women; future research should examine generalizability of these findings.

CONCLUSIONS

A dimensional approach to investigating the psychobiology of co-occurring depression and anxiety affords both conceptual and practical advantages. Simultaneously assessing depressive and anxiety symptom dimensions can efficiently capture their unique, shared, and interactive features, thereby identifying targets for intervention across a wide range of symptom presentations.

Intrinsic Connectivity Patterns of Task-Defined Brain Networks Allow Individual Prediction of Cognitive Symptom Dimension of Schizophrenia and Are Linked to Molecular Architecture

BACKGROUND

Despite the marked interindividual variability in the clinical presentation of schizophrenia, the extent to which individual dimensions of psychopathology relate to the functional variability in brain networks among patients remains unclear. Here, we address this question using network-based predictive modeling of individual psychopathology along 4 data-driven symptom dimensions. Follow-up analyses assess the molecular underpinnings of predictive networks by relating them to neurotransmitter-receptor distribution patterns.

METHODS

We investigated resting-state functional magnetic resonance imaging data from 147 patients with schizophrenia recruited at 7 sites. Individual expression along negative, positive, affective, and cognitive symptom dimensions was predicted using a relevance vector machine based on functional connectivity within 17 meta-analytic task networks following repeated 10-fold cross-validation and leave-one-site-out analyses. Results were validated in an independent sample. Networks robustly predicting individual symptom dimensions were spatially correlated with density maps of 9 receptors/transporters from prior molecular imaging in healthy populations.

RESULTS

Tenfold and leave-one-site-out analyses revealed 5 predictive network-symptom associations. Connectivity within theory of mind, cognitive reappraisal, and mirror neuron networks predicted negative, positive, and affective symptom dimensions, respectively. Cognitive dimension was predicted by theory of mind and socioaffective default networks. Importantly, these predictions generalized to the independent sample. Intriguingly, these two networks were positively associated with D₁ receptor and serotonin reuptake transporter densities as well as dopamine synthesis capacity.

CONCLUSIONS

We revealed a robust association between intrinsic functional connectivity within networks for socioaffective processes and the cognitive dimension of psychopathology. By investigating the molecular architecture, this work links dopaminergic and serotonergic systems with the functional topography of brain networks underlying cognitive symptoms in schizophrenia.

Relationship between early maladaptive schemas and symptom dimensions in patients with obsessive-compulsive disorder

The aims of this study were to evaluate early maladaptive schemas (EMSs) of patients with obsessive-compulsive disorder (OCD) and to clarify relationships between particular EMSs and the five factor-analyzed symptom dimensions and other clinical variables. Fifty-seven patients with OCD and 70 normal controls completed the Young Schema Questionnaire, the Yale-Brown Obsessive Compulsive Scale (Y-BOCS), the Y-BOCS symptom checklist, and the Beck Depression Inventory. Patients with OCD had significantly higher scores for schema related to defectiveness/shame, social isolation/alienation, and failure than did normal controls. Among the five OCD symptom dimensions, the sexual/religious dimension was only significantly correlated with two schemas of vulnerability to harm or illness and enmeshment/undeveloped self. These two schemas were significant predictors of the sexual/religious dimension, accounting for 33% of the total variance in this dimension. Any EMSs in patients with OCD were not related to clinical variables such as severity of OCD and duration of illness. These findings may constitute evidence to improve our understandings of OCD from a perspective of schema theory.

Symptom dimensions in obsessive-compulsive disorder as predictors of neurobiology and treatment response

Purpose of review

Specific symptom dimensions of obsessive-compulsive disorder (OCD) have been suggested as an approach to reduce the heterogeneity of obsessive-compulsive disorder, predict treatment outcome, and relate to brain structure and function. Here, we review studies addressing these issues.

Recent findings

The contamination and symmetry/ordering dimensions have not been reliably associated with treatment outcome. Some studies found that greater severity of sexual/aggressive/religious symptoms predicted a worse outcome after cognitive behavioral therapy (CBT) and a better outcome after serotonin reuptake inhibitors (SRIs). Contamination symptoms have been related to increased amygdala and insula activation in a few studies, while sexual/aggressive/religious symptoms have also been related to more pronounced alterations in the function and structure of the amygdala. Increased pre-treatment limbic responsiveness has been related to better outcomes of CBT, but most imaging studies show important limitations and replication in large-scale studies is needed. We review possible reasons for the strong limbic involvement of the amygdala in patients with more sexual/aggressive/religious symptoms, in relation to their sensitivity to CBT.

Summary

Symptom dimensions may predict treatment outcome, and patients with sexual/religious/aggressive symptoms are at a greater risk of not starting or delaying treatment. This is likely partly due to more shame and perceived immorality which is also related to stronger amygdala response. Competently delivered CBT is likely to help these patients improve to the same degree as patients with other symptoms.

Association between hippocampus volume and symptom profiles in obsessive-compulsive disorder

Background

The hippocampus has recently been identified to play a key role in the pathophysiology of adult obsessive-compulsive disorder (OCD). Surprisingly, there is only limited evidence regarding the potential relationships with symptom dimensions. Due to the heterogeneity of symptoms in OCD, we aimed at further examining, whether hippocampal volume differences might be related to symptom profiles instead of single symptom dimensions.

Methods

In order to find out more about the potential association between clinical symptom profiles and alterations in hippocampal volume we categorized a large sample of OCD patients (N = 66) into distinct symptom profile groups using K-means clustering. In addition, hippocampal volumes of the different symptom profile groups were compared with hippocampal volumes in a sample of 66 healthy controls.

Results

We found significant differences in hippocampal volume between the different symptom profile groups which remained significant after correcting for age, sex, total intracranial volume, OCI-total score, depression, medication, disease duration and scanner. The patient group characterized by overall lower symptom scores and without high symptom severity in any specific domain showed the highest hippocampal volume. Finally, the comparison with healthy controls demonstrated significantly lower hippocampal volumes in those patients whose symptom profile was characterized by a high severity of ordering and checking symptoms.

Conclusions

Present results provide further confirmation for alterations in hippocampus structure in OCD and suggest that symptom profiles which take into account the multi-symptomatic character of the disorder should be given greater attention in this context.

•

Different symptom profiles are associated with differences in hippocampus volume.

•

This effect seems to be independent of other clinical parameters.

•

Symptom interrelations seem to link structural alterations and psychopathology.

Cognitive vulnerability differentially predicts symptom dimensions of depression

BACKGROUND

We examined the association of cognitive vulnerability to depression with changes in homogeneous measures of depressive symptoms.

METHODS

Baseline and 1-year follow-up data were obtained from 2981 participants of the Netherlands study of depression and anxiety. Multivariate regression analyses were carried out on cognitive reactivity, locus of control and implicit and explicit self-depressive associations in combination with negative life events. The purpose of this analysis was to predict changes on the mood/cognition and anxiety/arousal subscales of the inventory of depressive symptomatology - self report.

RESULTS

Cognitive reactivity, locus of control and explicit self-depressive associations were independently associated with changes in depressive symptoms after adjustment for covariates and baseline severity (all p<0.01). Negative life-events interacted with cognitive vulnerability to depression to predict depressive symptoms. Locus of control (b1=0.16, SE=0.02, η(2)=0.01; b2=0.10, SE=0.02, η(2)=0.004, F=8.69, p<0.01) and explicit self-depressive associations (b1=0.10, SE=0.03, η(2)=0.02; b2=0.02, SE=0.04, F=7.50, p<0.01) were more strongly associated with the cognitive (b1) than the somatic (b2) symptom dimension of depression.

LIMITATIONS

The study sample is over-inclusive of depressed patients. Therefore it might be problematic generalizing the findings to the general population.

CONCLUSION

Cognitive etiological factors may play a role in a "cognitive" subtype of depression. The findings strengthen the notion that homogeneous measures of depressive symptoms enable a greater degree of discrimination between subtypes than a multidimensional conception of depression.

BDNF gene and obsessive compulsive disorder risk, symptom dimensions and treatment response

AIM

Genetic etiology of Obsessive Compulsive Disorder (OCD) has been investigated extensively, with mixed results across candidate gene studies. The dimensional subtypes of OCD are shown to better correlate with brain imaging endophenotypes and thus could potentially enhance the power of genetic association. In this study, we perform a case control analysis of association of a single nucleotide polymorphism rs6265(Val66Met) in Brain Derived Neurotrophic Factor gene, that has been previously implicated in a variety of psychiatric syndromes, and examine its association with symptom dimensions of OCD.

METHODS

Individuals diagnosed to have OCD (n=377) and controls (n=449) of South Indian origin were genotyped for polymorphism rs6265 (196G/A, Val66Met). Detailed phenotypic assessment of the cases were carried out in the cases using structured instruments. The genotypic association was tested for clinical variables such as age of onset, gender, family history, co-morbidity, treatment response, and factor analyzed OCD symptom dimensions.

RESULTS

The allele 'A' frequency was found to be significantly higher in the controls, as compared to cases suggesting a protective effect. The contamination/washing symptom dimension score was significantly lower in carriers of 'A' allele which remained significant even after testing for confounding effects on linear regression.

CONCLUSIONS

Our results support findings from previous studies on a possible protective effect of the 'Met' allele at the Val66Met locus in OCD. Its association with lower scores on the contamination/washing dimension is a novel finding of this study.

Neurocircuitry associated with symptom dimensions at baseline and with change in borderline personality disorder

Borderline personality disorder (BPD) is a serious illness associated with chronic suffering and self-injurious behavior. Parsing the relationships between specific symptom domains and their underlying biological mechanisms may help us further understand the neural circuits implicated in these symptoms and how they might be amenable to change with treatment. This study examines the association between symptom dimensions (Affective Disturbance, Cognitive Disturbance, Disturbed Relationships, and Impulsivity) and amygdala resting-state functional connectivity (RSFC) in a sample of adults with BPD (n = 18). We also explored the relationships between change in symptom dimensions and change in amygdala RSFC in a subset of this sample (n = 13) following 8 weeks of quetiapine or placebo. At baseline, higher impulsivity was associated with increased positive RSFC between right amygdala and left hippocampus. There were no significant differences in neural change between treatment groups. Improvement in cognitive disturbance was associated with increased positive RSFC between left amygdala and temporal fusiform and parahippocampal gyri. Improvement in disturbed relationships was associated with increased negative RSFC between right amygdala and frontal pole. These results support that specific dimensions of BPD are associated with specific neural connectivity patterns at baseline and with change, which may represent neural treatment targets.

A clinical comparison of schizophrenia with and without pre-onset cannabis use disorder: a retrospective cohort study using categorical and dimensional approaches

BACKGROUND

A high prevalence of cannabis use disorder has been reported in subjects suffering from schizophrenia, fuelling intense debate about whether schizophrenia with pre-onset cannabis use disorder may be a distinct entity with specific features or whether cannabis use disorder can precipitate schizophrenia in genetically vulnerable subjects.

METHODS

We retrospectively assessed schizophrenia subjects with and without pre-onset cannabis use disorder on the basis of their clinical features, assessed categorically and dimensionally with the operational criteria checklist for psychotic illnesses (OCCPI). We also investigated whether the two groups could be differentiated on the basis of a history of psychiatric disorders in first-degree relatives. A principal component factor analysis of the OCCPI items was used to identify specific symptom dimensions. The relationships between symptom dimensions and cannabis status were analysed by point-biserial correlation analysis to control for sex and age at time of the assessment and illness duration.

RESULTS

One hundred and seventy-one subjects with a diagnosis of schizophrenia were included. Among them, forty-one patients (18.2 % of the sample) had a cannabis use disorder before or at the time of the onset of schizophrenia. We found similar results in symptoms patterns or family history between patients with and without pre-onset cannabis use disorder.

CONCLUSIONS

Our results clearly argue against cannabis-associated schizophrenia being a relevant distinct clinical entity of schizophrenia with specific features.

Understanding trajectories of underlying dimensions of posttraumatic psychopathology

BACKGROUND

Research suggests four modal trajectories of psychological symptoms after traumatic injury: Resilient, Chronic, Delayed Onset, Recovery. However, most studies focus on symptoms of psychiatric disorders (e.g., posttraumatic stress disorder, depression), which are limited by heterogeneity and symptom overlap. We examined trajectories of cross-cutting posttraumatic symptom dimensions following traumatic injury and predictors of trajectory membership.

METHODS

In this longitudinal study of 427 predominantly Hispanic/Latino traumatic injury survivors, posttraumatic psychopathology symptoms were assessed during hospitalization and approximately one and five months post-trauma. Using latent class growth analysis, we estimated trajectories of several posttraumatic symptom dimensions: re-experiencing, avoidance, anxious arousal, numbing, dysphoric arousal, loss, and threat. We then examined sociodemographic and trauma-related characteristics (measured during hospitalization) as predictors of trajectory membership for each dimension.

RESULTS

Four trajectories (Resilient, Chronic, Delayed Onset, Recovery) emerged for all dimensions except loss and threat, which manifested three trajectories (Resilient, Chronic, Delayed Onset). Across dimensions, membership in the Chronic (vs. Resilient) trajectory was consistently predicted by unemployment (7 of 7 dimensions), followed by older age (3/7), female sex (3/7), and assaultive trauma (2/7). For several dimensions, unemployment also distinguished between participants who presented with similar symptom levels days after trauma, but then diverged over time.

LIMITATIONS

Measures of posttraumatic symptom dimension constructs differed across assessments.

CONCLUSIONS

This study provides evidence of distinct trajectories across transdiagnostic symptom dimensions after traumatic injury. Employment status emerged as the most important predictor of trajectory membership. Research is needed to better understand the etiologies and consequences of these posttraumatic symptom dimension trajectories.

Is Acceptance and Commitment Therapy Effective for Any Obsessive-Compulsive Symptom Dimensions?

OBJECTIVE

Acceptance and commitment therapy (ACT) has been recently introduced for treating obsessive-compulsive disorder (OCD). Although there are data supporting the efficacy of ACT, only few studies have investigated the effectiveness of ACT against any obsessivecompulsive (OC) symptom dimension or a specific dimension alone.

METHODS

In total, 64 patients with OCD received an 8-session ACT group program. All measures were evaluated before and after treatment. The Dimensional Obsessive-Compulsive Scale was used to assess OCD severity across the four empirically supported symptom dimensions (i.e., contamination, responsibility for harm, unacceptable thoughts, and symmetry). ACT processes were evaluated using the Acceptance and Action Questionnaire-II (AAQ-II), Acceptance and Action Questionnaire for Obsessions and Compulsions (AAQOC), and Cognitive Fusion Questionnaire.

RESULTS

After an 8-week program, there were significant reductions in all four OC symptom dimensions after ACT. The unacceptable thoughts and contamination domains had medium effect size. The responsibility for harm and symmetry dimensions had small effect size. The unacceptable thoughts dimension was significantly correlated with all ACT process measures. The symmetry dimension was significantly correlated with AAQ-OC and AAQ-II scores while the responsibility for harm dimension was correlated with AAQ-II alone. However, the contamination dimension was not associated with any process measures.

CONCLUSION

ACT may be effective for managing all four symptom dimensions with small to moderate effect size. Moreover, depending on the symptom dimension, there may be different relationship patterns between symptom reduction and changes in ACT processes.