Comparative Effect of Collaborative Care, Pain Medication, and Duloxetine in the Treatment of Major Depressive Disorder and Comorbid (Sub)Chronic Pain: Results of an Exploratory Randomized, Placebo-Controlled, Multicenter Trial (CC:PAINDIP)

Four clinical profiles of adult outpatients with somatic Symptom Disorders and Related Disorders (SSRD). A latent class analysis

OBJECTIVE

To obtain more insight into the patterns of co-occurring symptoms, biomarkers and predictors in Somatic Symptom Disorders and Related Disorders (SSRD) and to identify subgroups with profiles that might allow for personalised treatment.

METHODS

Cross-sectional study design with Latent class analysis (LCA) to determine different subgroups in a cohort of 239 outpatients with SSRD in 3 steps: 1) building a latent class model; 2) assigning subjects to the latent classes that suited them best based on their posterior probability; 3) investigating the associations between these classes and personal characteristics such as age, gender, somatic comorbidity and general health perception.

RESULTS

Four classes with clinically relevant profiles were found. One with trauma plus elevated inflammation biomarkers, high somatic symptom levels, pain and comorbid depression and anxiety. One with pain plus elevated biomarkers, depression and anxiety. One with low IL-6 and hsCRP, mostly linked to Illness Anxiety. And one with high pain and high elevated biomarkers, but less probability of other factors, that occurred mostly in men. General health perception was lower in classes with elevated inflammation biomarkers.

CONCLUSIONS

The findings of this first study exploring latent classes in an SSRD sample corroborate the current DSM-5 SSD subclassification for pain and Illness Anxiety Disorder. There is scope to extend the current DSM-5 classification with a subclassification of SSD with trauma, and a subclassification with elevated IL6 or hsCRP, as relevant for developing new personalised treatments addressing trauma or SLI in SSRD. Further research is needed to explore this.

Type D Personality, Concomitant Depressive and Anxiety Disorders, and Treatment Outcomes in Somatic Symptom and Related Disorders: An Observational Longitudinal Cohort Study

Objective: To establish the prevalence of Type D personality in patients with somatic symptoms and related disorders and to evaluate the association of Type D personality with treatment outcomes. This study explores the effect of Type D personality and its two traits, negative affectivity (NA) and social inhibition (SI). Methods: In this longitudinal observational cohort study, we assessed the prevalence of Type D in 212 patients presenting themselves at a clinic in Tilburg, the Netherlands. We explored psychological and physical treatment outcomes of a multimodal treatment tailored to patient needs in relation to Type D scores. We explored the differences with regard to physical symptoms, anxiety, and depression. We also explored the differences between patients with and without Type D personality who completed treatment with regard to the baseline scores of physical symptoms, anxiety, and depression. We explored the association between Type D personality and treatment outcome using the traditional dichotomous method and the dimensional method (with main effects of NA and SI, and the interaction of NA × SI). Results: Of the 212 patients with Somatic Symptom and Related Disorders (SSRD), those with Type D personality (181: 61.8%) had experienced significantly higher levels of depression [t = 4.404, p < .001] and anxiety [t = 3.757, p < .001]. Of the 212, 187 patients completed treatment. Mean scores improved significantly for the whole patient group after treatment with regard to depression (p < .001), anxiety (p < .001), and physical symptoms (p < .001). At baseline, patients with Type D personality had significantly higher scores in anxiety [F = 15.707, p < .001] and depression [F = 19.392] than patients without Type D personality who completed treatment. After controlling for the high baseline scores with regard to physical symptoms, anxiety, or depression, only the effect of Type D personality on remission of anxiety was significant (OR = .33, p = 0.39). Neither NA and SI nor the interaction of NA × SI was associated with the treatment outcome. Conclusions: This study shows that Type D personality occurs frequently in patients with SSRD. Type D personality only decreases the probability of remission of anxiety as a treatment outcome, and both NA and SI play a role in this. Type D personality did not decrease remission either of physical symptoms or of depression. Hence, both NA and SI factors may be expressions of anxiety mostly in type D.

Loss of Microglia and Impaired Brain-Neurotrophic Factor Signaling Pathway in a Comorbid Model of Chronic Pain and Depression

Major depressive disorder (MDD) and chronic pain are two complex disorders that often coexist. The underlying basis for this comorbidity is unknown. In the current investigation, microglia and the brain-derived neurotrophic factor (BDNF)-cAMP response element-binding protein (CREB) pathway were investigated. A comorbidity model, with characteristics of both MDD and chronic pain, was developed by the administration of dextran sodium sulfate (DSS) and the induction of chronic unpredictable psychological stress (CUS). Mechanical threshold sensory testing and the visceromotor response (VMR) were employed to measure mechanical allodynia and visceral hypersensitivity, respectively. RT-qPCR and western blotting were used to assess mRNA and protein levels of ionized calcium-binding adaptor molecule 1 (Iba-1), nuclear factor-kappa B (NF-κB), nuclear factor of kappa light polypeptide gene enhancer in B-cells inhibitor, alpha (IκBa), BDNF, and CREB. In comorbid animals, mechanical allodynia and visceral hypersensitivities were significant with increased mRNA and protein levels for NF-κB-p65 and IκBa. Furthermore, the comorbid animals had deceased mRNA and protein levels for Iba-1, BDNF, and CREB as well as a reduced number and density of microglia in the medial prefrontal cortex (mPFC). These results together suggest that DSS and CUS can induce the comorbidities of chronic pain and depression-like behavior. The pathology of this comorbidity involves loss of microglia within the mPFC with subsequent activation of NF-κB-p65 and down-regulation of BDNF/p-CREB signaling.