Cytokine production capacity in depression and anxiety

Correlation between systemic inflammatory response and quality of life in patients with chronic rhinosinusitis

BACKGROUND

Local sinonasal inflammation resulting from altered T-cell immune signaling is a contributor to the pathogenesis of chronic rhinosinusitis (CRS). CRS patients experience negative impacts on quality of life (QOL) and suffer from comorbidities linked to systemic inflammation. However, systemic inflammatory profiling to evaluate the association between systemic inflammation and QOL in CRS has not been performed. Our objectives were to compare local and systemic inflammatory gene expression in patients with CRS to determine if systemic markers of inflammation associate with disease severity and disease-specific QOL.

METHODS

A prospective observational study was conducted comparing 16 patients with CRS to 10 controls. Inflammatory gene expression in the anterior ethmoid tissues and peripheral blood of patients was measured using multiplex gene expression analysis and correlated to disease severity (computed tomography and nasal endoscopy) and disease-specific QOL (22-item Sino-Nasal Outcome Test [SNOT-22] and Rhinosinusitis Disability Index) using linear regression analyses.

RESULTS

Patients with CRS showed significant increases in the expression of ctla4 and jak1 in sinonasal tissue and blood (p < 0.05), whereas the gene expression of hla-dqa1, hla-dqb1, and dusp4 was significantly decreased in patients with CRS compared to controls (p < 0.05). Soluble and local ctla4 and jak1 showed a significant positive correlation with clinical markers of disease severity and disease-specific QOL (p < 0.05).

CONCLUSION

Local and systemic gene expression involved in T-cell immune signaling was found to be significantly altered in the blood and sinonasal tissues of patients with CRS compared to controls and significantly correlated to disease severity and QOL in patients with CRS.

Dietary Inflammatory Potential and the Risk of Incident Depression in Adults: A Systematic Review

Diet is proposed to have a stimulatory or preventative influence on mental health and the risk of depressive symptoms, given that the diet can have either a pro- or an anti-inflammatory effect. This study aimed to collate the relation between dietary inflammatory potential and the risk of depression. PubMed, Google Scholar, ScienceDirect, and Scopus databases, as well as Google were searched for articles published at any date until May 2018. Original English-language articles involving human participants and studies that investigated the association between dietary inflammatory potential and the risk of developing depression were included. Duplicated and irrelevant reports were screened out and data were extracted during critical analysis. Our search method initially identified 173 articles, of which 48 remained after duplicates had been removed. Thirteen articles were screened and identified as being relevant to the study topic. After critical analysis, 12 articles were included in the final analysis. All of the articles but 1 reported that higher dietary inflammatory index (DII) is associated with a higher risk of developing depression. Three studies indicated that DII was positively correlated with circulating inflammatory markers; however, in these studies increased concentrations of circulating inflammatory markers did not predict the diet-depression relation. Low literacy, unhealthy lifestyle, nutritional status, marital status, and age were potent contributory factors to whether or not a diet with inflammatory potential was consumed. These findings support the hypothesis that the DII is an appropriate tool for measuring dietary inflammatory potential, and reinforce the role of diets with inflammatory potential in the pathophysiology of depression.

Inflammation in older subjects with early- and late-onset depression in the NESDO study: a cross-sectional and longitudinal case-only design

OBJECTIVE

Different biological mechanisms may underlie depression beginning in early life (early-onset) and depression beginning later in life (late-onset). Although the relation between inflammation and depression has been studied extensively, the distinct role of inflammation in early and late-onset depression in older patients has not been addressed before. In the cross-sectional part of this study, we explored differences in levels of circulating inflammatory markers and cytokine levels in lipopolysaccharide (LPS) stimulated whole blood between older subjects with a late-life onset depression (≥60 years) and older subjects with an early-onset depression (<60 years). Secondly, in a 2-year follow-up study, we examined if circulating and stimulated inflammatory markers influenced the change in Inventory of Depressive Symptomatology (IDS) scores, and if this relation was different for early- and late-onset depression.

METHODS

The study was part of the Netherlands Study of Depression in Older Persons (NESDO). We included 350 patients, all aged 60 and older, with a depressive episode in the previous 6 months: 119 with a late-onset depression and 231 with an early-onset depression. Blood samples were collected and CRP, IL-6, NGAL, GDF15, and, LPS plasma levels were determined and whole blood was LPS stimulated and cytokine levels IL-1β, IL-6, TNFα, IFNγ, IL-10, and IL-1 receptor antagonist (IL-1ra) were determined.

RESULTS

After adjustment for demographics, health indicators, and medication use, increased plasma CRP levels were more strongly associated with late-onset depression than early-onset depression (OR [95% CI]: 1.43 [1.05-1.94]). In the longitudinal analyses, higher circulating IL-6 levels were associated with a significantly slower decline in IDS scores in the crude and the adjusted models (p ≤ 0.027). This relation was not different between late- and early-onset depression. Other circulating and stimulated inflammatory markers were not associated with late- and/or early-onset depression.

CONCLUSIONS

This study provides preliminary evidence that low-grade inflammation is more strongly associated with late-onset than early-onset depression in older adults, suggesting a distinct inflammatory etiology for late-onset depression. Cytokine production capacity did not distinguish between early- and late-onset depression.

Anhedonia as a clinical correlate of inflammation in adolescents across psychiatric conditions

Objectives: Peripheral inflammation has been associated with multiple psychiatric disorders, particularly with depression. However, findings remain inconsistent and unreproducible, most likely due to the disorder's heterogeneity in phenotypic presentation. Therefore, in the present study, in an effort to account for inter-individual differences in symptom severity, we utilised a dimensional approach to assess the relationships between a broad panel of inflammatory cytokines and key psychiatric symptoms (i.e. depression, anhedonia, anxiety, fatigue and suicidality) in adolescents across psychiatric disorders. We hypothesised that only anhedonia (reflecting deficits of reward function) will be associated with inflammation.Methods: Participants were 54 psychotropic medication-free adolescents with diverse psychiatric conditions and 22 healthy control (HC) adolescents, aged 12-20. We measured 41 cytokines after in vitro lipopolysaccharide stimulation. Mann-Whitney U and Spearman correlation tests examined group comparison and associations, respectively, while accounting for multiple comparisons and confounds, including depression severity adolescent.Results: There were no group differences in cytokine levels. However, as hypothesised, within the psychiatric group, only anhedonia was associated with 19 cytokines, including haematopoietic growth factors, chemokines, pro-inflammatory cytokines, and anti-inflammatory cytokines.Conclusions: Our findings suggest that general inflammation may induce reward dysfunction, which plays a salient role across psychiatric conditions, rather than be specific to one categorical psychiatric disorder.

Sex differences in how inflammation affects behavior: What we can learn from experimental inflammatory models in humans

Human models demonstrate that experimental activation of the innate immune system has profound effects on brain activation and behavior, inducing fatigue, worsened mood and pain sensitivity. It has been proposed that inflammation is a mechanism involved in the etiology and maintenance of depression, chronic pain and long-term fatigue. These diseases show a strong female overrepresentation, suggesting that a better understanding of sex differences in how inflammation drives behavior could help the development of individualized treatment interventions. For this purpose, we here review sex differences in studies using experimental inflammatory models to investigate changes in brain activity and behavior. We suggest a model in which inflammation accentuates sex differences in brain networks and pre-existing vulnerability factors. This effect could render women more vulnerable to the detrimental effects of immune-to-brain communication over time. We call for systematic and large scale investigations of vulnerability factors for women in the behavioral response to inflammation.

Difference in proinflammatory cytokines produced by monocytes between patients with major depressive disorder and healthy controls

BACKGROUND

Immune activation and suppression in patients with major depressive disorders (MDD) have been both reported in different studies. We assume that these findings may indicate innate immunological tolerance in MDD, with subclinical elevated level of proinflammatory cytokines and the decrease in innate immune response while encountering pathogens.

METHODS

Peripheral monocytes of 50 untreated patients with MDD and 40 healthy controls were isolated and cultured, with or without 10 ng/ml lipopolysacchride (LPS) for 6 h (6 h, LPS+/-), and with LPS for 18 h (18, LPS+). The cell culture supernatants were collected to measure concentrations of tumor necrosis factor-alpha (TNF-α), interleukin 6 (IL-6), and interleukin 1 beta (IL-1β).

RESULTS

The baseline concentrations of IL-6 and IL-1β (6 h, LPS-) were significantly higher in the MDD group than those in the control group. There was no significant difference of TNF-α between the two groups. The fold changes of LPS-induced secretion of IL-6 and TNF-α from monocytes cultured for 6 and 18 h were all lower in the patient groups, and that was true for IL-1β as monocytes cultured for 18 h.

LIMITATIONS

Given the gap between the results of in vitro experiments and the actual response that happens in vivo when the immune system encounters pathogens from the external world, future research should include in vivo methods to test the results of the current study.

CONCLUSIONS

Patients with MDD may have subclinical inflammation during a depressive episode, and the reduced response to LPS in monocytes indicates innate immunological tolerance.

Relationships between obstructive sleep apnea and anxiety

PURPOSE OF REVIEW

To summarize recent research investigating the interaction between obstructive sleep apnea (OSA) and anxiety, and contextualize their bidirectional relationship.

RECENT FINDINGS

Recent investigations corroborate the bidirectional relationship between sleep-disordered breathing (SDB) and anxiety, evaluate the etiological and clinical manifestations through different mechanisms, and provide insight into clinical implications of this interaction. Much of the literature about anxiety as it relates to SDB is from small samples, using different tools of symptom measurement that are often subjectively quantified. The objective severity of OSA does not appear to be associated with subjectively reported sleepiness and fatigue, whereas physiological manifestations of anxiety are associated with the severity of subjective symptoms reported. Recent findings support that women are more likely to have comorbid SDB and anxiety than men. SDB may precipitate and perpetuate anxiety, whereas anxiety in OSA negatively impacts quality-of-life. Treating SDB may improve anxiety symptoms, whereas anxiety symptoms can be an obstacle and deterrent to appropriate treatment.

SUMMARY

The interaction between anxiety and SDB is still poorly elucidated. Being aware of the clinical associations, risk factors, and treatment implications for SDB as related to anxiety disorders in different populations can help clinicians with the diagnosis and management of both SDB and anxiety.

Assessment of Translocator Protein Density, as Marker of Neuroinflammation, in Major Depressive Disorder: A Pilot, Multicenter, Comparative, Controlled, Brain PET Study (INFLADEP Study)

Background: Major depressive disorder (MDD) is a serious public health problem with high lifetime prevalence (4.4-20%) in the general population. The monoamine hypothesis is the most widespread etiological theory of MDD. Also, recent scientific data has emphasized the importance of immuno-inflammatory pathways in the pathophysiology of MDD. The lack of data on the magnitude of brain neuroinflammation in MDD is the main limitation of this inflammatory hypothesis. Our team has previously demonstrated the relevance of [18F] DPA-714 as a neuroinflammation biomarker in humans. We formulated the following hypotheses for the current study: (i) Neuroinflammation in MDD can be measured by [18F] DPA-714; (ii) its levels are associated with clinical severity; (iii) it is accompanied by anatomical and functional alterations within the frontal-subcortical circuits; (iv) it is a marker of treatment resistance. Methods: Depressed patients will be recruited throughout 4 centers (Bordeaux, Montpellier, Tours, and Toulouse) of the French network from 13 expert centers for resistant depression. The patient population will be divided into 3 groups: (i) experimental group-patients with current MDD (n = 20), (ii) remitted depressed group-patients in remission but still being treated (n = 20); and, (iii) control group without any history of MDD (n = 20). The primary objective will be to compare PET data (i.e., distribution pattern of neuroinflammation) between the currently depressed group and the control group. Secondary objectives will be to: (i) compare neuroinflammation across groups (currently depressed group vs. remitted depressed group vs. control group); (ii) correlate neuroinflammation with clinical severity across groups; (iii) correlate neuroinflammation with MRI parameters for structural and functional integrity across groups; (iv) correlate neuroinflammation and peripheral markers of inflammation across groups. Discussion: This study will assess the effects of antidepressants on neuroinflammation as well as its role in the treatment response. It will contribute to clarify the putative relationships between neuroinflammation quantified by brain neuroimaging techniques and peripheral markers of inflammation. Lastly, it is expected to open innovative and promising therapeutic perspectives based on anti-inflammatory strategies for the management of treatment-resistant forms of MDD commonly seen in clinical practice. Clinical trial registration (reference: NCT03314155): https://www.clinicaltrials.gov/ct2/show/NCT03314155?term=neuroinflammation&cond=depression&cntry=FR&rank=1.

The role of anxious distress in immune dysregulation in patients with major depressive disorder

Although depression with anxious distress appears to be a clinically relevant subtype of major depressive disorder (MDD), whether it involves specific pathophysiology remains unclear. Inflammation has been implicated, but not comprehensively studied. We examined within a large MDD sample whether anxious distress and related anxiety features are associated with differential basal inflammation and innate cytokine production capacity. Data are from 1078 MDD patients from the Netherlands Study of Depression and Anxiety. In addition to the DSM-5 anxious distress specifier, we studied various dimensional anxiety scales (e.g. Inventory of Depressive Symptomatology anxiety arousal subscale [IDS-AA], Beck Anxiety Inventory [BAI], Mood and Anxiety Symptoms Questionnaire Anxious Arousal scale [MASQ-AA]). The specifier was constructed using five self-report items from the IDS and BAI. Basal inflammatory markers included C-reactive protein (CRP), interleukin (IL)-6 and tumor necrosis factor (TNF)-α. Innate production capacity was assessed by 13 lipopolysaccharide (LPS)-stimulated inflammatory markers. Basal and LPS-stimulated inflammation index scores were created. Basal inflammation was not associated with anxious distress (prevalence = 54.3%) in MDD patients, except for a modest positive association for BAI score. However, anxious distress was associated with higher LPS-stimulated levels (interferon-γ, IL-6, monocyte chemotactic protein (MCP)-1, macrophage inflammatory protein (MIP)-1α, matrix metalloproteinase (MMP)-2, TNF-α, LPS-stimulated index). Other anxiety indicators (anxious distress specifier score, BAI, MASQ-AA) were also associated with increased innate production capacity. Within a large MDD sample, the anxious distress specifier was associated with increased innate cytokine production capacity but not with basal inflammation. Results from dimensional anxiety indicators largely confirm these results. These findings provide new insight into the pathophysiology of anxious depression.

Modulating Neuroinflammation to Treat Neuropsychiatric Disorders

Neuroinflammation is recognised as one of the potential mechanisms mediating the onset of a broad range of psychiatric disorders and may contribute to nonresponsiveness to current therapies. Both preclinical and clinical studies have indicated that aberrant inflammatory responses can result in altered behavioral responses and cognitive deficits. In this review, we discuss the role of inflammation in the pathogenesis of neuropsychiatric disorders and ask the question if certain genetic copy-number variants (CNVs) associated with psychiatric disorders might play a role in modulating inflammation. Furthermore, we detail some of the potential treatment strategies for psychiatric disorders that may operate by altering inflammatory responses.

The effect of ethanolic extract of Thymus kotschyanus on cancer cell growth in vitro and depression-like behavior in the mouse

Cancer and depression are known as two of the most debilitating disease and disorder increasing evidence suggest an urgent need for new therapeutic agents with lower toxicity and high efficacy. Some Thyme species extracts have remarkably been shown to positively affect depression and cancer cells. In the present study, we investigated the effect of Thymus kotschyanus on depression and cancer cells. To this end, in experiment 1, NMRI mice were treated orally with the ethanolic extract of T. kotschyanus (50, 150 and 250 mg/ml) for seven days and then depression-like behavior was measured by Forced Swim Test (FST) and Tail Suspension Test (TST). In experiment 2, the pharmacological effect of the extract on the lung (A549) and cervical (Hela) cancer cell lines was also evaluated by MTT (3-(4,5-Dimethylthiazol-2-Yl)-2,5-Diphenyltetrazolium Bromide) in various concentration_(10, 5, 2.5, 1.25, 0.63, 0.31, 0.15 and 0.08 mg/ml). The results indicated that T. kotschyanus extract treatment (150 and 250 mg/kg) decreased depression-like behavior in the FST and TST tests in adult mice. Moreover, the treatment inhibited cancer cell growth and viability in a dose and time-dependent manner. Collectively these findings suggest that T. kotschyanus have antidepressant and anticancer effects.

Oral application of carbon nanofibers in rats increases blood concentration of IL6 and IL10 and decreases locomotor activity

Carbon nanofibers (CNF) are versatile nanomaterials that are widely used in various fields of science and technology. As a consequence, animals as well as humans may be exposed to such compounds via different routes. We hypothesized that oral intake of CNF will lead to an inflammatory reaction and consequently induce behavioral impairments. To address this issue, rats were fed with 500mg/kgCNF for 14days and their locomotor activity, emotional status and cognition were quantified by testing the animals in an open field set-up, elevated plus maze and in the universal problem solving box which provides information about motivation and cognition. The behavioral tests were performed 3 times within 10days. At the end of the experiment, blood samples were collected and the plasma concentrations of IL-6, IL-8, IL-1β, IL-10 and IL-18 were measured. Our results demonstrated an inflammatory reaction determined by a significantly elevated IL-6 concentration. This, however, was counteracted by an even more pronounced increase in IL-10. The behavioral effects were restricted mainly to a decrease in locomotor activity which was significant in the open field test, as well as the elevated plus maze. Other parameters indicative of cognitive performance were not influenced and also the emotional status was largely unaffected. In conclusion, our results revealed that oral intake of 500mg/kgCNF induced some adverse effects, which, however, can be still partially compensated by the organism.

Diverse action of lipoteichoic acid and lipopolysaccharide on neuroinflammation, blood-brain barrier disruption, and anxiety in mice

Microbial metabolites are known to affect immune system, brain, and behavior via activation of pattern recognition receptors such as Toll-like receptor 4 (TLR4). Unlike the effect of the TLR4 agonist lipopolysaccharide (LPS), the role of other TLR agonists in immune-brain communication is insufficiently understood. We therefore hypothesized that the TLR2 agonist lipoteichoic acid (LTA) causes immune activation in the periphery and brain, stimulates the hypothalamic-pituitary-adrenal (HPA) axis and has an adverse effect on blood-brain barrier (BBB) and emotional behavior. Since LTA preparations may be contaminated by LPS, an extract of LTA (LTAextract), purified LTA (LTApure), and pure LPS (LPSultrapure) were compared with each other in their effects on molecular and behavioral parameters 3h after intraperitoneal (i.p.) injection to male C57BL/6N mice. The LTAextract (20mg/kg) induced anxiety-related behavior in the open field test, enhanced the circulating levels of particular cytokines and the cerebral expression of cytokine mRNA, and blunted the cerebral expression of tight junction protein mRNA. A dose of LPSultrapure matching the amount of endotoxin/LPS contaminating the LTAextract reproduced several of the molecular and behavioral effects of LTAextract. LTApure (20mg/kg) increased plasma levels of tumor necrosis factor-α (TNF-α), interleukin-6 and interferon-γ, and enhanced the transcription of TNF-α, interleukin-1β and other cytokines in the amygdala and prefrontal cortex. These neuroinflammatory effects of LTApure were associated with transcriptional down-regulation of tight junction-associated proteins (claudin 5, occludin) in the brain. LTApure also enhanced circulating corticosterone, but failed to alter locomotor and anxiety-related behavior in the open field test. These data disclose that TLR2 agonism by LTA causes peripheral immune activation and initiates neuroinflammatory processes in the brain that are associated with down-regulation of BBB components and activation of the HPA axis, although emotional behavior (anxiety) is not affected. The results obtained with an LTA preparation contaminated with LPS hint at a facilitatory interaction between TLR2 and TLR4, the adverse impact of which on long-term neuroinflammation, disruption of the BBB and mental health warrants further analysis.

Etiology and Treatment of Pain and Psychosocial Issues in Patients With Inflammatory Bowel Diseases

There is increasing evidence that brain-gut interactions are altered during development of inflammatory bowel diseases (IBDs). Understanding the relationship between the neurobiology, psychological symptoms, and social ramifications of IBD can guide comprehensive care for the whole patient. The most common psychological conditions in patients with IBD are chronic abdominal pain, anxiety, and depression. We review the evidence-based data and rates of these conditions and their respective relationship to IBD and the diagnostic approaches to identify patients with these conditions. Different treatment options for pain and psychosocial conditions are discussed, and new models of team-based IBD care are introduced. Providing the health care provider with tools to diagnose and manage psychological conditions in patients with Crohn's disease or ulcerative colitis is necessary for their total care and should be part of quality-improvement initiatives.

Cytokine profile and maternal depression and anxiety symptoms in mid-pregnancy-the FinnBrain Birth Cohort Study

Maternal prenatal psychological symptoms are associated with child health outcomes, e.g., atopic diseases. Altered prenatal functioning of the immune system is a potential mechanism linking maternal symptoms with child health. Research on prenatal distress and cytokines is warranted. The study population comprised consecutive N = 139 women from a general population-based FinnBrain Birth Cohort Study. Standardized questionnaires for depressive, overall anxiety, and pregnancy-related anxiety symptoms were used. Serum concentrations of selected cytokines were analyzed using Multiplex bead arrays from samples drawn at the gestational week 24. The concentrations of T helper (Th)2-related interleukins (IL)-9 and IL-13 and Th1-related IL-12 correlated positively with prenatal depressive and overall anxiety symptom scores (p values, range 0.011-0.029). Higher interferon (IFN)-γ/IL-4 ratio (p = 0.039) and Th2-related IL-5 (p = 0.007) concentration correlated positively with depressive symptoms. Pregnancy-related anxiety score correlated positively with IL-12 (p = 0.041), IL-13 (p = 0.025), and anti-inflammatory IL-10 (p = 0.048) concentrations. IL-6 and TNF-α concentrations were unrelated to prenatal symptoms. As a novel finding, we observed positive correlations between concentrations of potentially proallergenic cytokines and maternal prenatal psychological symptoms. Different symptom measures may yield distinct cytokine responses. This provides hypotheses for studies on mechanisms bridging prenatal stress and child health.

Mental Health Comorbidities in Pediatric Chronic Pain: A Narrative Review of Epidemiology, Models, Neurobiological Mechanisms and Treatment

Chronic pain during childhood and adolescence can lead to persistent pain problems and mental health disorders into adulthood. Posttraumatic stress disorders and depressive and anxiety disorders are mental health conditions that co-occur at high rates in both adolescent and adult samples, and are linked to heightened impairment and disability. Comorbid chronic pain and psychopathology has been explained by the presence of shared neurobiology and mutually maintaining cognitive-affective and behavioral factors that lead to the development and/or maintenance of both conditions. Particularly within the pediatric chronic pain population, these factors are embedded within the broader context of the parent-child relationship. In this review, we will explore the epidemiology of, and current working models explaining, these comorbidities. Particular emphasis will be made on shared neurobiological mechanisms, given that the majority of previous research to date has centered on cognitive, affective, and behavioral mechanisms. Parental contributions to co-occurring chronic pain and psychopathology in childhood and adolescence will be discussed. Moreover, we will review current treatment recommendations and future directions for both research and practice. We argue that the integration of biological and behavioral approaches will be critical to sufficiently address why these comorbidities exist and how they can best be targeted in treatment.

The effects of vitamin B on the immune/cytokine network and their involvement in depression

Increasing evidence indicates that there are various interactions between the nervous system and the immune system, and that the immune system plays an important role in the pathogenesis of depression. Pro-inflammatory cytokines (such as IL-1, IL-6, TNF-α) have been implicated in the neurobiological manifestations of depression. The immune/cytokine network has a powerful influence on the brain. In addition, deficiency in B vitamins has been linked to depression. Hence, greater knowledge of how immune cells change in the presence of vitamin B derivatives could improve understanding of how immune changes may correlate with depression, all of which are discussed herein.

Dysthymia increases the risk of temporomandibular disorder: A population-based cohort study (A STROBE-Compliant Article)

Numerous studies have investigated the relationship between depression and temporomandibular disorders (TMD), but the conclusions remain vague. The aim of this study was to examine the causal effect between depression and TMD.The reporting of this study conforms to the STROBE statement. In this retrospective cohort study, all samples were recruited from a representative subdataset of 1 million insured persons for the year 2005 Longitudinal Health Insurance Database, who were randomly selected from all beneficiaries enrolled in the National Health Insurance program of Taiwan. We used a propensity score and stratified 926,560 patients into 2 groups (propensity1 = 588,429 and propensity2 = 338,131) and 4 cohorts (propensity1 with depression = 18,038, propensity1 without depression = 570,391, propensity2 with depression = 38,656, propensity2 without depression = 299,475) to detect the development of TMD among the depressive and nondepressive patients between 2004 and 2013.The positive correlative factors of TMD included female, total number of times seeking medical advice (TTSMA) for anxiety state, TTSMA for generalized anxiety disorder, TTSMA for mandible fracture, and TTSMA for unspecified anomaly of jaw size. The propensity2 group was represented by elder and female-predominant patients who used more psychiatric health resources. Among 3 types of depression, only dysthymia (so-called chronic depression) had a causal impact on TMD in the propensity 2 group. In the propensity 2 group, the hazard ratio of dysthymia for TMD measured by Cox's regression was 1.64 (95% confidence interval 1.28-2.09), after adjusting for demographic factors, psychiatric comorbidities, and maxillofacial confounders. The first-onset mean time of TMD as the consequence of dysthymia was 3.56 years (sd = 2.74, min = 0.08, median = 2.99, max = 9.73).This study demonstrates that dysthymia increases the risk of TMD in elderly and female-predominant patients who use more psychiatric health resources.