Understanding the somatic consequences of depression: biological mechanisms and the role of depression symptom profile

Diabetes and psychiatric illness in the total population of Stockholm

OBJECTIVE

Concomitant psychiatric disorders in people with diabetes affect morbidity and mortality. We aimed to study psychiatric morbidity in people with diabetes and the general population using administrative health care data in Stockholm County.

METHODS

The study population included all living persons who resided in Stockholm County, Sweden, on January 1, 2011 (N=2,058,408). Subjects with a diagnosis of diabetes were identified with data from all consultations in primary health care, specialist outpatient care and inpatient care during the time span 2009-2013. As outcome, information was obtained on all consultations due to any psychiatric diagnosis as well as, specifically, schizophrenia, bipolar disorders, depression, and anxiety disorders, in 2011-2013. Analyses were performed by age group and gender. Age-adjusted odds ratios (ORs) with 95% confidence intervals (95% CI) for women and men with diabetes, using individuals without diabetes as referents, were calculated.

RESULTS

Age-adjusted OR for all psychiatric diagnoses among people with diabetes was 1.296 (95% CI 1.267-1.326) for women and 1.399 (95% CI 1.368-1.432) for men. The greatest excess risk was found for schizophrenia, with OR 3.439 (95% CI 3.057-3.868) in women and 2.787 (95% CI 2.514-3.089) in men, with ORs between 1.276 (95% CI 1.227-1.327) and 1.714 (95% CI 1.540-1.905) for the remaining diagnoses.

CONCLUSION

The prevalence of psychiatric disorders is elevated in people with diabetes, which calls for preventive action to be taken to minimize suffering and costs to society.

Cellular aging in depression: Permanent imprint or reversible process?: An overview of the current evidence, mechanistic pathways, and targets for interventions

Depression might be associated with accelerated cellular aging. However, does this result in an irreversible state or is the body able to slow down or recover from such a process? Telomeres are DNA-protein complexes that protect the ends of chromosomes and generally shorten with age; and therefore index cellular aging. The majority of studies indicate that persons with depression have shorter leukocyte telomeres than similarly aged non-depressed persons, which may contribute to the observed unfavorable somatic health outcomes in the depressed population. Some small-scale preliminary studies raise the possibility that behavioral or pharmacological interventions may either slow down or else reverse this accelerated telomere shortening, possibly through increasing the activity of the telomere-lengthening enzyme telomerase. This paper covers the current state of evidence in the relationship between depression and the telomere-telomerase system and debates whether depression-related cellular aging should be considered a reversible process or permanent damage.

Elevated C-reactive protein, depression, somatic diseases, and all-cause mortality: a mendelian randomization study

BACKGROUND

Elevated levels of plasma C-reactive protein (CRP) have been associated with many diseases including depression, but it remains unclear whether this association is causal. We tested the hypothesis that CRP is causally associated with depression, and compared these results to those for cancer, ischemic heart disease, chronic obstructive pulmonary disease, and all-cause mortality.

METHODS

We performed prospective and instrumental variable analyses using plasma CRP levels and four CRP genotypes on 78,809 randomly selected 20- to 100-year-old men and women from the Danish general population. End points included hospitalization or death with depression and somatic diseases, prescription antidepressant medication use, and all-cause mortality.

RESULTS

A doubling in plasma CRP yielded an observed odds ratio (OR) of 1.28 (95% confidence interval [CI]: 1.23-1.33) for hospitalization or death with depression, whereas for genetically elevated CRP, the causal OR was .79 (95% CI: .51-1.22; observed vs. causal estimate, p = .03). For prescription antidepressant medication use, corresponding ORs were 1.12 (1.11-1.15) and .98 (.83-1.15; p = .08). These results were similar to those for risk of cancer (p = .002), ischemic heart disease (p = 4 × 10(-99)), chronic obstructive pulmonary disease (p = 6 × 10(-86)), and all-cause mortality (p = .001) examined in the same individuals.

CONCLUSIONS

Elevated CRP was associated with increased risk of depression in individuals in the general population, but genetically elevated CRP was not. This indicates that CRP per se is not a causal risk factor for depression.

The association between serum leptin and post stroke depression: results from a cohort study

BACKGROUND

Depression is a frequent mood disorder that affects around a third of stroke patients and has been associated with poorer outcomes. Our aim was to determine whether there was a relationship between inflammatory markers (leptin) and post-stroke depression (PSD).

METHODS

One hundred and ninety-one ischemic stroke patients admitted to the hospital within the first 24 hours after stroke onset were consecutively recruited and followed up for 3 months. Enzyme-linked immunosorbent assay (ELISA) was used to measure serum levels of leptin at admission. Based on the symptoms, diagnoses of depression were made in accordance with DSM-IV criteria for post-stroke depression at 3 month.

RESULTS

Forty-four patients (23.0%) were diagnosed as having major depression at 3 month. Patients with depression showed higher serum leptin levels at 3 month after stroke (32.2 [IQR, 20.8-57.7] v. 9.9 [IQR, 4.6-13.1]ng/ml, respectively; P = 0.000). Serum levels of leptin ≥20 ng/ml were independently associated with PSD [odds ratio (OR) 20.23, 95% confidence interval (CI) 9.11-51.26, P =  0.000], after adjusting for possible confounders.

CONCLUSIONS

Serum leptin levels elevated at admission were found to be associated with PSD and may provide a new proposal for the treatment of PSD.

Relationship between obesity and the risk of clinically significant depression: Mendelian randomisation study

BACKGROUND

Obesity has been shown to be associated with depression and it has been suggested that higher body mass index (BMI) increases the risk of depression and other common mental disorders. However, the causal relationship remains unclear and Mendelian randomisation, a form of instrumental variable analysis, has recently been employed to attempt to resolve this issue.

AIMS

To investigate whether higher BMI increases the risk of major depression.

METHOD

Two instrumental variable analyses were conducted to test the causal relationship between obesity and major depression in RADIANT, a large case-control study of major depression. We used a single nucleotide polymorphism (SNP) in FTO and a genetic risk score (GRS) based on 32 SNPs with well-established associations with BMI.

RESULTS

Linear regression analysis, as expected, showed that individuals carrying more risk alleles of FTO or having higher score of GRS had a higher BMI. Probit regression suggested that higher BMI is associated with increased risk of major depression. However, our two instrumental variable analyses did not support a causal relationship between higher BMI and major depression (FTO genotype: coefficient -0.03, 95% CI -0.18 to 0.13, P = 0.73; GRS: coefficient -0.02, 95% CI -0.11 to 0.07, P = 0.62).

CONCLUSIONS

Our instrumental variable analyses did not support a causal relationship between higher BMI and major depression. The positive associations of higher BMI with major depression in probit regression analyses might be explained by reverse causality and/or residual confounding.

Serum BDNF concentrations as peripheral manifestations of depression: evidence from a systematic review and meta-analyses on 179 associations (N=9484)

Meta-analyses, published in 2008-2010, have confirmed abnormally low serum brain-derived neurotrophic factor (BDNF) concentrations in depressed patients and normalization of this by antidepressant treatment. These findings are believed to reflect peripheral manifestations of the neurotrophin hypothesis, which states that depression is secondary to an altered expression of BDNF in the brain. Since the publication of these meta-analyses, the field has seen a huge increase in studies on these topics. This motivated us to update the evidence on the aforementioned associations and, in addition, to compile the data on serum BDNF concentrations in relation to the symptom severity of depression. Using a manifold of data as compared with earlier meta-analyses, we find low serum BDNF concentrations in 2384 antidepressant-free depressed patients relative to 2982 healthy controls and to 1249 antidepressant-treated depressed patients (Cohen's d=-0.71 and -0.56, P-values <0.0000001). When publication bias is accounted for, these effect-sizes become substantially smaller (d=-0.47 and -0.34, respectively, P-values<0.0001). We detect between-study heterogeneity in outcomes for which only year of publication and sample size are significant moderators, with more recent papers and larger samples sizes in general being associated with smaller between-group differences. Finally, the aggregated data negate consistent associations between serum BDNF concentrations and the symptom severity of depression. Our findings corroborate the claim that altered serum BDNF concentrations are peripheral manifestations of depression. However, here we highlight that the evidence for this claim is slimmer as was initially thought and amidst a lot of noise.

Pain, not chronic disease, is associated with the recurrence of depressive and anxiety disorders

BACKGROUND

Studies suggest that poor physical health might be associated with increased depression and anxiety recurrence. The objectives of this study were to determine whether specific chronic diseases and pain characteristics are associated with depression and anxiety recurrence and to examine whether such associations are mediated by subthreshold depressive or anxiety symptoms.

METHODS

1122 individuals with remitted depressive or anxiety disorder (Netherlands Study of Depression and Anxiety) were followed up for a period of four years. The impact of specific chronic diseases and pain characteristics on recurrence was assessed using Cox regression and mediation analyses.

RESULTS

Chronic diseases were not associated with recurrence. Neck (HR 1.45, p < .01), chest (HR 1.65, p < .01), abdominal (HR 1.52, p < .01) pain, an increase in the number of pain locations (HR 1.10, p < .01) and pain severity (HR 1.18, p = .01) were associated with an increased risk of depression recurrence but not anxiety. Subthreshold depressive symptoms mediated the associations between pain and depression recurrence.

CONCLUSIONS

Pain, not chronic disease, increases the likelihood of depression recurrence, largely through its association with aggravated subthreshold depressive symptoms. These findings support the idea of the existence of a mutually reinforcing mechanism between pain and depression and are indicative of the importance of shedding light on neurobiological links in order to optimize pain and depression management.

Metabolic syndrome improvement in depression six months after prescribing simple hygienic-dietary recommendations

Background

Changes in diet and exercise have been separately demonstrated to improve Depression, although scientific evidence available is scarce. In a previously published controlled study, just recommending these and other lifestyle measures (sleep restriction and sunlight exposure) in combination once, patients experienced improvements in their depressive symptoms six months later. In this sample, one in three depressive patients had metabolic syndrome (MetS) at baseline. First line treatment of MetS condition is hygienic-dietetic, being Mediterranean diet and exercise especially important. Therefore we analyzed if lifestyle recommendations also improved their metabolic profile.

Findings

During the sixth month evaluation, a smaller number of patients from the group receiving hygienic-dietary recommendations met MetS criteria comparing with the control group.

Conclusions

This study suggests that costless lifestyle recommendations, such as exercise and Mediterranean diet, have the capacity to promote both mental and physical health in a significant proportion of depressive patients. Further research is needed to confirm or discard these preliminary findings.

Dietary patterns and the risk of depression in adults: a systematic review of observational studies

PURPOSE

Diet, a modifiable lifestyle factor, may influence the development of depression. We performed a systematic review of observational studies examining the relationship between dietary patterns and depression in healthy adults.

METHODS

A literature research was conducted searching various electronic databases up to May 2013. Study selection was based on predefined inclusion and exclusion criteria. Included studies were reviewed, and relevant data were extracted by two independent researchers. Due to a high level of heterogeneity, no meta-analysis was conducted. Therefore, main results are presented in a descriptive way.

RESULTS

In total, 16 studies met the inclusion criteria and are part of this review. Dietary patterns most commonly found were traditional/healthy patterns, Western/unhealthy patterns and Mediterranean patterns. The available literature suggests a protective effect of healthy and Mediterranean patterns, as well as a potential positive association of Western patterns and depression. However, comparison of the included studies was difficult, due to differences in relevant study characteristics and methodological limitations.

CONCLUSIONS

There are indications that dietary patterns may have influence on the onset of depression, but no firm conclusion can be drawn at this point. Further research is needed to clarify the diet-depression relationship, preferably in the form of methodological strong prospective studies using more homogeneous methods.

Is excess mortality higher in depressed men than in depressed women? A meta-analytic comparison

BACKGROUND

It is not well-established whether excess mortality associated with depression is higher in men than in women.

METHODS

We conducted a meta-analysis of prospective studies in which depression was measured at baseline, where mortality rates were reported at follow-up, and in which separate mortality rates for men and women were reported. We conducted systematic searches in bibliographical databases and calculated relative risks of excess mortality in men and women.

RESULTS

Thirteen studies were included. Among the people with depression, excess mortality in men was higher than in women (RR=1.97; 1.63-2.37). Compared with non-depressed participants, excess mortality was increased in depressed women (RR=1.55; 95% CI: 1.32-1.82), but not as much as in men (RR=2.04; 95% CI: 1.76-2.37), and the difference between excess mortality in men was significantly higher than in women (p<0.05).

CONCLUSIONS

Excess mortality related to depression is higher in men than in women. Although the exact mechanisms for this difference are not clear, it may point at differential or more intensified pathways leading from depression to increased mortality in depressed men compared to women.

Predictive value of baseline resistance in early response to antidepressants

BACKGROUND

Major Depressive Disorder (MDD) is the 3rd source for burden worldwide according to the World Health Organization (WHO). This comes partly from unsatisfactory response rates after usual treatment, highlighting the need for early indicators such as early improvement of depressive symptoms to adapt treatment strategies, especially for severe inpatients. Thus our objective was to assess the predictive value of baseline partial resistance in early antidepressant response (EAR), hypothesizing that previous treatment failures would decrease the probability of early response.

METHODS

We included 122 consecutive inpatients with current unipolar MDE. The Mini-Neuropsychiatric Interview was used to ascertain DSM-IV diagnoses of MDD as well as psychiatric comorbidities, and to exclude patients with a history of bipolar disorder. A specifically designed questionnaire was used to collect data on previous treatment trials for the current episode so as to generate scores on the five existing methods for quantifying treatment resistance. We prospectively assessed EAR, defined as a 50% decrease in MADRS after 14 days of steady regimen of antidepressant.

RESULTS

In the per protocol sample (N=76), multivariate analyses showed that psychotic features at baseline remained an independent predictor of absence of EAR (p<.01), unlike baseline partial resistance, which may rather be associated with a lack of any improvement.

LIMITATIONS

Lack of data about further response and non-randomized treatment allocation.

CONCLUSION

Available methods for quantifying treatment resistance are heterogeneous and do not predict short-term response among severely depressed inpatients, despite potential usefulness in predicting a lack of early improvement.

Prevalence of anxiety and depression among diabetic African patients in Guinea: association with HbA1c levels

AIM

The prevalence and risk factors associated with symptoms of anxiety and depression were determined in African people with diabetes.

METHODS

This cross-sectional study involved 491 outpatients with type 2 diabetes (T2D) recruited from four diabetes clinics (Conakry, Labé, Boké and Kankan) in Guinea. The Hospital Anxiety and Depression Scale (HADS) was used to evaluate symptoms of anxiety and depression. Logistic regression analysis stratified by gender was performed to identify the associated risk factors.

RESULTS

Anxiety and depression symptoms were present in 58.7% and 34.4%, respectively, of the 491 patients with T2D (62.7% women, mean±SD age: 57.9±10.2years). Odds ratios (95% CI) of risk factors independently associated with anxiety were urban residence [2.98 (1.81-4.89)] in women, and low socioeconomic status [0.19 (0.05-0.70)] and HbA1c≥9.0% [2.61 (1.0-6.39)] in men. Factors associated with depression were urban residence [2.13 (1.27-3.58)], older age [1.03 (1.01-1.06)], low socioeconomic status [2.21 (1.34-3.66)] and no previous measurement of HbA1c [12.45 (1.54-100.34)] in women, and insulin therapy [2.28 (1.05-4.92)] and HbA1c≥9.0% [3.85 (1.02-14.48)] in men.

CONCLUSION

Anxiety and depression symptoms in people with type T2D are common in Guinea. Urban residence, low socioeconomic status and high levels of HbA1c were significantly associated with a greater risk of anxiety and depression, highlighting the psychological burden related to diabetes in Africa.

The ceramide system as a novel antidepressant target

Major depression is a systems disorder which impairs not only central nervous system aspects of mood and behavior but also peripheral organ systems. Current views on the pathogenesis and treatment of depression are predominantly based on proteins and transmitters and thus are difficult to reconcile central with peripheral pathomechanisms. Recent research showed that there is also a lipid-based pathway involved in the pathology of depression, which is activated by psychosocial stress, oxidative stress, or inflammation. Inducible dysfunction of the ceramide pathway, which is abundant in the brain as well as in peripheral organs, may account for mood disorder, behavioral symptoms, and further promote inflammation and oxidative stress in peripheral systems. As such, the lipid ceramide pathway may provide the missing link between brain dysfunction and somatic symptoms of depression. Pharmacological interventions that reduce ceramide abundance also show antidepressant action and may promise a better treatment of major depression.

Pressure pain sensitivity as a marker for stress and pressure pain sensitivity-guided stress management in women with primary breast cancer

OBJECTIVES

To validate (1) Pressure Pain Sensitivity (PPS) as a marker for stress and (2) a PPS-guided intervention in women with primary Breast Cancer (BC).

METHODS

(1) A total of 58 women with BC were examined before and after 6 months of intervention. A control group of 165 women office employees was divided in a High Stress Group (HSG, n = 37) and a Low Stress Group (LSG, n = 128) to evaluate the association between PPS, questionnaire-related Quality of Life (QOL) and self-evaluated stress. (2) A PPS-guided stress management program (n = 40) was compared to a Psychosocial Group Intervention (PGI, n = 91) and no treatment (n = 86) with respect to a European Organization for Research and Treatment of Cancer (EORTC) questionnaire measured QOL.

RESULTS

(1) Resting PPS and changes in PPS during the intervention period correlated significantly to EORTC and Short Form 36 (SF 36) main scores: (all p < 0.05). Between BC, HSG and LSG there was a significant and positive correlation with respect to PPS, SF 36 main scores, depression, and clinical stress scores (all p < 0.05). However, the BC group scored significantly lower than both HSG and LSG (both p < 0.05) with respect to self-evaluated stress. (2) The PPS-guided intervention group improved EORTC main score, pain and nausea, when compared to the control groups (all p < 0.05).

CONCLUSIONS

PPS was positively associated with QOL, which was in contrast to self-evaluated stress. PPS-guided intervention improved QOL in women with breast cancer.

The association between leptin and depressive symptoms is modulated by abdominal adiposity

BACKGROUND

Evidence for a role of leptin in depression is limited and conflicting. Inconclusive findings may be explained by the complex effect of obesity on leptin signaling. In particular, both hyperleptinemia due to leptin resistance in obese persons as well as low leptin in lean persons can imply that low leptin biological signaling is associated with an increased risk of significant depressive symptoms. We tested whether the relationship between leptin and depressive symptoms is modulated by abdominal adiposity in two population-based studies.

METHODS

Data were from 851 participants (65-94 years) of the InCHIANTI Study and 1064 (26-93 years) of the Baltimore Longitudinal Study of Aging (BLSA). Plasma concentrations of leptin, waist circumference and depressive symptoms via the Center for Epidemiological Studies-Depression scale (CES-D) were assessed. In longitudinal InCHIANTI analyses onset of depressed mood (CES-D≥20) was evaluated over a 9-year follow-up.

RESULTS

In pooled cross-sectional analyses the interaction between leptin and waist circumference was significantly associated with CES-D scores ((log)leptin-by-waist interaction p=0.01). Also in longitudinal analyses, the (log)leptin-by-waist interaction term significantly (p=0.04) predicted depressed mood onset over time; depressed mood risk was especially increased for high levels of both leptin and waist circumference.

CONCLUSIONS

The present findings suggest that low leptin signaling rather than low leptin concentration is a risk factor for depression. Future studies should develop proxy measures of leptin signaling by combining information on abdominal adiposity and leptin level to be used for clinical and research applications.

Depressive symptoms are not associated with forearm bone accrual during adolescence

Although depression has been associated to worst bone physical properties in adulthood, this study showed that depressive symptoms were not significantly associated to bone mineral density measured at the forearm during adolescence.

PURPOSE

Depressive conditions have been related to the reduction of bone mineral density (BMD) in adulthood. Though it is possible to hypothesize that depressive symptoms present similar effects in bone mineral accrual during adolescence, such association is poorly researched. Therefore, we aimed to study the relation between depressive symptoms and forearm BMD during adolescence.

METHODS

The study is based on the Epidemiological Health Investigation of Teenagers cohort that sampled adolescents born in 1990 and enrolled in public and private schools of Porto during the 2003/2004 academic year. At baseline (n = 2,160) and at 17 years of age (n = 1,716), depressive symptoms were evaluated using the Beck Depression Inventory-II (BDI-II). BMD (grams per square centimetre) was measured at the non-dominant forearm using dual-energy X-ray absorptiometry. Sex-specific crude and adjusted linear regression coefficients (β) and the corresponding 95 % confidence intervals (95 % CIs) were calculated to estimate the cross-sectional and prospective associations between depressive symptoms and forearm BMD.

RESULTS

In both sexes, in early and late adolescence, depressive symptoms presented no statistically significant association with forearm BMD (β Girls13 = 0.09, 95 % CI = -0.43 to 0.61; β Girls17 = 0.10, 95 % CI = -0.43 to 0.64; β Boys13 = -0.10, 95 % CI = -0.96 to 0.76; β Boys17 = 0.49, 95 % CI = -0.96 to 1.93). Similarly, there were no significant associations between depressive symptoms and the annual forearm BMD change during adolescence in girls and boys (β Girls_BDI-II_13-17_remained_lowest = -0.85, 95 % CI = -4.62 to 2.92 vs. β Girls_BDI-II_13-17_remained_highest = -1.87, 95 % CI = -5.06 to 1.31; β Boys_BDI-II_13-17_remained_lowest = 0.48, 95 % CI = -5.30 to 6.26 vs. β Boys_BDI-II_13-17_remained_highest = 1.36, 95 % CI = -3.25 to 5.97).

CONCLUSIONS

Depressive symptoms, with the range of severity observed in the general adolescent population, were not associated with changes in forearm bone mineral density during adolescence. Further research based on measurements of different skeletal sites is needed in order to detect a systemic effect of depression on growing bone.

Gender differences in major depressive disorder: results from the Netherlands study of depression and anxiety

BACKGROUND

Although an overall gender difference in prevalence of major depressive disorder (MDD) has been well established, several questions concerning gender differences in the clinical manifestation of depression remain. This study aims to identify gender differences in psychopathology, treatment, and public health consequences in patients with MDD.

METHODS

Baseline data from the Netherlands Study of Depression and Anxiety (NESDA) were used, including 1115 participants (364 men, 751 women, mean age 41 years) with a DSM-IV diagnosis of current MDD. Characteristics studied included symptom profiles, comorbidity, treatment, and public health consequences.

RESULTS

Women reported a younger age of onset of single (27.8 years vs. 31.6 years; p=0.001) and recurrent MDD (24.8 years vs. 27.6 years; p=0.014), a higher comorbidity of panic disorder with agoraphobia (24.9% vs. 17.3%; p=0.006) and life-time overall anxiety disorder (77.6% vs. 71.4%; p=0.029) than men. More men than women suffered from comorbid alcohol dependence or abuse (48.1% vs. 24.5%; p<0.001). An increased prevalence of atypical depression in women (24.6% vs. 17.3%; p=0.009) was found. Women were treated more frequently by an alternative caretaker (20.6% vs. 14.8%; p=0.025), men more often in mental health care organizations (61.0% vs. 53.7%; p=0.025). No gender differences in frequency of medication use or counseling were found.

LIMITATIONS

Cross sectional design.

CONCLUSIONS

Main gender differences in the clinical presentation of MDD concerned a younger age of onset, higher anxiety and lower alcohol use comorbidity and higher prevalence of atypical depression in women. These differences were accompanied by differences in health care use.

Depression and depression treatment in women with spinal cord injury

BACKGROUND

Research has documented high rates of depression in people with spinal cord injury (SCI); however, most SCI research is conducted with predominantly male study participants. Additional research is needed on depression and depression treatment among women with SCI.

OBJECTIVE

Study objectives were to examine depression, correlates of depression, and depression treatment in a sample of women with SCI.

METHODS

The sample included 51 ethnically and racially diverse women with SCI who participated in a larger study on secondary conditions of women with diverse physical disabilities. Recruited through health clinics and community organizations in a large metropolitan area, participants completed structured interviews that included demographic and disability characteristics and measures of health and health care utilization.

RESULTS

Scores on the Beck Depression Inventory-II (BDI-II) indicated that 41% of the women had depressive symptomatology in the mild to severe range. BDI-II scores were significantly related to more severe secondary conditions, greater pain, and poorer health perceptions but not to demographic or disability variables. Nearly a third (n = 16) of the women had scores exceeding the standard cutoff for significant clinical depressive symptomatology, yet only 5 of those had received any treatment for depression in the past 3 months and only 1 had received counseling or psychotherapy. Lifelong depression treatment showed a similar pattern of predominantly pharmacologic treatment.

CONCLUSION

Depression is a common problem for women with SCI, and many do not receive treatment, particularly psychological treatment. Disability-sensitive and affordable depression treatment must be made available to women with SCI.

Dysregulated physiological stress systems and accelerated cellular aging

Exposure to chronic stressors is associated with accelerated biological aging as indicated by reduced leukocyte telomere length (LTL). This impact could be because of chronic overactivation of the body's physiological stress systems. This study examined the associations between LTL and the immune system, hypothalamic-pituitary-adrenal axis and autonomic nervous system. LTL was assessed in 2936 adults from the Netherlands Study of Depression and Anxiety. Inflammation markers (interleukin-6, c-reactive protein, tumor necrosis factor-alpha), hypothalamic-pituitary-adrenal-axis indicators (salivary cortisol awakening curve [area under the curve indicators, with respect to the ground and increase], evening levels, 0.5 mg dexamethasone cortisol suppression ratio), and autonomic nervous system measures (heart rate, respiratory sinus arrhythmia, pre-ejection period) were determined. Linear regression analyses were performed and adjusted for sociodemographic, lifestyle and clinical factors. Shorter LTL was significantly associated with higher c-reactive protein, interleukin-6, area under the curve with respect to increase, and heart rate. A cumulative index score was calculated based on the number of highest tertiles of these 4 stress markers. LTL demonstrated a significant gradient within subjects ranging from having zero (5528 base pairs) to having 4 elevated stress markers (5371 base pairs, p for trend = 0.002), corresponding to a difference of 10 years of accelerated biological aging. Contrary to the expectations, shorter LTL was also associated with longer pre-ejection period, indicating lower sympathetic tone. This large-scale study showed that inflammation, high awakening cortisol response, and increased heart rate are associated with shorter LTL, especially when they are dysregulated cumulatively.

The association between immune activation and manic symptoms in patients with a depressive disorder

Although recent studies have shown that immunological processes play an important role in the pathophysiology of mood disorders, immune activation may only be present in specific subgroups of patients. Our study aimed to examine whether immune activation was associated with (a) the presence of manic symptoms and (b) the onset of manic symptoms during 2 years of follow-up in depressed patients. Patients with a depressive disorder at baseline (N=957) and healthy controls (N=430) were selected from the Netherlands Study of Depression and Anxiety. Assessments included lifetime manic symptoms at baseline and two-year follow up, as well as C-reactive protein (CRP), interleukin-6 (IL-6) and tumor necrosis factor alpha (TNF-α) at baseline. Within depressed patients, immune activation was not related to the presence or absence of lifetime manic symptoms at baseline. However, CRP levels were strongly elevated in depressed men who developed manic symptoms compared with those who did not develop manic symptoms over 2 years (P<0.001, Cohen's d=0.89). IL-6 and TNF-α were also higher in depressed men with an onset of manic symptoms, but this association was not significant. However, we found that the onset of manic symptoms was particularly high in men with multiple elevated levels of inflammatory markers. Depressed men who developed manic symptoms during follow-up had increased immunological activity (especially CRP) compared with depressed men who did not develop manic symptoms. Further research should explore whether a treatment approach focusing on inflammatory processes may be more effective in this specific subgroup of depressed patients.