Depressive symptoms and cognitive decline in older adults

OBJECTIVES

Few studies have examined the impact of late-life depression trajectories on specific domains of cognitive function. This study aims to delineate how different depressive symptom trajectories specifically affect cognitive function in older adults.

DESIGN

Prospective longitudinal cohort study.

SETTING

Australia and the United States of America.

PARTICIPANTS

In total, 11,035 community-dwelling older adults with a mean age of 75 years.

MEASUREMENTS

Depressive trajectories were modelled from depressive symptoms according to annual Centre for Epidemiological Studies Depression Scale 10 (CES-D-10) surveys. Four trajectories of depressive symptoms were identified: low ("nondepressed"), consistently mild ("subthreshold depression"), consistently moderate ("persistent depression"), and initially low but increasing ("emerging depression"). Global cognition (Modified Mini-Mental State Examination [3MS]), verbal fluency (Controlled Oral Word Association Test [COWAT]), processing speed (Symbol Digit Modalities Test [SDMT]), episodic memory (Hopkins Verbal Learning Test - Revised [HVLT-R]), and a composite z-score were assessed over a subsequent median 2 years.

RESULTS

Subthreshold depression predicted impaired performance on the SDMT (Cohen's d -0.04) and composite score (-0.03); emerging depression predicted impaired performance on the SDMT (-0.13), HVLT-R (-0.09), 3 MS (-0.08) and composite score (-0.09); and persistent depression predicted impaired performance on the SDMT (-0.08), 3 MS (-0.11), and composite score (-0.09).

CONCLUSIONS

Depressive symptoms are associated with later impaired processing speed. These effects are small. Diverse depression trajectories have different impacts on cognitive function.

Lithium use and bone health in women with bipolar disorder: A cross-sectional study

INTRODUCTION

Several psychiatric disorders and medications used to treat them appear to be independently associated with skeletal deficits. As there is increasing evidence that lithium possesses skeletal protective properties, we aimed to investigate the association between lithium use and bone health in a group of women with bipolar disorder.

METHOD

Women with bipolar disorder (n = 117, 20+ years) were recruited from south-eastern Australia. Bipolar disorder was confirmed using a clinical interview (SCID-I/NP). Bone mineral density (BMD; g/cm2 ) was measured at the spine, hip and total body using dual-energy x-ray absorptiometry and low bone mass determined by BMD T-score of <-1.0. Weight and height were measured, socioeconomic status (SES) determined and information on medication use and lifestyle factors self-reported. Linear and logistic regression were used to test associations between lithium and (i) BMD and (ii) low bone mass, respectively.

RESULTS

Thirty-five (29.9%) women reported current lithium use. Lithium users and non-users differed in regard to SES and BMD; otherwise, groups were similar. After adjustments, mean BMD among lithium users was 5.1% greater at the spine (1.275 [95% CI 1.229-1.321] vs. 1.214 [1.183-1.244] g/cm2 , p = 0.03), 4.2% greater at the total hip (0.979 [0.942-1.016] vs. 0.938 [0.910-0.966] g/cm2 , p = 0.03) and 2.2% greater at the total body (1.176 [1.148-1.205] vs. 1.150 [1.129-1.171] g/cm2 , p = 0.08) compared to participants not receiving lithium. Lithium users were also less likely to have low bone mass (22.9% vs. 43.9%, p = 0.031). Associations persisted after adjustment for confounders.

CONCLUSION

These data suggest lithium is associated with greater BMD and reduced risk of low bone mass in women with bipolar disorder. Research into the underlying mechanisms is warranted.

Diagnosis and Treatment of Bipolar Disorder: A Review

Importance

Bipolar disorder affects approximately 8 million adults in the US and approximately 40 million individuals worldwide.

Observations

Bipolar disorder is characterized by recurrent episodes of depression and mania or hypomania. Bipolar depressive episodes are similar to major depressive episodes. Manic and hypomanic episodes are characterized by a distinct change in mood and behavior during discrete time periods. The age of onset is usually between 15 and 25 years, and depression is the most frequent initial presentation. Approximately 75% of symptomatic time consists of depressive episodes or symptoms. Early diagnosis and treatment are associated with a more favorable prognosis. Diagnosis and optimal treatment are often delayed by a mean of approximately 9 years following an initial depressive episode. Long-term treatment consists of mood stabilizers, such as lithium, valproate, and lamotrigine. Antipsychotic agents, such as quetiapine, aripiprazole, asenapine, lurasidone, and cariprazine, are recommended, but some are associated with weight gain. Antidepressants are not recommended as monotherapy. More than 50% of patients with bipolar disorder are not adherent to treatment. Life expectancy is reduced by approximately 12 to 14 years in people with bipolar disorder, with a 1.6-fold to 2-fold increase in cardiovascular mortality occurring a mean of 17 years earlier compared with the general population. Prevalence rates of metabolic syndrome (37%), obesity (21%), cigarette smoking (45%), and type 2 diabetes (14%) are higher among people with bipolar disorder, contributing to the risk of early mortality. The annual suicide rate is approximately 0.9% among individuals with bipolar disorder, compared with 0.014% in the general population. Approximately 15% to 20% of people with bipolar disorder die by suicide.

Conclusions and Relevance

Bipolar disorder affects approximately 8 million adults in the US. First-line therapy includes mood stabilizers, such as lithium, anticonvulsants, such as valproate and lamotrigine, and atypical antipsychotic drugs, such as quetiapine, aripiprazole, asenapine, lurasidone, and cariprazine.

The effect of depressive symptoms on disability-free survival in healthy older adults: A prospective cohort study

BACKGROUND

Gerontology and ageing research are increasingly focussing on healthy life span (healthspan), the period of life lived free of serious disease and disability. Late-life depression (LLD) is believed to impact adversely on physical health. However, no studies have examined its effect on healthspan. This study investigated the effect of LLD and subthreshold depression on disability-free survival, a widely accepted measure of healthspan.

METHODS

This prospective cohort study used data from the ASPirin in Reducing Events in the Elderly study. Participants were aged ≥70 years (or ≥65 years for African-American and Hispanic participants) and free of dementia, physical disability and cardiovascular disease. Depressive symptoms were measured using the 10-item Centre for Epidemiological Studies Depression Scale (CES-D-10). LLD and subthreshold depression were defined as CES-D-10 scores ≥8 and 3-7, respectively. Disability-free survival was defined as survival free of dementia and persistent physical disability.

RESULTS

A total of 19,110 participants were followed up for a maximum of 7.3 years. In female participants, LLD was associated with lower disability-free survival adjusting for sociodemographic and lifestyle factors, medical comorbidities, polypharmacy, physical function and antidepressant use (HR, 1.50; 95% CI, 1.23-1.82). In male participants, LLD was associated with lower disability-free survival adjusting for sociodemographic and lifestyle factors (HR, 1.30; 95% CI, 1.03-1.64). Subthreshold depression was also associated with lower disability-free survival in both sexes.

CONCLUSIONS

LLD may be a common and important risk factor for shortened healthspan.

Trajectories of depressive symptoms in older adults and associated health outcomes

With the progressive aging of the world's population, prolongation of a healthy lifespan in old age has become a medical research priority. The presence of depressive symptoms in later life is associated with poor health prognosis and increased mortality^1,2. Here we explore distinct trajectories of depressive symptoms in later life and their association with several health-related outcomes in 19,110 older individuals followed for a median of 4.7 years. Using a latent class, mixed-modeling approach we identified four distinct trajectories of depressive symptoms with scoring patterns of consistently low, moderate, emerging and persistently high. Compared to those with minimal depressive symptoms, membership of any other class was associated with specific patterns of baseline sociodemographic and medical factors. Membership of any group with depressive symptoms was associated with a higher likelihood of health events, including physical disability, cancer and major bleeding episodes. Membership of the persistently depressed class was associated with increased mortality, while a diagnosis of dementia was generally limited to the class with initially low and progressively rising symptoms. The course of depressive symptoms in older individuals can vary widely and depend on several factors. The presence of depressive symptoms, including those that do not meet criteria for major depression, can flag a poor prognosis and risk for specific health conditions. Systematic assessment of depressive symptoms may facilitate early identification of at-risk populations.

Minocycline as adjunctive treatment for major depressive disorder: Pooled data from two randomized controlled trials

BACKGROUND

Randomized controlled clinical trials that have investigated minocycline as an adjunctive treatment for major depressive disorder have proved promising. Data from two studies were pooled to evaluate more definitively whether the addition of minocycline to standard treatment for major depressive disorder leads to an improvement of depressive symptoms when compared with placebo.

METHODS

Both studies were multi-site, double-blinded, placebo-controlled trials of minocycline 200 mg/day added to treatment as usual during a 12-week period. The primary outcome measure was change in depressive symptoms (Montgomery-Asberg Depression Rating Scale in Dean et al. and Hamilton Depression Rating Scale in Husain et al.). Secondary outcomes were change in depression severity (Montgomery-Asberg Depression Rating Scale for Dean et al. and 9-item Patient Health Questionnaire in Husain et al.), anxiety severity (Hamilton Anxiety Rating Scale in Dean et al. and Generalized Anxiety Disorder 7-item scale in Husain et al.) and functional status, which were also evaluated as potential mediators on the primary outcome.

RESULTS

A total of 112 participants were included in the pooled data (Dean et al., n = 71; Husain et al., n = 41). A significant change from baseline to week 12 was noted in depressive symptoms - differential change (Placebo vs Minocycline): 9.0, 95% confidence interval = [4.2, 13.9], Cohen's D (95% confidence interval): 0.71 [0.29, 1.14], p < 0.001 - anxiety severity - differential change (Placebo vs Minocycline): 0.38, confidence interval = [0.00, 0.75], Cohen's D (95% confidence interval): 0.41 [0.00, 0.82], p = 0.050) and functional status - differential change (Placebo vs Minocycline): 1.0, 95% confidence interval = [0.4, 1.5], Cohen's D (95% confidence interval): 0.76 [0.34, 1.19], p = 0.001). Duration of illness, current use of benzodiazepine and pain medication were identified as moderators, whereas functional status as a mediator/predictor.

CONCLUSION

The improvement of depressive symptoms, anxiety severity and functional status is promising and suggests that minocycline has potential as an adjunctive treatment for major depressive disorder. However, further studies are warranted to confirm therapeutic effects of minocycline in major depressive disorder.

TRIAL REGISTRATIONS

NCT02263872, registered October 2014, and ACTRN12612000283875, registered March 2012.

Major Depressive Disorder in Older Patients as an Inflammatory Disorder: Implications for the Pharmacological Management of Geriatric Depression

Depression is a common and highly disabling condition in older adults. It is a heterogenous disorder and there is emerging evidence of a link between inflammation and depression in older patients, with a possible inflammatory subtype of depression. Persistent low-level inflammation, from several sources including psychological distress and chronic disease, can disrupt monoaminergic and glutaminergic systems to create dysfunctional brain networks. Despite the evidence for the role of inflammation in depression, there is insufficient evidence to recommend use of any putative anti-inflammatory agent in the treatment of depression in older adults at this stage. Further characterisation of markers of inflammation and stratification of participants with elevated rates of inflammatory markers in treatment trials is needed.

Effect of Aspirin vs Placebo on the Prevention of Depression in Older People: A Randomized Clinical Trial

IMPORTANCE

Depression is associated with increased inflammation, which may precede its onset, especially in older people. Some preclinical data suggest potential antidepressant effects of aspirin, supported by limited observational data suggesting lower rates of depression in individuals treated with aspirin. There currently appears to be no evidence-based pharmacotherapies for the primary prevention of depression.

OBJECTIVE

To determine whether low-dose aspirin (100 mg) reduces the risk of depression in healthy older adults.

DESIGN, SETTING, AND PARTICIPANTS

This double-blinded, placebo-controlled randomized clinical trial was a substudy of the Aspirin in Reducing Events in the Elderly (ASPREE) trial, which examined if aspirin increased healthy life span, defined as survival free of dementia and disability. The prespecified secondary outcome was depression. Individuals of all races/ethnicities older than 70 years in Australia, as well as white individuals older than 70 years and black and Hispanic individuals older than 65 years in the United States, were included.

INTERVENTIONS

Participants were randomized to aspirin (100 mg daily) or placebo, with a median (interquartile range) follow-up of 4.7 (3.5-5.6) years.

MAIN OUTCOMES AND MEASURES

The primary outcome was a proxy measure of major depressive disorder defined as a score of 8 or more on the Center for Epidemiologic Studies Depression 10-item (CES-D-10) scale.

RESULTS

Of the 19 114 participants enrolled in the trial, 9525 received aspirin and 9589 received a placebo. The mean (SD) age was 75.2 (4.0) years in the aspirin group and 75.1 (4.5) years in the placebo group; 9531 (56.4%) were women. Participants' demographics and clinical characteristics at baseline were similar between groups. A total of 79 886 annual CES-D-10 measurements were taken, with a mean of 4.2 measurements per participant. There were no significant differences at annual visits in the proportions of CES-D-10 scores of 8 or more between the aspirin and placebo groups. The incidence rate of new CES-D-10 scores of 8 or more was 70.4 events per 1000 person-years in the aspirin group and 69.1 in the placebo group (hazard ratio, 1.02 [95% CI, 0.96-1.08]; P = .54).

CONCLUSIONS AND RELEVANCE

Low-dose aspirin did not prevent depression in this large-scale study of otherwise healthy older adults.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT01038583.

Patterns of Association between Depressive Symptoms and Chronic Medical Morbidities in Older Adults

OBJECTIVES

To investigate the association between depressive symptoms and several medical morbidities, and their combination, in a large older population.

DESIGN

Cross-sectional study of baseline data from the ASPirin in Reducing Events in the Elderly (ASPREE) trial.

SETTING

Multicentric study conducted in Australia and the United States.

PARTICIPANTS

A total of 19,110 older adults (mean age = 75 years [standard deviation = ±4.5]).

MEASUREMENTS

Depressive symptoms were measured using the Center for Epidemiological Studies Depression (CES-D 10) scale. Medical morbidities were defined according to condition-specific methods. Logistic regression was used to calculate odds ratios (ORs) with 95% confidence intervals (CIs) to test associations before and after accounting for possible confounders.

RESULTS

Depressive symptoms were significantly associated with obesity (OR = 1.19; 95% CI = 1.07-1.32), diabetes (OR = 1.22; 95% CI = 1.05-1.42), gastroesophageal reflux disease (GERD) (OR = 1.41; 95% CI = 1.28-1.57), metabolic syndrome (OR = 1.16; 95% CI = 1.03-1.29), osteoarthritis (OR = 1.41; 95% CI = 1.27-1.57), respiratory conditions (OR = 1.25; 95% CI = 1.10-1.42), history of cancer (OR = 1.19; 95% CI = 1.05-1.34), Parkinson's disease (OR = 2.56; 95% CI = 1.83-3.56), polypharmacy (OR = 1.60; 95% CI = 1.44-1.79), and multimorbidity (OR = 1.29; 95% CI = 1.12-1.49). No significant association was observed between depressive symptoms and hypertension, chronic kidney disease, dyslipidemia, and gout (P > .05). A significant dose-response relationship was evident between the number of medical comorbidities and the prevalence of depression (OR = 1.18; 95% CI = 1.13-1.22).

CONCLUSION

Late-life depressive symptoms are significantly associated with several medical morbidities, and there appears to be a cumulative effect of the number of somatic diseases on the prevalence of depression. These findings augment the evidence for a complex relationship between mental and physical health in an otherwise healthy older population and might guide clinicians toward early recognition of high-risk individuals. J Am Geriatr Soc 68:1834-1841, 2020.

Has the sun set for seasonal affective disorder and HPA axis studies? A systematic review and future prospects

OBJECTIVE

Seasonal Affective Disorder (SAD) is a form of cyclic mood disorder that tends to manifest as winter depression. SAD has anecdotally been described as a hypocortisolemic condition. However, there are no systematic reviews on SAD and Hypothalamic-Pituitary-Adrenal (HPA) axis function. This review intends to summarize these findings.

METHODS

Using the PRISMA (2009) guideline recommendations we searched for relevant articles indexed in databases including MEDLINE, EMBASE, PsycINFO, and PsychArticles. The following keywords were used: "Seasonal affective disorder", OR "Winter Depression", OR "Seasonal depression" associated with: "HPA Axis" OR "cortisol" OR "CRH" OR "ACTH".

RESULTS

Thirteen papers were included for qualitative analysis. Studies used both heterogeneous methods and populations. The best evidence comes from a recent study showing that SAD patients tend to demonstrate an attenuated Cortisol Awakening Response (CAR) in winter, but not in summer, compared to controls. Dexamethasone Suppression Test (DST) studies suggest SAD patients have normal suppression of the HPA axis.

CONCLUSION

There is still insufficient evidence to classify SAD as a hypocortisolemic condition when compared to controls. Heterogeneous methods and samples did not allow replication of results. We discuss the limitations of these studies and provide new methods and targets to probe HPA axis function in this population. SAD can provide a unique window of opportunity to study HPA axis in affective disorders, since it is highly predictable and can be followed before, during and after episodes subsides.

Prevalence of depressive symptoms and its associated factors among healthy community-dwelling older adults living in Australia and the United States

OBJECTIVE

This study was conducted to estimate prevalence rates and factors associated with depressive symptoms indexed by the Centre for Epidemiological Studies-Depression (CES-D-10) score in a large sample of community-dwelling healthy older adults from Australia and the United States. Convergent and divergent validity of the CES-D-10 were also examined.

METHODS

A total of 19 114 individuals aged greater than or equal to 65 years old were enrolled from a primary prevention clinical trial. Depressive symptoms were classified using the CES-D-10 score greater than or equal to 8 and greater than or equal to 10. Gender-specific prevalence for subgroups according to sociodemographic characteristics were reported, and factors associated with depressive symptoms were estimated.

RESULTS

The overall prevalence rates of depressive symptoms were 9.8%, 95% CI, 8.5-11.2 and 5.0%, 95% CI, 4.0-6.0, according to the CES-D-10 score greater than or equal to 8 and greater than or equal to 10, respectively. Depressive symptoms were more common in women, individuals with less than 12 years of education, those living alone or in a residential care, ethnic minorities, current smokers, and former alcohol users. Convergent and divergent validities of the CES-D-10 were confirmed by observing strong negative association with the SF-12 mental health component and a modest negative association with SF-12 physical component, respectively.

CONCLUSIONS

This study reports the prevalence of depressive symptoms in Australian and US community-dwelling healthy older populations. These findings emphasize the high burden of the condition and factors associated with depressive symptoms, to better inform clinicians and help with early detection and treatment of depression in this age group.

Association Between Statin Use and Depressive Symptoms in a Large Community-Dwelling Older Population Living in Australia and the USA: A Cross-Sectional Study

BACKGROUND

Statin use has been frequently associated with depressive symptoms in an older population. However, the nature of this association is uncertain in the literature. In this study, we aimed to investigate the association of statin intake and the prevalence of depressive symptoms in healthy community-dwelling older adults living in Australia and the USA.

METHODS

We analysed baseline data from 19,114 participants, over 70 years of age (over 65 years of age, if from an ethnic minority). The association of self-reported statin use and prevalence of depressive symptoms, as measured by a validated depression scale [Center for Epidemiological Studies Depression Scale (CES-D 10)], was determined using logistic regression models. Multivariable logistic models were implemented to account for important demographics and other lifestyle and socioeconomic factors, such as sex, age, living status, education and smoking history.

RESULTS

A total of 5987 individuals were statin users. Of those, 633 (10.6%) had depressive symptoms (CES-D 10 cut-off ≥ 8), compared with 1246 (9.5%) of the non-statin users. In the unadjusted model, statin use was associated with an increase in prevalence of depressive symptoms (odds ratio 1.13, confidence interval 1.02-1.25, p = 0.02). However, after adjusting for important demographic and socioeconomic factors, the use of statins was not significantly associated with depressive symptoms (odds ratio 1.09, confidence interval 0.98-1.20, p = 0.11). In secondary analyses, only simvastatin was marginally associated with an increased prevalence of depressive symptoms. Statins were associated with a decreased prevalence of depressive symptoms in individuals with severe obesity (body mass index > 35 kg/m²) and an increased prevalence in participants between 75 and 84 years of age.

CONCLUSION

This study in a large community-dwelling older population did not show any association of statins with late-life depressive symptoms, after accounting for important socioeconomic and demographic factors. Confounding by indication is an important issue to be addressed in future pharmacoepidemiologic studies of statins.

Co-occurrence of depression with chronic diseases among the older population living in low- and middle-income countries: A compound health challenge

BACKGROUND

Few studies have examined the associations between mental and physical health conditions in low- and middle-income countries (LMICs). The aim of this study was to evaluate comorbidity of depression and other chronic diseases in community-dwelling older adults.

METHODS

Data were obtained from the World Health Organization Study on global AGEing and adult health (SAGE) implemented in 6 LMICs: China, Ghana, India, Mexico, the Russian Federation, and South Africa. A total of 33,508 participants age ≥50 were included in this analysis. Demographics, socioeconomic status, anthropometrics, depression, and chronic diseases status were collected using well-validated instruments in all countries. Multivariate analyses were used to examine the association between depression and comorbid conditions.

RESULTS

Type 2 diabetes mellitus (odds ratio: 1.39 [95% confidence interval: 1.15, 1.68]), arthritis (1.82 [1.52, 2.18]), asthma (3.20 [2.56, 4.00]), chronic lung disease (3.77 [3.08, 4.62]), angina (2.48 [2.01, 3.05]), and stroke (2.74 [2.18, 3.45]) were positively associated with depression prevalence (all P < .001).

CONCLUSIONS

Noting the strong association between depression and other chronic diseases in our sample of older adults from 6 LMICs, additional vigilance and screening through informal and formal health care systems would help to decrease the impact of comorbidity on the health and well-being of older populations.

Neurobiology and Therapeutic Potential of Cyclooxygenase-2 (COX-2) Inhibitors for Inflammation in Neuropsychiatric Disorders

Neuropsychiatric disorders, such as depression, bipolar disorder, schizophrenia, obsessive-compulsive disorder, and neurodevelopmental disorders such as autism spectrum disorder, are associated with significant illness burden. Accumulating evidence supports an association between these disorders and inflammation. Consequently, anti-inflammatory agents, such as the cyclooxygenase-2 inhibitors, represent a novel avenue to prevent and treat neuropsychiatric illness. In this paper, we first review the role of inflammation in psychiatric pathophysiology including inflammatory cytokines' influence on neurotransmitters, the hypothalamic-pituitary-adrenal axis, and microglial mechanisms. We then discuss how cyclooxygenase-2-inhibitors influence these pathways with potential therapeutic benefit, with a focus on celecoxib, due to its superior safety profile. A search was conducted in PubMed, Embase, and PsychINFO databases, in addition to Clinicaltrials.gov and the Stanley Medical Research Institute trial registries. The results were presented as a narrative review. Currently available outcomes for randomized controlled trials up to November 2017 are also discussed. The evidence reviewed here suggests cyclooxygenase-2 inhibitors, and in particular celecoxib, may indeed assist in treating the symptoms of neuropsychiatric disorders; however, further studies are required to assess appropriate illness stage-related indication.

Statins and Inflammation: New Therapeutic Opportunities in Psychiatry

Statins, which are widely used to treat hypercholesterolemia, have anti-inflammatory and anti-oxidant effects. These are thought to be responsible for the potential effects of statins on various psychiatric disorders. In this study, we comprehensively review the literature to investigate the effects of statins on various psychiatric disorders including depression, schizophrenia, and dementia. In addition, we review adverse effects and drug interactions of statins to give clinically useful information guiding statin use in the psychiatric field. Statins seem useful in reducing depression, particularly in patients with physical disorders such as cardiovascular disease. In patients with schizophrenia, negative symptoms may be reduced by adjuvant statin therapy. Studies on cohorts at risk for dementia have generally shown protective effects of statins, while those on treatment for dementia show inconsistent results. In conclusion, statins used in combination with conventional psychotropic medications may be effective for various psychiatric disorders including depression, schizophrenia, and dementia. Further study is required to determine optimal doses and duration of statin use for the treatment of psychiatric disorders.

Atypical depression and non-atypical depression: Is HPA axis function a biomarker? A systematic review

BACKGROUND

The link between the abnormalities of the Hypothalamic-pituitary-adrenal (HPA) axis and depression has been one of the most consistently reported findings in psychiatry. At the same time, multiple studies have demonstrated a stronger association between the increased activation of HPA-axis and melancholic, or endogenous depression subtype. This association has not been confirmed for the atypical subtype, and some researchers have suggested that as an antinomic depressive subtype, it may be associated with the opposite type, i.e. hypo-function, of the HPA-axis, similarly to PTSD. The purpose of this systematic review is to summarise existing studies addressing the abnormalities of the HPA-axis in melancholic and/or atypical depression.

METHOD

We conducted a systematic review in the literature by searching MEDLINE, PsycINFO, OvidSP and Embase databases until June 2017. The following search items were used: "hypothalamic-pituitary-adrenal" OR "HPA" OR "cortisol" OR "corticotropin releasing hormone" OR "corticotropin releasing factor" OR "glucocorticoid*" OR "adrenocorticotropic hormone" OR "ACTH" AND "atypical depression" OR "non-atypical depression" OR "melancholic depression" OR "non-melancholic depression" OR "endogenous depression" OR "endogenomorphic depression" OR "non-endogenous depression". Search limits were set to include papers in English or German language published in peer-reviewed journals at any period. All studies were scrutinized to determine the main methodological characteristics, and particularly possible sources of bias influencing the results reported.

RESULTS

We selected 48 relevant studies. Detailed analysis of the methodologies used in the studies revealed significant variability especially regarding the samples' definition comparing the HPA axis activity of melancholic patients to atypical depression, including healthy controls. The results were subdivided into 4 sections: (1) 27 studies which compared melancholic OR endogenous depression vs. non-melancholic or non-endogenous depression or controls; (2) 9 studies which compared atypical depression or atypical traits vs. non-atypical depression or controls; (3) 7 studies which compared melancholic or endogenous and atypical depression subtypes and (4) 5 studies which used a longitudinal design, comparing the measures of HPA-axis across two or more time points. While the majority of studies did confirm the association between melancholic depression and increased post-challenge cortisol levels, the association with increases in basal cortisol and basal ACTH were less consistent. Some studies, particularly those focusing on reversed vegetative symptoms, demonstrated a decrease in the activity of the HPA axis in atypical depression compared to controls, but the majority did not distinguish it from healthy controls.

CONCLUSIONS

In conclusion, our findings indicate that there is a difference in the activity of the HPA-axis between melancholic and atypical depressive subtypes. However, these are more likely explained by hypercortisolism in melancholia; and most often normal than decreased function in atypical depression. Further research should seek to distinguish a particular subtype of depression linked to HPA-axis abnormalities, based on symptom profile, with a focus on vegetative symptoms, neuroendocrine probes, and the history of adverse childhood events. New insights into the dichotomy addressed in this review might be obtained from genetic and epigenetic studies of HPA-axis related genes in both subtypes, with an emphasis on the presence of vegetative symptoms.

A translational approach to clinical practice via stress-responsive glucocorticoid receptor signaling

A recent article by Kwan and colleagues could elegantly demonstrate the necessary interaction between neuronal serotonin (5-HT) systems and the hypothalamic-pituitary-adrenal (HPA) axis through glucocorticoid receptors (GR), producing an adequate stress response, in this case, responding to hypoxia with an increase in hematopoietic stem and progenitor cells (HSPC). There is an intricate system connecting brain, body and mind and this exchange is only possible when all these systems-nervous, endocrine, and immune-have receptors on critical cells to receive information (via messenger molecules) from each of the other systems. There is evidence that the expression and function of GR in the hippocampus, mainly MR, is regulated by the stimulation of 5-HT receptors. Stressful stimuli increase 5-HT release and turnover in the hippocampus, and it seems reasonable to suggest that some of the changes in mineralocorticoid and GR expression may be mediated, in part at least, by the increase in 5-HT. Also serotonin and HPA axis dysfunctions have already been implicated in a variety of psychiatric disorders, especially depression. Early life stress (ELS) can have profound impact on these systems and can predispose subjects to a variety of adult metabolic and psychiatric conditions. It is important to analyze the mechanisms of this complex interaction and its subsequent programming effects on the stress systems, so that we can find new ways and targets for treatment of psychiatric disorders. Different areas of research on basic biological sciences are now being integrated and this approach will hopefully provide several new insights, new pharmacological targets and improve our global understanding of these highly debilitating chronic conditions, that we now call mental disorders.