High cortisol levels in the offspring of parents with bipolar disorder during two weeks of daily sampling

Putative Risk Biomarkers of Bipolar Disorder in At-risk Youth

Bipolar disorder is a highly heritable and functionally impairing disease. The recognition and intervention of BD especially that characterized by early onset remains challenging. Risk biomarkers for predicting BD transition among at-risk youth may improve disease prognosis. We reviewed the more recent clinical studies to find possible pre-diagnostic biomarkers in youth at familial or (and) clinical risk of BD. Here we found that putative biomarkers for predicting conversion to BD include findings from multiple sample sources based on different hypotheses. Putative risk biomarkers shown by perspective studies are higher bipolar polygenetic risk scores, epigenetic alterations, elevated immune parameters, front-limbic system deficits, and brain circuit dysfunction associated with emotion and reward processing. Future studies need to enhance machine learning integration, make clinical detection methods more objective, and improve the quality of cohort studies.

The Mood and Resilience in Offspring (MARIO) project: a longitudinal cohort study among offspring of parents with and without a mood disorder

BACKGROUND

One of the most robust risk factors for developing a mood disorder is having a parent with a mood disorder. Unfortunately, mechanisms explaining the transmission of mood disorders from one generation to the next remain largely elusive. Since timely intervention is associated with a better outcome and prognosis, early detection of intergenerational transmission of mood disorders is of paramount importance. Here, we describe the design of the Mood and Resilience in Offspring (MARIO) cohort study in which we investigate: 1. differences in clinical, biological and environmental (e.g., psychosocial factors, substance use or stressful life events) risk and resilience factors in children of parents with and without mood disorders, and 2. mechanisms of intergenerational transmission of mood disorders via clinical, biological and environmental risk and resilience factors.

METHODS

MARIO is an observational, longitudinal cohort study that aims to include 450 offspring of parents with a mood disorder (uni- or bipolar mood disorders) and 100-150 offspring of parents without a mood disorder aged 10-25 years. Power analyses indicate that this sample size is sufficient to detect small to medium sized effects. Offspring are recruited via existing Dutch studies involving patients with a mood disorder and healthy controls, for which detailed clinical, environmental and biological data of the index-parent (i.e., the initially identified parent with or without a mood disorder) is available. Over a period of three years, four assessments will take place, in which extensive clinical, biological and environmental data and data on risk and resilience are collected through e.g., blood sampling, face-to-face interviews, online questionnaires, actigraphy and Experience Sampling Method assessment. For co-parents, information on demographics, mental disorder status and a DNA-sample are collected.

DISCUSSION

The MARIO cohort study is a large longitudinal cohort study among offspring of parents with and without mood disorders. A unique aspect is the collection of granular data on clinical, biological and environmental risk and resilience factors in offspring, in addition to available parental data on many similar factors. We aim to investigate the mechanisms underlying intergenerational transmission of mood disorders, which will ultimately lead to better outcomes for offspring at high familial risk.

Hair cortisol concentrations and perceived stress in 7-year-old children at familial high-risk of schizophrenia or bipolar disorder

BACKGROUND

Dysregulation of the HPA-axis, perceived stress and interpersonal trauma are associated with an elevated risk for schizophrenia and bipolar disorder. Being at familial high-risk of these two mental disorders also constitutes an increased risk. In this study, we aimed to investigate hair cortisol concentrations and perceived stress among 7-year-old children at familial high-risk of schizophrenia (FHR-SZ), bipolar disorder (FHR-BP), and population-based controls (controls).

METHODS

A total of 515 children (mean age 7.8, SD 0.2) from baseline assessment of the Danish High Risk and Resilience Study - VIA 7 participated in this study. Hair cortisol concentrations were analyzed among 322 children (FHR-SZ; N = 111, FHR-BP; N = 82, controls; N = 129). Perceived stress was assessed with the Daily Life Stressor Scale including 512 children (FHR-SZ; N = 195, FHR-BP; N = 118, controls; N = 199). Interpersonal trauma was measured with face-to-face interviews.

RESULTS

Seven-year-old children at FHR-SZ or FHR-BP did not have a higher level of hair cortisol concentrations compared with controls (FHR-SZ: mean: 5.10, 95%CI 3.69-6.52; FHR-BP: mean: 5.01, 95%CI 3.27-6.72; controls: mean: 4.51, 95%CI 3.61-5.40; p = 0.77). Self-reported perceived stress was higher among children at FHR-SZ and FHR-BP compared with controls (FHR-SZ: mean: 12.09, 95%CI 10.99-13.19; FHR-BP: mean: 10.69, 95%CI 9.38-11.99; controls: mean: 8.90, 95%CI 8.13-9.68; p < 0.001). There was no significant association between hair cortisol concentrations and perceived stress (p = 0.84). Exploratory analyses revealed that interpersonal trauma exposure was neither associated with elevated hair cortisol nor perceived stress.

CONCLUSIONS

Children at FHR-SZ and FHR-BP did not exhibit higher levels of hair cortisol concentrations at age 7, while both FHR-groups had higher level of self-reported perceived stress compared with controls. Early attention to stress in children at FHR is crucial and these vulnerabilities should be targeted in future interventions studies.

Shared postulations between bipolar disorder and polycystic ovary syndrome pathologies

INTRODUCTION

Women with bipolar disorder (BD) present a high prevalence of polycystic ovary syndrome (PCOS) and other reproductive disorders even before diagnosis or treatment of the disease. Postulations on the potential molecular mechanisms of comorbid PCOS in women with BD remain limited to influence of medications and need further extension.

OBJECTIVES

This review focuses on evidence suggesting that common metabolic and immune disorders may play an important role in the development of BD and PCOS.

RESULTS

The literature covered in this review suggests that metabolic and immune disorders, including the dysfunction of the hypothalamic-pituitary-adrenal axis, chronic inflammatory state, gut microbial alterations, adipokine alterations and circadian rhythm disturbance, are observed in patients with BD and PCOS. Such disorders may be responsible for the increased prevalence of PCOS in the BD population and indicate a susceptibility gene overlap between the two diseases. Current evidence supports postulations of common metabolic and immune disorders as endophenotype in BD as well as in PCOS.

CONCLUSIONS

Metabolic and immune disorders may be responsible for the comorbid PCOS in the BD population. The identification of hallmark metabolic and immune features common to these two diseases will contribute to the clarification of the effect of BD on the reproductive endocrine function and development of symptomatic treatments targeting the biomarkers of the two diseases.

Blue Light Blocking Treatment for the Treatment of Bipolar Disorder: Directions for Research and Practice

Recent results from a small number of clinical studies have resulted in the suggestion that the process of blocking the transmission of shorter-wavelength light (‘blue light’ with a wave length of 450 nm to 470 nm) may have a beneficial role in the treatment of bipolar disorder. This critical review will appraise the quality of evidence so far as to these claims, assess the neurobiology that could be implicated in the underlying processes while introducing a common set of research criteria for the field.

Basal and reactive cortisol: A systematic literature review of offspring of parents with depressive and bipolar disorders

One of the most consistent biological findings in the study of affective disorders is that those with depression commonly show abnormal cortisol response, which suggests dysregulation of the hypothalamic-pituitary-adrenal (HPA) axis. Children of parents with mood disorders offer the opportunity to explore the biological pathways that may confer risk for psychopathology. This review explores basal and reactive cortisol in the offspring of parents who are currently depressed or have had a history of a depressive or bipolar disorder. Using PRISMA guidelines, search terms yielded 2002 manuscripts. After screening, 87 of these manuscripts were included. Results from the literature suggest that while the degree and direction of dysregulation varies, offspring of a parent with depression tend to show elevations in both basal (particularly morning and evening) and reactive (tentatively for social stressors) cortisol levels. There were few studies focused on offspring of parents with bipolar disorder. This review also discusses implications and recommendations for future research regarding the HPA axis in the intergenerational transmission of depressive disorders.

The Neurobiology of Bipolar Disorder

Bipolar disorders are severe and have a high prevalence; despite this, the neurobiological mechanisms are far from being elucidated, and this limits the development of new treatments. Although the aetiology of bipolar disorders is not yet fully understood, it is accepted that the disorder(s) may result from the interaction between genetic factors that cause susceptibility and predisposing, precipitating and perpetuating environmental factors, such as stress and traumatic events. A pathophysiological formulation of the disease suggests that dysfunctions in intracellular biochemical cascades, oxidative stress and mitochondrial dysfunction impair the processes linked to neuronal plasticity, leading to cell damage and the consequent loss of brain tissue that has been identified in post-mortem and neuroimaging studies. The data we have reviewed suggests that peripheral biomarkers related to hormones, inflammation, oxidative stress and neurotrophins are altered in bipolar disorders, especially during acute mood episodes. Together, these changes have been associated with a systemic toxicity of the disease and the damage resulting from multiple episodes. Systemic toxicity related to recurrent episodes in bipolar disorder may influence brain anatomical changes associated with the progression of stress and neuroplasticity in bipolar disorder and the response to treatment.

Prevalence and correlates of bipolar spectrum disorders in Singapore: Results from the 2016 Singapore Mental Health Study (SMHS 2016)

BACKGROUND

Prevalence estimates of Bipolar Spectrum Disorders (BSD) remain scant in Southeast Asia. This study aims to investigate the prevalence of BSD, its correlates with sociodemographic factors, and the associations between the BSD subgroups and clinical severity, impairment, and disability in Singapore.

METHODS

This study utilizes data gathered from the second Singapore Mental Health Study (SMHS)- a nationwide cross-sectional survey conducted between 2016 and 2018 (response rate: 69.5%). Respondents were randomly selected and administered, in a single visit, interviewer-led surveys of the World Health Organization Composite International Diagnostic Interview version 3.0 (CIDI 3.0) in their preferred language (i.e. Chinese, Malay, Tamil, or English). A total of 6126 residents completed the study.

RESULTS

The lifetime weighted prevalence of BSD, Bipolar I, II, and subthreshold bipolar disorder was 3.1%, 1.5%, 0.03%, and 1.6% respectively. A higher prevalence of Bipolar Disorders (BPD) was significantly associated with younger age, being divorced or separated, and being unemployed. Lifetime comorbidity of BSD with at least one other psychiatric or physical condition was 45% and 51% respectively. BSD was most comorbid with Obsessive Compulsive Disorder (psychiatric condition) and Chronic pain (physical condition).

LIMITATIONS

This study relies on self-report data which may be subject to unintended response biases leading to the under or over-reporting of results.

DISCUSSION

In addition to the high prevalence of BPD, there is also a concerning shift and increase in the proportion of those who experience severe symptoms of mania/hypomania and depression. Subthreshold bipolar disorder is found to be clinically significant and cross-culturally valid in a multi-cultural setting.

Peripheral Oxidative Stress Markers in Patients with Bipolar Disorder during Euthymia and in Siblings

AIMS

Oxidative stress is increased during the acute phases of bipolar disorder (BD). Our aim here was to analyze oxidative stress biomarkers in patients with BD during euthymia and their siblings.

METHOD

A cross-sectional study was performed in euthymic patients with BD-I (n=48), unaffected siblings (n=23) and genetically unrelated healthy controls (n=21). Protein carbonyl content (PCC), total antioxidant capacity (TRAP), lipid peroxidation (TBARS) and uric acid were measured as biomarkers of oxidative stress in blood.

RESULTS

The antioxidant capacity (TRAP) was lower (p<0.001) in patients with BD compared to their siblings and controls, whereas no differences were observed in PCC, TBARS or uric acid. In patients, the concentrations of TRAP and TBARS were positively associated with the dose of valproic acid (p<0.05 and p<0.001, respectively). The concentrations of these biomarkers were not significantly associated with any of socio-demographic and clinical variables.

CONCLUSION

A selective reduction in antioxidant capacity is present in BD during euthymia state, whereas other markers of oxidative stress are unaltered during euthymia. Siblings did not show any alterations in oxidative stress biomarkers. Oxidative stress might represent a state-dependent marker in BD. The association between treatment with valproic acid and oxidative stress markers in euthymia deserves further studies.

Hair cortisol in newly diagnosed bipolar disorder and unaffected first-degree relatives

OBJECTIVE

Hair cortisol is a promising new biomarker of retrospective systemic cortisol concentration. In this study, we compared hair cortisol concentrations in patients with newly diagnosed bipolar disorder (BD), their unaffected first-degree relatives and healthy individuals and identified potential predictors of hair cortisol concentrations in patients with BD.

METHOD

In a cross-sectional design, we compared hair cortisol concentrations in 181 patients with newly diagnosed/first episode BD, 42 of their unaffected first-degree relatives and 101 healthy age- and sex-matched individuals with no personal or first-degree family history of affective disorder. In patients with BD, we further investigated whether medication- and illness related variables, as well as measures of stressful life events in the preceding 12 months and childhood trauma, were associated with hair cortisol concentrations.

RESULTS

Hair cortisol concentrations were 35.1% (95%CI: 13.0-61.5) higher in patients with BD (P = 0.001) compared with healthy individuals in models adjusted for age and sex. Hair cortisol concentrations in unaffected first-degree relatives did not differ from healthy individuals (P = 0.8). In patients, neither medication, illness duration nor stress related variables were associated with hair cortisol concentrations.

CONCLUSION

We found elevated hair cortisol concentrations in patients newly diagnosed with BD indicating the presence of physiological stress in early stages of BD.

Offspring of parents with mood disorders: time for more transgenerational research, screening and preventive intervention for this high-risk population

PURPOSE OF REVIEW

Offspring of parents with mood disorders (major depressive and bipolar disorder) are at increased risk for developing mood disorders. In this review, an overview regarding the intergenerational transmission of mood disorders, screening, and preventive intervention is given for this vulnerable group.

RECENT FINDINGS

Offspring of parents with depression have a 40% chance of developing a depression, whereas offspring of parents with bipolar disorder have a 10% chance of developing a bipolar disorder by adulthood. Studies into the intergenerational transmission of mood disorders show that children of parents with mood disorders have increased biological dysregulation and neuropsychosocial impairments. Although there is a clear need for early identification of those at the highest risk, there are few systematic attempts in mental health care to screen children of parents with mood disorders. Lastly, preventive interventions seem to be effective in reducing depressive symptoms of children of parents with depression; however, those effects are small and short-lived.

SUMMARY

Offspring of parents with mood disorders constitute a vulnerable group at high risk of mood disorders. More research needs to be conducted regarding mechanisms of the intergenerational transmission. Moreover, screening and preventive interventions for these offspring should be systematically evaluated and implemented.

BDNF and BMI effects on brain structures of bipolar offspring: results from the global mood and brain science initiative

OBJECTIVE

To compare brain-derived neurotrophic factor (BDNF) levels between offspring of individuals with bipolar disorders (BD) and healthy controls (HCs) and investigate the effects of BDNF levels and body mass index (BMI) on brain structures.

METHOD

Sixty-seven bipolar offspring and 45 HCs were included (ages 8-28). Structural images were acquired using 3.0 Tesla magnetic resonance imaging. Serum BDNF levels were measured using enzyme-linked immunosorbent assay. Multivariate and univariate analyses of covariance were conducted.

RESULTS

Significantly higher BDNF levels were observed among bipolar offspring, relative to HCs (P > 0.025). Offspring status moderated the association between BDNF and BMI (F₁ =4.636, P = 0.034). After adjustment for relevant covariates, there was a trend for a significant interaction of group and BDNF on neuroimaging parameters (Wilks'λ F_56,94 =1.463, P = 0.052), with significant effects on cerebellar white matter and superior and middle frontal regions. Brain volume and BDNF were positively correlated among HCs and negatively correlated among bipolar offspring. Interactions between BDNF and BMI on brain volumes were non-significant among HCs (Wilks'λ F_28,2 =2.229, P = 0.357), but significant among bipolar offspring (Wilks'λ F_28,12 =2.899, P = 0.028).

CONCLUSION

Offspring status and BMI moderate the association between BDNF levels and brain structures among bipolar offspring, underscoring BDNF regulation and overweight/obesity as key moderators of BD pathogenesis.

CORTISOL LEVELS AND SUICIDE IN BIPOLAR I DISORDER

CONTEXT

Hypothalamic-pituitary-adrenal (HPA) axis irregularities have been described both in bipolar disorder and suicidal behaviour, but few studies have examined the relationship between suicidal behaviours and cortisol levels in bipolar disorder.

OBJECTIVE

We compared HPA axis activity in bipolar I (BPD I) individuals with and without suicidal ideation and behaviour through multiple measurement of serum and salivary cortisol.

DESIGN

Cross-sectional, observational study.

SUBJECTS AND METHODS

75 BPD I patients were assigned into 3 groups (no history of suicidal behaviour, history of suicidal ideation, history of suicide attempt), according to the C-SSRS. Socio-demographical and clinical data was obtained by using MINI 6.0 and a semi-structured questionnaire. Salivary samples were collected using Sarstedt Cortisol Salivette synthetic swab system for two consecutive days at 08:00, 16:00, 23:00 and salivary cortisol concentrations were determined by ELISA technique. A unique 1mg dose of dexamethasone was administered on the first day, at 23:00, after the collection of the saliva sample. Blood was collected on the first day at 8:00 AM and basal morning serum cortisol levels were determined by immunoassay with fluorescence detection.

RESULTS

Cortisol parameters in our BPD I sample did not vary significantly in respect to suicidal history. However, patients with a history of suicidal ideation have significantly higher total cortisol outputs than patients with no history of suicidal behaviour in the 18 to 40 age category compared with the above 40 age category.

CONCLUSIONS

Total cortisol daily output varies significantly in an age-dependent manner in respect to suicidal thoughts in BPD I individuals.

Integrated transcriptome and methylome analysis in youth at high risk for bipolar disorder: a preliminary analysis

First-degree relatives of patients with bipolar disorder (BD), particularly their offspring, have a higher risk of developing BD and other mental illnesses than the general population. However, the biological mechanisms underlying this increased risk are still unknown, particularly because most of the studies so far have been conducted in chronically ill adults and not in unaffected youth at high risk. In this preliminary study we analyzed genome-wide expression and methylation levels in peripheral blood mononuclear cells from children and adolescents from three matched groups: BD patients, unaffected offspring of bipolar parents (high risk) and controls (low risk). By integrating gene expression and DNA methylation and comparing the lists of differentially expressed genes and differentially methylated probes between groups, we were able to identify 43 risk genes that discriminate patients and high-risk youth from controls. Pathway analysis showed an enrichment of the glucocorticoid receptor (GR) pathway with the genes MED1, HSPA1L, GTF2A1 and TAF15, which might underlie the previously reported role of stress response in the risk for BD in vulnerable populations. Cell-based assays indicate a GR hyporesponsiveness in cells from adult BD patients compared to controls and suggest that these GR-related genes can be modulated by DNA methylation, which poses the theoretical possibility of manipulating their expression as a means to counteract the familial risk presented by those subjects. Although preliminary, our results suggest the utility of peripheral measures in the identification of biomarkers of risk in high-risk populations and further emphasize the potential role of stress and DNA methylation in the risk for BD in youth.

Telomere Length, Oxidative Stress, Inflammation and BDNF Levels in Siblings of Patients with Bipolar Disorder: Implications for Accelerated Cellular Aging

BACKGROUND

Growing evidence supports the existence of neurobiological trait abnormalities in individuals at genetic risk for bipolar disorder. The aim of this study was to examine potential differences in brain-derived neurotrophic factor, cytokines, oxidative stress, and telomere length markers between patients with bipolar disorder, their siblings, and healthy controls.

METHODS

Thirty-six patients with bipolar disorder type I, 39 siblings, and 44 healthy controls were assessed. Serum levels of brain-derived neurotrophic factor, interleukin-6, interleukin-10, tumor necrosis factor-α, C-C motif chemokine 11, C-C motif chemokine 24, and 3-nitrotyrosine were measured, as were the activities of glutathione peroxidase, glutathione reductase, and glutathione S-transferase. Telomere length (T/S ratio) was measured using quantitative polymerase chain reaction.

RESULTS

Telomere length was different between the 3 groups (P = .041) with both patients and siblings showing a shorter T/S ratio compared with healthy controls. Patients showed increased levels of interleukin-6 (P = .005) and interleukin-10 (P = .002) compared with controls as well as increased levels of interleukin-6 (p = 0.014) and CCL24 (P = .016) compared with their siblings. C-C motif chemokine 11 levels were increased in siblings compared with controls (P = .015), and a similar tendency was found in patients compared with controls (P = .045). Glutathione peroxidase activity was decreased in patients compared with controls (P = .006) and siblings (P = .025). No differences were found for the other markers.

CONCLUSIONS

The present results suggest that unaffected siblings may present accelerated aging features. These neurobiological findings may be considered as endophenotypic traits. Further prospective studies are warranted.

Childhood trauma and HPA axis functionality in offspring of bipolar parents

Children of a parent with bipolar disorder (bipolar offspring) have an increased risk for mood disorders. While genetic factors play a significant role in this population, susceptibility to environmental stress may also significantly contribute to this vulnerability for mood disorders. Childhood trauma has consistently been found to increase the risk for mood disorders, with persisting consequences for hypothalamic-pituitary-adrenal (HPA) axis functionality. However, it is currently unknown whether childhood trauma specifically affects HPA axis activity in individuals with a familial risk for bipolar disorder. Therefore, we investigated the effects of childhood trauma on daytime and evening cortisol levels and dexamethasone suppression in bipolar offspring (N=70) and healthy controls (N=44). In our study we found no significant differences in daytime and evening cortisol levels as well as dexamethasone suppression between bipolar offspring and healthy controls (all p-values>0.43). In contrast, childhood trauma differentially affected daytime cortisol levels in the bipolar offspring compared to healthy controls (childhood trauma X bipolar offspring interaction, β=-7.310, p=0.0414) with an effect of childhood trauma on daytime cortisol in bipolar offspring at trend level (p=0.058). In the bipolar offspring group, lifetime or current psychiatric diagnoses, and stressful life events separately did not affect cortisol levels or dexamethasone suppression (all p-values>p=0.50). These findings were independent of current or lifetime psychiatric diagnosis. In conclusion, trauma-related changes in daytime HPA axis activity appear to be a specific trait in bipolar offspring who have increased risk for mood disorders compared to healthy individuals.

Sleep and circadian alterations in people at risk for bipolar disorder: A systematic review

BACKGROUND

Sleep and circadian abnormalities have been mostly demonstrated in bipolar patients. However, it is not clear whether these alterations are present in population at high risk for bipolar disorder (BD), indicating a possible risk factor for this condition.

OBJECTIVE

This systematic review aims to define current evidence about sleep and rhythm alterations in people at risk for BD and to evaluate sleep and circadian disorders as risk factor for BD.

METHODS

The systematic review included all articles about the topic until February 2016. Two researchers performed an electronic search of PubMed and Cochrane Library. Keywords used were 'sleep' or 'rhythm' or 'circadian' AND 'bipolar disorder' or 'mania' or 'bipolar depression' AND 'high-risk' or 'risk'.

RESULTS

Thirty articles were analyzed (7451 participants at risk for BD). Sleep disturbances are frequent in studies using both subjective measures and actigraphy. High-risk individuals reported irregularity of sleep/wake times, poor sleep and circadian rhythm disruption. Poor sleep quality, nighttime awakenings, and inadequate sleep are possible predictive factors for BD. A unique study suggested that irregular rhythms increase risk of conversion. People at risk for BD showed high cortisol levels in different times of day. Studies about anatomopathology, melatonin levels, inflammatory cytokines and oxidative stress were not identified. The most important limitations were differences in sleep and rhythm measures, heterogeneity of study designs, and lack of consistency in the definition of population at risk.

CONCLUSION

Sleep and circadian disturbances are common in people at risk for BD. However, the pathophysiology of these alterations and the impact on BD onset are still unclear.

Immuno-psychiatry: an agenda for clinical practice and innovative research

BACKGROUND

The diagnostic scheme for psychiatric disorders is currently based purely on descriptive nomenclature given that biomarkers subtypes and clearly defined causal mechanisms are lacking for the vast majority of disorders. The emerging field of "immuno-psychiatry" has the potential to widen the exploration of a mechanism-based nosology, possibly leading to the discovery of more effective personalised treatment strategies.

DISCUSSION

Disturbances in immuno-inflammatory and related systems have been implicated in the aetiology, pathophysiology, phenomenology and comorbidity of several psychiatric disorders, including major mood disorders and schizophrenia. A fundamental challenge in their clinical management is to identify bio-signatures that might indicate risk, state, trait, prognosis or theragnosis. Here, we provide the rationale for a clinical and research agenda to refine future clinical practice and conceptual views, and to delineate pathways toward innovative treatment discovery.

CONCLUSION

The development of bio-signatures will allow clinicians to tailor interventions to the abovementioned biomarker subtypes - a major translational goal for research in this field.

Molecular circadian rhythm shift due to bright light exposure before bedtime is related to subthreshold bipolarity

This study examined the link between circadian rhythm changes due to bright light exposure and subthreshold bipolarity. Molecular circadian rhythms, polysomnography, and actigraphy data were studied in 25 young, healthy male subjects, divided into high and low mood disorder questionnaire (MDQ) score groups. During the first 2 days of the study, the subjects were exposed to daily-living light (150 lux) for 4 hours before bedtime. Saliva and buccal cells were collected 5 times a day for 2 consecutive days. During the subsequent 5 days, the subjects were exposed to bright light (1,000 lux), and saliva and buccal cell samples were collected in the same way. Molecular circadian rhythms were analyzed using sine regression. Circadian rhythms of cortisol (F = 16.956, p < 0.001) and relative PER1/ARNTL gene expression (F = 122.1, p < 0.001) showed a delayed acrophase in both groups after bright light exposure. The high MDQ score group showed a significant delay in acrophase compared to the low MDQ score group only in salivary cortisol (F = 8.528, p = 0.008). The high MDQ score group showed hypersensitivity in cortisol rhythm shift after bright light exposure, suggesting characteristic molecular circadian rhythm changes in the high MDQ score group may be related to biological processes downstream from core circadian clock gene expression.

Perceived stress and hair cortisol: Differences in bipolar disorder and schizophrenia

INTRODUCTION

Bipolar disorder (BD) and schizophrenia (SCZ) are psychiatric disorders with shared and distinct clinical and genetic features. In both disorders, stress increases the risk for onset or relapse and dysregulation of the hypothalamus-pituitary-adrenal (HPA) axis has been reported. The latter is frequently investigated by measuring changes in the hormonal end product of the HPA axis, i.e., the glucocorticoid cortisol, whose concentration exhibits diurnal variation. The analysis of hair cortisol concentration (HCC) is a new method, which allows assessment of cumulative cortisol secretion over the preceding three months.

AIMS

To explore whether perceived stress and HCC: (i) differ between BD patients, SCZ patients, and controls; (ii) change over disease course; and iii) are associated with an increased genetic risk for BD or SCZ.

METHODS

159 SCZ patients, 61 BD patients and 82 controls were included. Assessment included psychopathology, perceived stress, and HCC. Inpatients with an acute episode (38 BD and 77 SCZ) were assessed shortly after admission to hospital and at 3 and 6 months follow-up. Outpatients in remission and controls were assessed at one time point only. Polygenic risk scores for BD and SCZ were calculated based on results of the Psychiatric Genomic Consortium.

RESULTS

(i) Perceived stress was higher in BD and SCZ patients compared to controls (p<0.02), and was lower in outpatients in remission compared to inpatients on admission. HCC was higher in BD patients compared to SCZ patients and controls (p<0.02), and higher in inpatients on admission than in outpatients in remission (p=0.0012). In BD patients (r=0.29; p=0.033) and SCZ patients (r=0.20; p=0.024) manic symptoms were correlated with HCC. (ii) In both BD and SCZ inpatients, perceived stress decreased over the 6 month study period (p=0.048), while HCC did not change significantly over the 6 month study period. (iii) In controls, but not in the patient groups, the genetic risk score for BD was associated with HCC (r=0.28, p=0.023).

CONCLUSIONS

While our results are consistent with previous reports of increased perceived stress in BD and SCZ, they suggest differential involvement of the HPA axis in the two disorders. The genetic study supports this latter finding, and suggests that this effect is present below the threshold of manifest disorder.

Repeated salivary daytime cortisol and onset of mood episodes in offspring of bipolar parents

Background

Differences in cortisol secretion may differentiate individuals at high compared to low genetic risk for bipolar disorder (BD) and predict the onset or recurrence of mood episodes. The objectives of this study were to determine if salivary cortisol measures are: (1) different in high-risk offspring of parents with BD (HR) compared to control offspring of unaffected parents (C), (2) stable over time, (3) associated with the development of mood episode onset/recurrence, and (4) influenced by comorbid complications.

Methods

Fifty-three HR and 22 C completed salivary cortisol sampling annually for up to 4 years in conjunction with semi-structured clinical interviews. The cortisol awakening response (CAR), daytime cortisol [area under the curve (AUC)], and evening cortisol (8:00 p.m.) were calculated.

Results

There were no differences in baseline CAR, AUC and evening cortisol between HR and C (p = 0.38, p = 0.30 and p = 0.84), respectively. CAR, AUC and evening cortisol were stable over yearly assessments in HR, while in Cs, evening cortisol increased over time (p = 0.008), and CAR and AUC remained stable. In HR, AUC and evening cortisol increased the hazard of a new onset mood disorder/recurrence by 2.7 times (p = 0.01), and 3.5 times (p = 0.01), respectively, but this was no longer significant after accounting for multiple comparisons.

Conclusions

Salivary cortisol is stable over time within HR offspring. However, between individuals, basal salivary cortisol is highly variable. More research is needed, with larger samples of prospectively studied HR youth using a more reliable method of cortisol measurement, to determine the potential role of cortisol in the development of mood disorders.

Electronic supplementary material

The online version of this article (doi:10.1186/s40345-016-0053-5) contains supplementary material, which is available to authorized users.

The underlying neurobiology of key functional domains in young people with mood and anxiety disorders: a systematic review

BACKGROUND

Mood and anxiety disorders are leading causes of disability and mortality, due largely to their onset during adolescence and young adulthood and broader impact on functioning. Key factors that are associated with disability and these disorders in young people are social and economic participation (e.g. education, employment), physical health, suicide and self-harm behaviours, and alcohol and substance use. A better understanding of the objective markers (i.e. neurobiological parameters) associated with these factors is important for the development of effective early interventions that reduce the impact of disability and illness persistence.

METHODS

We systematically reviewed the literature for neurobiological parameters (i.e. neuropsychology, neuroimaging, sleep-wake and circadian biology, neurophysiology and metabolic measures) associated with functional domains in young people (12 to 30 years) with mood and/or anxiety disorders.

RESULTS

Of the one hundred and thirty-four studies selected, 7.6 % investigated social and economic participation, 2.1 % physical health, 15.3 % suicide and self-harm behaviours, 6.9 % alcohol and substance use, whereas the majority (68.1 %) focussed on clinical syndrome.

CONCLUSIONS

Despite the predominance of studies that solely examine the clinical syndrome of young people the literature also provides evidence of distinct associations among objective measures (indexing various aspects of brain circuitry) and other functional domains. We suggest that a shift in focus towards characterising the mechanisms that underlie and/or mediate multiple functional domains will optimise personalised interventions and improve illness trajectories.

Diurnal cortisol variation and cortisol response to an MRI stressor in schizophrenia and bipolar disorder

Markers of HPA axis function, including diurnal cortisol rhythm and cortisol responses to stress or pharmacological manipulation, are increasingly reported as disrupted in schizophrenia (SZ) and bipolar disorder (BD). However, there has been no direct comparison of cortisol responses to stress in SZ and BD in the same study, and associations between cortisol dysfunction and illness characteristics remain unclear. In this study we used spline embedded linear mixed models to examine cortisol levels of SZ and BD participants at waking, during the first 45min after waking (representing the cortisol awakening response; CAR), during the period of rapid cortisol decline post the awakening response, and in reaction to a stressor (MRI scan), relative to healthy controls (HC). Contrary to expectations, neither SZ nor BD showed differences in waking cortisol levels, CAR, or immediate post-CAR decline compared to HC; however, waking cortisol levels were greater in BD relative to SZ. In response to the MRI stressor, the SZ group showed a significant absence of the expected increase in cortisol responsivity to stress, which was seen in both the BD and HC groups. Clinical factors affecting the CAR differed between SZ and BD. In SZ, higher antipsychotic medication dosage was associated with a steeper incline of the CAR, while greater positive symptom severity was associated with a more blunted CAR, and greater levels of anxiety were associated with the blunted cortisol response to stress. In BD, longer illness duration was associated with a steeper incline in CAR and lower levels of waking cortisol. These results suggest that cortisol responses may normalize with medication (in SZ) and longer illness duration (in BD), in line with findings of aberrant cortisol levels in the early stages of psychotic disorders.

The HPA axis in bipolar disorder: Systematic review and meta-analysis

OBJECTIVES

To provide a quantitative and qualitative synthesis of the available evidence on the role of Hypothalamic-Pituitary-Adrenal (HPA) axis in the pathophysiology of Bipolar Disorder (BD).

METHODS

Meta-analysis and meta-regression of case-control studies examining the levels of cortisol, ACTH, CRH levels. Systematic review of stress reactivity, genetic, molecular and neuroimaging studies related to HPA axis activity in BD.

RESULTS

Forty-one studies were included in the meta-analyses. BD was associated with significantly increased levels of cortisol (basal and post-dexamethasone) and ACTH, but not of CRH. In the meta-regression, case-control differences in cortisol levels were positively associated with the manic phase (p=0.005) and participants' age (p=0.08), and negatively with antipsychotics use (p=0.001). Reviewed studies suggest that BD is associated with abnormalities of stress-related molecular pathways in several brain areas. Variants of HPA axis-related genes seem not associated with a direct risk of developing BD, but with different clinical presentations. Also, studies on unaffected relatives suggest that HPA axis dysregulation is not an endophenotype of BD, but seems related to environmental risk factors, such as childhood trauma. Progressive HPA axis dysfunction is a putative mechanism that might underlie the clinical and cognitive deterioration of patients with BD.

CONCLUSIONS

BD is associated with dysfunction of HPA axis activity, with important pathophysiological implications. Targeting HPA axis dysfunctions might be a novel strategy to improve the outcomes of BD.

The Neurobiology of Bipolar Disorder: An Integrated Approach

Bipolar disorder is a heterogeneous condition with myriad clinical manifestations and many comorbidities leading to severe disabilities in the biopsychosocial realm. The objective of this review article was to underline recent advances in knowledge regarding the neurobiology of bipolar disorder. A further aim was to draw attention to new therapeutic targets in the treatment of bipolar disorder. To accomplish these goals, an electronic search was undertaken of the PubMed database in August 2015 of literature published during the last 10 years on the pathophysiology of bipolar disorder. A wide-ranging evaluation of the existing work was done with search terms such as "mood disorders and biology," "bipolar disorder and HPA axis," "bipolar disorder and cytokines," "mood disorders and circadian rhythm," "bipolar disorder and oxidative stress," etc. This endeavor showed that bipolar disorder is a diverse condition sharing neurobiological mechanisms with major depressive disorder and psychotic spectrum disorders. There is convincing evidence of crosstalk between different biological systems that act in a deleterious manner causing expression of the disease in genetically predisposed individuals. Inflammatory mediators act in concert with oxidative stress to dysregulate hormonal, metabolic, and circadian homeostasis in precipitating and perpetuating the illness. Stress, whether biologically or psychologically mediated, is responsible for the initiation and progression of the diathesis. Bipolar spectrum disorders have a strong genetic component; severe life stresses acting through various paths cause the illness phenotype.

Chronobiology of bipolar disorder: therapeutic implication

Multiple lines of evidence suggest that psychopathological symptoms of bipolar disorder arise in part from a malfunction of the circadian system, linking the disease with an abnormal internal timing. Alterations in circadian rhythms and sleep are core elements in the disorders, characterizing both mania and depression and having recently been shown during euthymia. Several human genetic studies have implicated specific genes that make up the genesis of circadian rhythms in the manifestation of mood disorders with polymorphisms in molecular clock genes not only showing an association with the disorder but having also been linked to its phenotypic particularities. Many medications used to treat the disorder, such as antidepressant and mood stabilizers, affect the circadian clock. Finally, circadian rhythms and sleep researches have been the starting point of the developing of chronobiological therapies. These interventions are safe, rapid and effective and they should be considered first-line strategies for bipolar depression.

Sleep- and circadian rhythm-associated pathways as therapeutic targets in bipolar disorder

INTRODUCTION

Disruptions in sleep and circadian rhythms are observed in individuals with bipolar disorders (BD), both during acute mood episodes and remission. Such abnormalities may relate to dysfunction of the molecular circadian clock and could offer a target for new drugs.

AREAS COVERED

This review focuses on clinical, actigraphic, biochemical and genetic biomarkers of BDs, as well as animal and cellular models, and highlights that sleep and circadian rhythm disturbances are closely linked to the susceptibility to BDs and vulnerability to mood relapses. As lithium is likely to act as a synchronizer and stabilizer of circadian rhythms, we will review pharmacogenetic studies testing circadian gene polymorphisms and prophylactic response to lithium. Interventions such as sleep deprivation, light therapy and psychological therapies may also target sleep and circadian disruptions in BDs efficiently for treatment and prevention of bipolar depression.

EXPERT OPINION

We suggest that future research should clarify the associations between sleep and circadian rhythm disturbances and alterations of the molecular clock in order to identify critical targets within the circadian pathway. The investigation of such targets using human cellular models or animal models combined with 'omics' approaches are crucial steps for new drug development.

Hypothalamic-pituitary-adrenocortical axis: neuropsychiatric aspects

Evidence of aberrant hypothalamic-pituitary-adrenocortical (HPA) activity in many psychiatric disorders, although not universal, has sparked long-standing interest in HPA hormones as biomarkers of disease or treatment response. HPA activity may be chronically elevated in melancholic depression, panic disorder, obsessive-compulsive disorder, and schizophrenia. The HPA axis may be more reactive to stress in social anxiety disorder and autism spectrum disorders. In contrast, HPA activity is more likely to be low in PTSD and atypical depression. Antidepressants are widely considered to inhibit HPA activity, although inhibition is not unanimously reported in the literature. There is evidence, also uneven, that the mood stabilizers lithium and carbamazepine have the potential to augment HPA measures, while benzodiazepines, atypical antipsychotics, and to some extent, typical antipsychotics have the potential to inhibit HPA activity. Currently, the most reliable use of HPA measures in most disorders is to predict the likelihood of relapse, although changes in HPA activity have also been proposed to play a role in the clinical benefits of psychiatric treatments. Greater attention to patient heterogeneity and more consistent approaches to assessing treatment effects on HPA function may solidify the value of HPA measures in predicting treatment response or developing novel strategies to manage psychiatric disease.

Advancing biomarker research: utilizing 'Big Data' approaches for the characterization and prevention of bipolar disorder

OBJECTIVE

To provide a strategic framework for the prevention of bipolar disorder (BD) that incorporates a 'Big Data' approach to risk assessment for BD.

METHODS

Computerized databases (e.g., Pubmed, PsychInfo, and MedlinePlus) were used to access English-language articles published between 1966 and 2012 with the search terms bipolar disorder, prodrome, 'Big Data', and biomarkers cross-referenced with genomics/genetics, transcriptomics, proteomics, metabolomics, inflammation, oxidative stress, neurotrophic factors, cytokines, cognition, neurocognition, and neuroimaging. Papers were selected from the initial search if the primary outcome(s) of interest was (were) categorized in any of the following domains: (i) 'omics' (e.g., genomics), (ii) molecular, (iii) neuroimaging, and (iv) neurocognitive.

RESULTS

The current strategic approach to identifying individuals at risk for BD, with an emphasis on phenotypic information and family history, has insufficient predictive validity and is clinically inadequate. The heterogeneous clinical presentation of BD, as well as its pathoetiological complexity, suggests that it is unlikely that a single biomarker (or an exclusive biomarker approach) will sufficiently augment currently inadequate phenotypic-centric prediction models. We propose a 'Big Data'- bioinformatics approach that integrates vast and complex phenotypic, anamnestic, behavioral, family, and personal 'omics' profiling. Bioinformatic processing approaches, utilizing cloud- and grid-enabled computing, are now capable of analyzing data on the order of tera-, peta-, and exabytes, providing hitherto unheard of opportunities to fundamentally revolutionize how psychiatric disorders are predicted, prevented, and treated. High-throughput networks dedicated to research on, and the treatment of, BD, integrating both adult and younger populations, will be essential to sufficiently enroll adequate samples of individuals across the neurodevelopmental trajectory in studies to enable the characterization and prevention of this heterogeneous disorder.

CONCLUSIONS

Advances in bioinformatics using a 'Big Data' approach provide an opportunity for novel insights regarding the pathoetiology of BD. The coordinated integration of research centers, inclusive of mixed-age populations, is a promising strategic direction for advancing this line of neuropsychiatric research.

The Interface of Stress and the HPA Axis in Behavioural Phenotypes of Mental Illness

Abnormalities of hypothalamic-pituitary-adrenal (HPA) axis function are one of the most consistent biological findings across several mental disorders, but many of the mechanisms underlying this abnormality as well as the potential contribution to behavioural phenotypes remain only partially understood. Interestingly, evidence suggests a U-curve, with dysregulation of the HPA axis towards both hyper- or hypoactivity manifesting as a risk to mental wellbeing. This review will elaborate on both the clinical and molecular role of the neuroendocrine stress system in depressive, psychotic and post-traumatic stress disorders and present some of the most recent findings that have shed light on the complex interface between environmental stressors, molecular mechanisms and clinical presentation. Crucially, plasticity of the HPA axis confers both vulnerability to adverse events, particularly so in early developmental stages, as well as hope for the treatment of mental disorder, as evidenced by changes in HPA functioning associated with remission of symptoms.

Depressed suicidal adolescent males have an altered cortisol response to a pharmacological challenge

Dysregulation of the HPA axis and the dysfunction of the central serotonin (5HT) system are the most replicated biomarkers of depression and suicidal ideation and behavior. However, few studies have examined the two systems simultaneously. In this study, cortisol response was measured in depressed adolescents, following the administration of a central serotonin receptor agonist, meta-chlorphenylpiprazine (mCPP). Adolescents with major depression (MDD; n = 44; males = 15, females = 29; mean age ± SD = 15.5 ± 1.5) were divided into two groups: non-suicidal or those who reported passive suicidal ideation (n = 21), and those who had either threatened suicide or engaged in suicidal acts (n = 23). Sequential infusions of normal saline and mCPP were administered, and serial blood samples were collected for cortisol response. A differential time by group pattern of cortisol response following mCPP was found in the entire group (F(6,242) = 2.6, p=0.018). However, this was mostly attributed to males (F(6,73) = 2.3, p = 0.043) who had threatened or engaged in suicidal acts and displayed a higher cortisol response at 10 and 25 min after the infusion of mCPP, which was not affected by the severity of depression. This differential pattern of cortisol secretion in response to a serotonergic agonist may be a biomarker for more severe forms of suicidal ideation and behavior in adolescent males.

Mood and metabolic consequences of sleep deprivation as a potential endophenotype' in bipolar disorder

It has been commonly recognized that circadian rhythm and sleep/wake cycle are causally involved in bipolar disorder. There has been a paucity of systematic research considering the relations between sleep and mood states in bipolar disorder. The current study examines the possible influences of sleep deprivation on mood states and endocrine functions among first-degree relatives of patients with bipolar disorder and healthy controls. Blood samples were taken at two time points in the consecutive mornings at predeprivation and postdeprivation periods. Participants simultaneously completed the Profiles of Mood States at two time points after giving blood samples. Plasma T3 and TSH levels increased after total sleep deprivation in both groups. Sleep deprivation induced TSH levels were reversely associated with depression-dejection among healthy controls. A paradoxical effect was detected for only the first-degree relatives of the patients that changes in plasma cortisol levels negatively linked to depression-dejection and anger-hostility scores after total sleep deprivation. Plasma DHEA levels became correlated with vigor-activity scores after sleep deprivation among first-degree relatives of bipolar patients. On the contrary, significant associations of depression-dejection, anger-hostility, and confusion-bewilderment with the baseline plasma DHEA levels became statistically trivial in the postdeprivation period. Findings suggested that first-degree relatives of patients with bipolar disorder had completely distinct characteristics with respect to sleep deprivation induced responses in terms of associations between endocrine functions and mood states as compared to individuals whose relatives had no psychiatric problems. Considering the relationships between endocrine functions and mood states among relatives of the patients, it appears like sleep deprivation changes the receptor sensitivity which probably plays a pivotal role on mood outcomes among the first-degree relatives of patients with bipolar disorder.

Salivary cortisol and interpersonal functioning: an event-contingent recording study in the offspring of parents with bipolar disorder

Despite a large body of research in non-human primates, the relationship between naturalistic patterns of social behaviour and basal cortisol levels has been understudied in humans. The present study examined the relationship between patterns of interpersonal functioning and cortisol levels in 23 offspring of parents with bipolar disorder (BD), at high risk for the development of an affective disorder, and 22 offspring of parents with no affective disorder (controls) in late adolescence and young adulthood. Using event-contingent recording, participants rated their dominance, submissiveness, quarrelsomeness, and agreeableness in naturally occurring social interactions over 14 consecutive days and provided salivary cortisol twice daily in the afternoon over the same period. In the full sample, multilevel modelling analyses revealed that dominance was a significant positive predictor of afternoon basal cortisol levels, t(35)=2.58, p<0.05. Moreover, risk group (having a parent with BD or parents with no affective disorder) significantly interacted with mean levels of quarrelsomeness to predict afternoon cortisol levels, t(29)=2.06, p<0.05. Offspring of parents with BD who reported more frequent quarrelsome behaviours exhibited lower levels of afternoon cortisol relative to high-risk offspring reporting few quarrelsome behaviours and control offspring. The results are consistent with evidence that dominance is associated with high cortisol levels in an unstable environment, and suggest that quarrelsomeness among high risk youth contributes to altered hypothalamic-pituitary-adrenal activity.

Long-term cortisol in bipolar disorder: associations with age of onset and psychiatric co-morbidity

INTRODUCTION

Dysregulation of the hypothalamic-pituitary-adrenal (HPA) axis is hypothesized to play a role in the pathogenesis of bipolar disorder (BD). Conflicting results have been reported when saliva or serum was used to measure cortisol levels. A recently developed method is to measure cortisol in scalp hair, with 1cm of scalp hair representing 1 month. We studied whether there are differences in long-term hair cortisol levels between BD patients and healthy individuals and whether there are associations between hair cortisol and disease characteristics.

METHODS

Hair samples were collected in 100 BD patients and 195 healthy controls. Long-term cortisol levels were determined in 3 cm hair segments. Saliva samples were collected on two consecutive evenings. Documented disease characteristics were disease state, age of onset and psychiatric co-morbidity.

RESULTS

Hair cortisol levels were not statistically different in BD patients compared to healthy controls (p=0.233) and were not associated with the disease state at the moment of sample collection (p=0.978). In the subgroup of patients with age of onset ≥ 30 years, hair cortisol levels were significantly elevated compared to the subgroup with age of onset <30 years and to healthy controls (p=0.004). Psychiatric co-morbidity was associated with elevated cortisol levels (44.87 versus 31.41 pg/mg hair; p=0.021), with the exclusion of panic disorder, which was associated with decreased cortisol levels (22.13 versus 34.67 pg/mg hair; p=0.019).

CONCLUSIONS

Elevated long-term cortisol levels might play a role in a subgroup of patients with BD. There may be differences in pathogenesis of younger and older onset BD suggesting two different disease entities.

Personality of parents with bipolar disorder and interpersonal functioning among their offspring: a prospective 10-year study

A comparison of offspring of parents with bipolar disorder (OBD) and offspring of parents with no mental disorder (ONMD) showed that parents' neuroticism was associated with internalizing and externalizing problems among their children. The present study examined whether parents' neuroticism predicted poor interpersonal functioning among offspring 10 years later and whether the problems observed in middle childhood mediated the association between parents' neuroticism and offspring functioning. When offspring were in middle childhood, parents completed the revised NEO Personality Inventory and rated the child's behavior on the Child Behavior Checklist. Ten years later, 65 OBD and 59 ONMD completed interviews assessing mental disorders and interpersonal and noninterpersonal functioning. High neuroticism and low agreeableness in parents predicted poor interpersonal functioning in their offspring in late adolescence-early adulthood. The offspring's externalizing and internalizing problems in middle childhood partially mediated the association between parents' personality and offspring interpersonal functioning. Moreover, the association between parents' neuroticism and offspring internalizing problems was stronger among the OBD than the ONMD. Overall, the results suggested an intergenerational transmission of risk whereby high neuroticism and low agreeableness in parents were associated with behavioral problems among offspring in middle childhood that, in turn, predicted poor interpersonal functioning 10 years later.

Biological indicators of illness risk in offspring of bipolar parents: targeting the hypothalamic-pituitary-adrenal axis and immune system

AIM

The study aims to provide a selective review of the literature pertaining to the hypothalamic-pituitary-adrenal (HPA) axis and immune abnormalities as informative biological indicators of vulnerability in bipolar disorder (BD).

METHOD

We summarize key findings relating to HPA axis and immunological abnormalities in bipolar patients and their high-risk offspring. Findings derive from a review of selected original papers published in the literature, and supplemented by papers identified through bibliography review. Neurobiological findings are discussed in the context of emergent BD in those at genetic risk and synthesized into a neurodevelopmental model of illness onset and progression.

RESULTS

BD is associated with a number of genetic and possibly epigenetic abnormalities associated with neurotransmitter, hormonal and immunologically mediated neurobiological pathways. Data from clinical and high-risk studies implicate HPA axis and immune system abnormalities, which may represent inherited vulnerabilities important for the transition to illness onset. Post-mortem and clinical studies implicate intracellular signal transduction processes and disturbance in energy metabolism associated with established BD. Specifically, long-standing maladaptive alterations such as changes in neuronal systems may be mediated through changes in intracellular signalling pathways, oxidative stress, cellular energy metabolism and apoptosis associated with substantial burden of illness.

CONCLUSIONS

Prospective longitudinal studies of endophenotypes and biomarkers such as HPA axis and immune abnormalities in high-risk offspring will be helpful to understand genetically mediated biological pathways associated with illness onset and progression. A clinical staging model describing emergent illness in those at genetic risk should facilitate this line of investigation.

Glucocorticoid sensitivity in mood disorders

In this review, we provide an overview of recent literature on glucocorticoid (GC) sensitivity in mood disorders. Assessing GC sensitivity is often performed by measuring the cortisol awakening rise (CAR), by challenging the hypothalamic-pituitary-adrenal (HPA) axis using a dexamethasone suppression test (DST) or a dexamethasone/cortisol-releasing hormone test (DEX/CRH); more recently by measuring cortisol as a retrospective calendar in scalp hair. The main findings in mood disorders are higher mean cortisol levels in hair samples and a higher CAR, showing a hyperactivity of the HPA axis. This is in line with the mild resistance for GCs previously observed in challenge tests during mood episodes. GC sensitivity is partly determined by polymorphisms in the genes encoding receptors and other proteins involved in the regulation of the HPA axis. We shortly discuss the glucocorticoid receptor, as well as the mineralocorticoid receptor, the cortisol-releasing hormone receptor-1, and the glucocorticoid receptor co-chaperone FKBP5. Data clearly indicate genetic changes, along with epigenetic changes which influence the set-point and regulation of the HPA axis. Early trauma, as well as influences in utero, appears to be important. Future research is necessary to further clarify the biological background and consequences of an individual's cortisol exposure in relation to mood.

Glucocorticoid and mineralocorticoid receptor polymorphisms and clinical characteristics in bipolar disorder patients

INTRODUCTION

The hypothalamus-pituitary-adrenal (HPA)-axis is often found to be dysregulated in bipolar disorder (BD) while stress and changes in day-night rhythms can trigger a new mood episode. Genetic variants of the glucocorticoid receptor (GR)- and mineralocorticoid receptor (MR)-gene influence both the reactivity of the stress-response and associate with changes in mood. In this study we tested the hypothesis that these polymorphisms associate with different clinical characteristics of BD.

METHODS

We studied 326 outpatients with BD and performed GR genotyping of the TthIIII, ER22/23EK, N363S, BclI, and 9β polymorphisms, as well as MR genotyping of the 2G/C and I180V variants. All patients were interviewed for clinical characteristics.

RESULTS

Seasonal patterns of hypomania are related to the BclI haplotype and the TthIIII+9β haplotype of the GR gene (respectively, crude p=.007 and crude p=.005). Carriers of the ER22/23EK polymorphism had an almost 8 years earlier onset of their first (hypo)manic episode than non-carriers (crude p=.004, after adjustment p=.016). No evidence for a role of the MR in modifying clinical manifestations was found.

CONCLUSION

Polymorphisms of the GR-gene are factors which influence some clinical manifestations of BD, with respect to seasonal pattern of (hypo)mania and age of onset.

Sensitivity to stress among the offspring of parents with bipolar disorder: a study of daytime cortisol levels

BACKGROUND

It is well known that the hypothalamic-pituitary-adrenal (HPA) axis is compromised in major depression and bipolar disorder. There is increasing evidence that subtle HPA abnormalities, such as elevated cortisol levels, precede the development of an affective disorder. Interpersonal stress is also associated with the development of affective disorders. The present study sought to determine whether interpersonal chronic and episodic stress moderated the relationship between cortisol levels in the natural environment and risk status, defined as having a parent with bipolar disorder.

METHOD

Sixty-two offspring of parents with bipolar disorder (OBD) and 60 offspring with no family history of affective disorders (OFH-), aged 19.48 years (s.d.=3.38, range 14-28), completed interviews assessing mental disorders and chronic and episodic stress, and provided saliva samples over 3 days.

RESULTS

Regression analyses revealed that the OBD who experienced high interpersonal chronic stress displayed a larger cortisol rise following awakening than the OBD reporting low interpersonal chronic stress. The same relationship was also found for levels of non-interpersonal chronic stress. The OBD who reported experiencing severe interpersonal episodic stress exhibited higher levels of daytime cortisol than the OBD reporting interpersonal episodic stress of mild severity. Importantly, none of the above relationships were detected in the OFH-. Each of the interactions between family history of affective disorders and stress remained after controlling for age, gender and offspring lifetime affective disorders and current non-affective disorders.

CONCLUSIONS

A biological sensitivity to stress may underlie the susceptibility to affective disorders among the OBD.

Circadian biomarkers, circadian genes and bipolar disorders

Bipolar disorders are associated with circadian deregulations both during acute mood episodes and during euthymic periods, suggesting that these circadian rhythms may represent trait markers of the disease. Several arguments demonstrate that deregulations of circadian rhythms may be part of the pathophysiology of bipolar disorders. Abnormal quantitative and qualitative circadian disturbances have been repeatedly showed in bipolar patients, both during euthymic periods and acute phases, using different assessment tools such as actigraphy, polysomnography, and blood melatonin monitoring. In addition, many circadian physiological functions have been demonstrated to be altered in bipolar patients, such as secretion of hormones and other endogenous substances, core temperature, and fibroblasts activity. Furthermore, mood stabilizers efficiency could partially be explained by their impact on the regulation of the circadian rhythms. The implication of genetic vulnerability factors has long been demonstrated in bipolar disorders and several circadian genes have been tested for association in bipolar disorders. Although preliminary, interesting results have been obtained in several independent studies.

Elevated daytime cortisol levels: a biomarker of subsequent major affective disorder?

BACKGROUND

Several studies have reported that the offspring of parents with affective disorders secrete high levels of daytime cortisol. A few studies have shown that high cortisol levels preceded the onset of affective symptoms. Only one study to date has found that an elevation in cortisol preceded the onset of an affective disorder, but this was observed only in those youth carrying the short allele of the serotonin transporter gene promoter polymorphism (Goodyer et al., 2009).

METHODS

We followed 28 offspring of parents with bipolar disorder and 31 offspring of parents with no affective disorder from an average age of 17.5years to an average age of 20.0years to determine if cortisol levels at baseline predicted the subsequent development of an affective disorder. At baseline and at follow-up participants completed a diagnostic assessment, and at baseline they provided saliva samples. Daytime cortisol levels were computed as the mean of eight to 24 samples measured across two to six days.

RESULTS

Among the 59 participants, cortisol levels at the mean age of 17.5years predicted the development of an affective disorder during the subsequent 2.5year (odds ratio: 2.1, 95% confidence interval=1.0-4.1, p<0.05) after controlling for offspring mental disorders at the first assessment and having a parent with bipolar disorder.

LIMITATIONS

The findings should be interpreted with caution, as the sample size was small.

CONCLUSION

Elevated daytime cortisol levels in late adolescence may be a biomarker of vulnerability for affective disorders.

From predisposition to illness: genetically sensitive intermediate pathways to mood disorders

The contemporary model of mood disorders proposes that multiple susceptibility genes interact with multiple other risk factors. However, the specific nature of the genetic vulnerability and the intermediate causal pathways are not known. In this edition of the Journal, Goodyer and colleagues report new findings suggesting genetic moderation of an association between elevated cortisol and depression in high-risk adolescents.

Automatic emotional information processing and the cortisol response to acute psychosocial stress

Attentional shifting may represent a means of regulating the stress response. Previously, automatic processing of emotional information was predictive of subsequent cortisol levels during a repeated loss stressor (Ellenbogen, Schwartzman, Stewart, & Walker, 2006). The stress induction did not, however, elicit a substantive cortisol increase. Thus, we sought to replicate this finding using the Trier Social Stress Test (TSST), a validated psychosocial stress induction. Seventy-nine students performed a modified spatial cuing task with supraliminal and masked pictorial stimuli during the TSST (n = 36) and a control condition (n = 43). The TSST elicited a greater cortisol response than did the control condition [F(1,76) = 4.6, p < .05]. Attentional shifting during trials with masked angry faces predicted cortisol change during the TSST (beta = .76; t = 2.1, p < .05), but not during the control condition. These data suggest that early automatic emotional information processing is important in the regulation of the cortisol stress response, although the direction of effect is not known.