Patterns of salivary cortisol secretion and responses to daily events in patients with remitted bipolar disorder

Sleep and circadian disruption in bipolar disorders: From psychopathology to digital phenotyping in clinical practice

Sleep and biological rhythms are integral to mood regulation across the lifespan, particularly in bipolar disorder (BD), where alterations in sleep phase, structure, and duration occur in all mood states. These disruptions are linked to poorer quality of life, heightened suicide risk, impaired cognitive function, and increased relapse rates. This review highlights the pathophysiology of sleep disturbances in BD and aims to consolidate understanding and clinical applications of these phenomena. It also summarizes the evolution of sleep and biological rhythms assessment methods, including ecological momentary assessment (EMA) and digital phenotyping. It underscores the importance of recognizing circadian rhythm involvement in mood regulation, suggesting potential therapeutic targets. Future research directions include elucidating circadian clock gene mechanisms, understanding environmental impacts on circadian rhythms, and investigating the bidirectional relationship between sleep disturbances and mood regulation in BD. Standardizing assessment methods and addressing privacy concerns related to EMA technology and digital phenotyping are essential for advancing research. Collaborative efforts are crucial for enhancing clinical applicability and understanding the broader implications of biological rhythms in BD diagnosis and treatment. Overall, recognizing the significance of sleep and biological rhythms in BD offers promise for improved outcomes through targeted interventions and a deeper understanding of the disorder's underlying mechanisms.

The influence of chronic inflammation on the illnesscourse of bipolar disorder: A longitudinal study

INTRODUCTION

C-reactive protein (CRP) is a systemic inflammatory marker, which indicates systemic inflammatory processes It is involved in different inflammatory processes of the body and is a reliable marker for the general inflammatory state of the body. High sensitive CRP seems to play a key role as a state and trait marker of bipolar disorder (BD). In the current study, we tried to determine the long-term effect of CRP levels on clinical symptoms and illness course of bipolar disorder.

METHODS

For the current study, we examined 106 patients with BD for a period of four years. Participants underwent a clinical screening for depressive and manic episodes with the Hamilton Depression Scale (HAMD) and the Young Mania Rating Score (YMRS) and a serological diagnostic for inflammatory parameters every six months, thus leading to 8 measurement times in total. Patients with the presence of severe medical or neurological comorbidities such as active cancer, chronic obstructive lung disease, rheumatoid arthritis, systemic lupus erythematosus, Alzheimer's disease, Parkinson's disease, Huntington's disease or multiple sclerosis and acute infections were not included in the study.

RESULTS

In our sample, 26% showed a mean hsCRP above 5 mg/dl. Those patients showed a significantly higher mean YMRS score than those with a mean hsCRP under 5 mg/dl during our observation period. Regarding HAMD there was no significant difference in hsCRP values. The existence of lithium treatment showed no significant influence on mean hsCRP levels between the start and endpoint.

CONCLUSION

Individuals who were exposed to a higher level of inflammation over time suffered from more manic symptoms in this period. These findings underline the hypothesis that inflammatory processes have an accumulative influence on the illness course of BD, especially concerning manic symptoms and episodes.

Differential Diagnosis of Major Depressive Disorder and Bipolar Disorder: Genetic and Hormonal Assessment and the Influence of Early-Life Stress

Few studies have assessed biomarkers for the differentiation of major depressive disorder (MDD) and bipolar disorder (BD). However, some elements of depression such as hormones and receptors of the renin-angiotensin-adrenal system (RAAS), the hypothalamus-pituitary-adrenal (HPA) axis, and history of early-life stress (ELS) could be considered for differential diagnosis. Therefore, this study aimed to assess aldosterone and cortisol levels, MR and GR gene polymorphisms, and ELS as potential biomarkers for differentiating MDD and BD. This study presents a case-control design. Groups comprised samples for genetic, cortisol, and aldosterone analysis: healthy control (HC; n = 113/97/103), MDD (n = 78/69/67) and BD (n = 82/68/65) subjects. Furthermore, all subjects were assessed for diagnostic screening, the severity of depression, and history of ELS by applying MINI-PLUS, GRID-HDRS, and CTQ, respectively. In addition, genotype and allelic frequencies of GR (N363S, R22/23K and BclI) and MR (MI180V and -2G/C) polymorphisms were evaluated via PCR. Our findings demonstrate that basal aldosterone levels may be a biomarker for differentiating BD and MDD. Furthermore, ELS affects the HPA axis in BD, cortisol may be considered a biomarker for distinguishing BD and MDD, but only in the absence of ELS, and, finally, history of ELS and MR-2G/C variant alleles are factors that contribute to the severity of depressive symptoms in MDD and BD.

Physiological reactions to acute stressors and subjective stress during daily life: A systematic review on ecological momentary assessment (EMA) studies

OBJECTIVE

This review aims to provide an overview of ecological momentary assessment (EMA) studies analyzing stress reactivity during daily life in terms of direct and moderated influence of acute stress on physiological responses.

MATERIALS AND METHODS

A systematic literature search was performed on November 29, 2021 using Web of Science, MEDLINE and PsycINFO to identify prospective EMA studies targeting acute stressors or stress under naturalistic conditions, without restrictions of publication date or population. Study quality was assessed for multiple EMA-specific sources of bias.

RESULTS

Out of 4285 non-duplicate records, 107 publications involving 104 unique studies were included. The majority of studies assessed acute physiological stress responses primarily through salivary cortisol (n = 59) and cardiovascular outcomes (n = 32). Most studies performed at least three measurements per day (n = 59), and had a moderate risk of recall bias (n = 68) and confounding (n = 85). Fifty-four studies reported a compliance of ≥80%. Direct, non-moderated positive associations were observed between acute stress exposure and concurrent cortisol levels (44%, n = 11/25), systolic (44%, 8/18) and diastolic blood pressure (53%, 8/15) and heart rate (53%, 9/17). Several inter- and intra-individual moderators were identified, such as age, gender, health status, chronic stress, work-related resources, physical activity and stress coping indicators.

CONCLUSIONS

About half of the reviewed EMA studies demonstrated direct associations between everyday acute stress exposure and physiological responses, including increased cortisol levels, blood pressure and heart rate. Results further suggested various moderator variables that could help develop tailored prevention strategies and identify groups at higher risk for dysfunctional stress responses.

REGISTRATION

PROSPERO-Reg.-No.: PROSPERO 2020 CRD42020163178.

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.

Sleep disturbances in the context of neurohormonal dysregulation in patients with bipolar disorder

Background

Sleep dysfunction is a core symptom in bipolar disorder (BD), especially during major mood episodes. This study investigated the possible link between subjective and objective sleep disturbances in inter-episode BD, changes in melatonin and cortisol levels, and circadian melatonin alignment. The study included 21 euthymic BD patients and 24 healthy controls. Participants had to wear an actigraphy device, keep a weekly sleep diary and take salivary samples: five samples on the last evening to determine the dim light melatonin onset (DLMO) and one the following morning to measure rising cortisol. Sleep quality was assessed by the Pittsburgh Sleep Quality Index (PSQI) and Regensburg Insomnia Scale (RIS), and circadian alignment by the phase angle difference (PAD).

Results

In comparison to healthy controls, BD patients had: (1) higher PSQI (5.52 ± 3.14 vs. 3.63 ± 2.18; p = 0.022) (significant after controlling for age and gender), and higher RIS scores (8.91 ± 5.43 vs. 5.83 ± 3.76; p = 0.031); (2) subjective a longer mean TST (p = 0.024) and TIB (p = 0.002) (both significant after controlling for age and gender), longer WASO (p = 0.019), and worse SE (p = 0.036) (significant after controlling for gender); (3) actigraphically validated earlier sleep onset (p = 0.002), less variation in sleep onset time (p = 0.005) and no longer TST (p = 0.176); (4) no differing melatonin levels (4.06 ± 2.77 vs. 3.35 ± 2.23 p = 0.352), an 1.65 h earlier DLMO (20.17 ± 1.63 vs. 21.82 ± 1.50; p = 0. 001) (significant after controlling for gender), and a phase advance of melatonin (6.35 ± 1.40 vs. 7.48 ± 1.53; p = 0.017) (significant after controlling for gender); and (5) no differing cortisol awakening response (16.97 ± 10.22 vs 17.06 ± 5.37 p = 0.969).

Conclusions

Patients with BD, even in euthymic phase, have a significantly worse perception of their sleep. Advanced sleep phases in BD might be worth further investigation and could help to explain the therapeutic effects of mood stabilizers such as lithium and valproate.

Variability in Sleep Is Associated with Trait-Based and Daily Measures of Bipolar Spectrum Psychopathology

INTRODUCTION

Although sleep disturbances are well documented in bipolar spectrum disorders (BSDs), significantly less research has examined whether these disturbances are present in those at risk for developing BSDs or with subsyndromal symptoms. The present study examined associations between risk for BSDs, as measured by the Hypomanic Personality Scale (HPS), and sleep assessed using experience sampling. We assessed whether intraindividual variability in sleep was associated with affect, cognition, and behavior in daily life and potential directionality of these relationships.

METHODS

233 young adults oversampled for high scores on the HPS completed 14 days of experience sampling assessing total sleep time (TST), bed/rise time, sleep quality, affect (negative and positive affect), cognition (difficulty concentrating, racing thoughts), and behavior (impulsivity) in daily life. We used Dynamic Structural Equation Modeling (DSEM) to assess within-person links between sleep and bipolar spectrum psychopathology.

RESULTS

HPS scores were associated with less TST, later bedtime, and more variable TST and bedtime. Variability in TST was associated with negative affect, difficulty concentrating/racing thoughts, and impulsivity. Within-person decreases in sleep were associated with next day increases in negative affect, stress, difficulty concentrating, and racing thoughts.

LIMITATIONS

Measurement of sleep was limited. Future studies should examine both objective measures of sleep (e.g., actigraphy) and fragmentation in sleep.

CONCLUSIONS

Risk for BSD was associated with similar patterns of sleep disruptions as seen in BSDs. Important dynamic links between sleep and bipolar spectrum psychopathology emerged indicating that sleep is an important target for improving symptoms of BSDs in daily life.

Dopamine release during psychological stress in euthymic bipolar I disorder: a Positron Emission Tomography study with [11C]raclopride

BACKGROUND

Neurochemical mechanisms underlying stress induced relapse of mood episodes in Bipolar I Disorder (BD) remain unknown. This study investigated whether euthymic BD patients have a greater dopamine release in ventral striatum, caudate and putamen in response to psychological stress using Positron Emission Tomography (PET) scanning with the radiotracer [¹¹C]raclopride.

METHODS

Euthymic patients with BD (n = 10) and 10 matched healthy controls underwent two [¹¹C]raclopride PET scans, one during a "stress" and the other in a "no stress" condition separated by at least 24 h. Montreal Imaging Stress Test (MIST) was used to induce stress during stress condition. Participants received an injection of [¹¹C]raclopride over one minute followed by PET scan for 60 min. Participants were assessed for mood symptom severity at baseline, and before and after each scan. The reduction in [¹¹C]raclopride binding in stress condition compared with non-stress rest condition for each subject provided an estimate of dopamine release due to stress.

RESULTS

There was a significant effect of stress in reducing the [¹¹C]raclopride binding in the ventral striatum, caudate and putamen; however, no significant effects of group or condition x group interaction were found.

LIMITATIONS

Small sample size and recruitment of euthymic patients who may be less vulnerable to stress may limit the generalizability of findings.

CONCLUSIONS

Our findings showed that psychological stress led to dopamine release in the basal ganglia for all participants but the magnitude of dopamine release during a stress task was not different between euthymic BD patients and healthy controls.

Hair cortisol, social support, personality traits, and clinical course: differences in schizophrenia and bipolar disorder

OBJECTIVE

This study aimed to investigate the differences in the relationship between hair cortisol concentration (HCC) and psychosocial stress, social support, clinical features, clinical course, and outcome in schizophrenia and bipolar disorder.

METHODS

A total of 109 schizophrenia patients, 93 bipolar disorder patients and 86 healthy controls between 18 and 60 years old were enrolled in the study. Linear regression and factor analysis were employed to examine and compare the relationship between HCC and childhood trauma, the number of stressful life events, the amount of social support in the three months before the hair cortisol assessment, clinical fearures, clinical course, and outcome in schizophrenia and bipolar disorder.

RESULTS

HCC is significantly associated with clinical syndromes, including depression-anxiety factor of Positive and Negative Syndrome Scale in schizophrenia patients, and thought disorder in bipolar disorder patients. However, HCC is positively related to social support and personality traits only in schizophrenia patients but not in bipolar disorder patients. Factor analysis indicates schizophrenia and bipolar disorder share a very similar but somewhat different structure in terms of HCC, psychosocial stress, social support, clinical features, clinical course, and outcome.

CONCLUSION

Findings support that schizophrenia and bipolar disoder have a significant overlap in both clinical characteristics and enviromental risk factors. Aberrant HCC contributes to the complexity of clinical characteristics mainly in schizophrenia.

A panel of rhythm gene polymorphisms is involved in susceptibility to type 2 diabetes mellitus and bipolar disorder

Background

Biological rhythm is closely related to health. We aimed to identify the potential correlations of rhythm gene polymorphisms to type 2 diabetes mellitus (DM) or bipolar disorder (BD), which both have many abnormal rhythmic activities, in a sample of Chinese Han origin.

Methods

A total of 136 patients with BD, 166 patients with DM, and 130 healthy controls were collected. We screened 28 single nucleotide polymorphisms (SNPs) located in rhythm genes CLOCK, ARNTL, PER2, PER3, CRY1, and CRY2 respectively. Snapshot typing technology was used for genotyping.

Results

Both the rs10832022-G and rs11022765-A allele frequencies of the ARNTL gene were significantly higher in patients with DM than in those with BD (corrected P=0.03, 0.004, respectively). The frequency of rs10832022-G, rs1022765-A, and rs11022762-T haplotypes, which was significantly lower in patients with BD than in controls (P=0.003, OR =0.579), was significantly higher in patients with DM than in those with BD (P=0.0002, OR =1.878). The rs2292910-CC genotypic frequency of the CRY2 gene was significantly higher in patients with BD than in controls (OR of regression =2.203, P=0.01), while the frequency of the AA genotype was significantly lower than in patients with DM (P=0.01). The frequency of rs1972874-G and rs36124720-G haplotype of the PER2 gene was significantly higher in patients with DM than in controls (P=0.01, OR =1.577).

Conclusions

Our study preliminarily suggested that both BD and type 2 DM could be considered as dysrhythmias with different rhythmic genetic backgrounds, which contribute to the early prediction of an individual’s susceptibility to different rhythm disorders and early intervention.

Combined cortisol and melatonin measurements with detailed parameter analysis can assess the circadian rhythms in bipolar disorder patients

OBJECTIVES

Bipolar disorder (BD) is a common chronic mental illness. The circadian clock disorder shows a significant correlation with the pathogenesis, phenotype and recurrence of BD. We aim to evaluate non-invasive methods that can comprehensively assess the circadian rhythmicity in BD patients.

METHODS

We non-invasively collected salivary samples and oral epithelial cells from recruited subjects. Then the levels of cortisol and melatonin in saliva were measured and the circadian clock gene expressions (PER2 and BMAL1) of epithelial cells were analyzed. Due to the disease characteristics of the manic patients who were difficult to cooperate with the protocol, only one patient at manic episode was recruited. Besides, 11 patients at the depressive episode, 15 healthy controls and four patients at recovery stage were recruited.

RESULTS

Our results exhibited that the peak phase of cortisol level mainly manifested around 8:00 a.m., and the maximal melatonin level reached around 5:00 a.m. The phase of cortisol in patients with depression did not change significantly, but the level of cortisol decreased significantly, while the phase of melatonin level moved forward about 2.5 hr. Furthermore, the levels and phases of cortisol and melatonin in recovery patients tended to be similar to those of healthy controls.

CONCLUSIONS

With detailed parameter analysis, the combined detection of melatonin and cortisol can better judge the biological clock disorder of bipolar patients. The circadian rhythms of patients at the recovery stage tend to be normal. The clock gene expression examination needs strict quality control and more investigations before being applied to assess human circadian rhythms.

Associations between the cortisol awakening response and patient-evaluated stress and mood instability in patients with bipolar disorder: an exploratory study

OBJECTIVE

The Cortisol Awakening Response (CAR) measured as the transient increase in cortisol levels following morning awakening appears to be a distinct feature of the HPA axis. Patients with bipolar disorder (BD) experience daily stress, mood instability (MI) and studies have shown disrupted HPA-axis dynamics.

AIMS

to evaluate (1) patient-evaluated stress against the CAR, (2) associations between the CAR and mood symptoms, and (3) the effect of smartphone-based treatment on the CAR.

METHODS

Patients with BD (n = 67) were randomized to the use of daily smartphone-based monitoring (the intervention group) or to the control group for six months. Clinically rated symptoms according to the Hamilton Depression Rating Scale 17-items (HDRS), the Young Mania Rating Scale (YMRS), patient-evaluated perceived stress using Cohen's Perceived Stress Scale (PSS) and salivary awakening cortisol samples used for measuring the CAR were collected at baseline, after three and six months. In the intervention group, smartphone-based data on stress and MI were rated daily during the entire study period.

RESULTS

Smartphone-based patient-evaluated stress (B: 134.14, 95% CI: 1.35; 266.92, p = 0.048) and MI (B: 430.23, 95% CI: 52.41; 808.04, p = 0.026) mapped onto increased CAR. No statistically significant associations between the CAR and patient-evaluated PSS or the HDRS and the YMRS, respectively were found. There was no statistically significant effect of smartphone-based treatment on the CAR.

CONCLUSION

Our data, of preliminary character, found smartphone-based patient-evaluations of stress and mood instability as read outs that reflect CAR dynamics. Smartphone-supported clinical care did not in itself appear to disturb CAR dynamics.

The Role of Stress in Bipolar Disorder

Stress is a major risk factor for bipolar disorder. Even though we do not completely understand how stress increases the risk for the onset and poorer course of bipolar disorder, knowledge of stress physiology is rapidly evolving. Following stress, stress hormones - including (nor)adrenaline and corticosteroid - reach the brain and change neuronal function in a time-, region-, and receptor-dependent manner. Stress has direct consequences for a range of cognitive functions which are time-dependent. Directly after stress, emotional processing is increased at the cost of higher brain functions. In the aftermath of stress, the reverse is seen, i.e., increased executive function and contextualization of information. In bipolar disorder, basal corticosteroid levels (under non-stressed conditions) are generally found to be increased with blunted responses in response to experimental stress. Moreover, patients who have bipolar disorder generally show impaired brain function, including reward processing. There is some evidence for a causal role of (dysfunction of) the stress system in the etiology of bipolar disorder and their effects on brain system functionality. However, longitudinal studies investigating the functionality of the stress systems in conjunction with detailed information on the development and course of bipolar disorder are vital to understand in detail how stress increases the risk for bipolar disorder.

Real-time mobile monitoring of bipolar disorder: a review of evidence and future directions

Rapidly accumulating data from mobile assessments are facilitating our ability to track patterns of emotions, behaviors, biologic rhythms, and their contextual influences in real time. These approaches have been widely applied to study the core features, traits, changes in states, and the impact of treatments in bipolar disorder (BD). This paper reviews recent evidence on the application of both passive and active mobile technologies to gain insight into the role of the circadian system and patterns of sleep and motor activity in people with BD. Findings of more than two dozen studies converge in demonstrating a broad range of sleep disturbances, particularly longer duration and variability of sleep patterns, lower average and greater variability of motor activity, and a shift to later peak activity and sleep midpoint, indicative of greater evening orientation among people with BD. The strong associations across the domains tapped by real-time monitoring suggest that future research should shift focus on sleep, physical/motor activity, or circadian patterns to identify common biologic pathways that influence their interrelations. The development of novel data-driven functional analytic tools has enabled the derivation of individualized multilevel dynamic representations of rhythms of multiple homeostatic regulatory systems. These multimodal tools can inform clinical research through identifying heterogeneity of the manifestations of BD and provide more objective indices of treatment response in real-world settings. Collaborative efforts with common protocols for the application of multimodal sensor technology will facilitate our ability to gain deeper insight into mechanisms and multisystem dynamics, as well as environmental, physiologic, and genetic correlates of BD.

Neuroendocrine Stress System in Bipolar Disorder

Hormones have a crucial part in the progress and manifestation of a wide variety of different behaviors. The main influence of the neuroendocrine system on behavior is its action on the neurobiology of neuropsychiatric disorders and its relationship with the pharmacodynamics of medicines. Of all the neuroendocrine axes, the hypothalamic-pituitary-adrenal (HPA) axis has been the most extensively studied. There is evidence that disturbance in the HPA axis, the primary stress hormone system, could increase treatment resistance and relapse, worsen illness outcome, and cause cognitive deficits. Glucocorticoids mediate their actions in negative feedback binding in two different cytoplasmatic receptors described as mineralocorticoid receptors (MRs) and glucocorticoid receptors (GRs). Different psychopathologies underlying bipolar disorders are supposed to involve persistent dysfunctions in the expression and role of both MR and GR in the hippocampus. We review and analyze the evidence related to the correlation between bipolar disorders and the consequences and impact of stressful life events on the HPA axis, exploring the importance of these findings in bipolar disorders and as potential new targets for treatment.

Urinary Cortisol Increases During a Respiratory Outbreak in Wild Chimpanzees

Abstract: In mammals, the excretion of cortisol can provide energy toward restoring homeostasis and is a major component of the stress response. However, chronically elevated cortisol levels also have suppressive effects on immune function. As mounting an immune response is energetically costly, sick individuals may conserve energy by exhibiting certain sickness behaviors, such as declining activity levels. Due to the complex interplay between immune function and sickness behaviors, endocrinological correlates have received growing attention in the medical community, but so far, this subject was investigated rarely. Furthermore, given the complexities of studying illnesses and immunity in natural settings, correlates of sickness behaviors have yet to be studied in non-human primates in the wild.

Methods: We measured urinary cortisol levels using liquid chromatography–mass spectrometry in a group of wild habituated chimpanzees in Taï National Park, Côte d'Ivoire, before, during, and after a respiratory disease outbreak (main causative pathogen: human respiratory syncytial virus A, with coinfections of Streptococcus pneumoniae). Changes in cortisol levels were then related to urinary neopterin levels, a biomarker of immune system activation.

Results: Urinary cortisol levels were found to be more than 10-fold higher during the outbreak in comparison with levels before and after the outbreak period. Increasing cortisol levels were also associated with increasing neopterin levels. Interestingly, rather atypical patterns in a diurnal decline of cortisol levels were found during infection periods, such that levels remained raised throughout the day.

Conclusion: In conclusion, cortisol increase was related to cellular immune response. Our results suggest that cortisol is a mediator of infectious disease pathogenicity through its impact on the immune system and that wild chimpanzees may be facing energetic stress when sick. By monitoring immune challenges in wild-living animals, our study demonstrates that immune defenses have costs and that these costs are context-specific.

Role of biological rhythm dysfunction in the development and management of bipolar disorders: a review

Disturbance of biological rhythms contributes to the onset of bipolar disorders and is an important clinical feature of the condition. To further explore the role of biological rhythms in bipolar disorders, 95 English articles published between 1968 and 2019 were retrieved from the PubMed database and analysed. We herein review the outcomes of studies on biological rhythm disturbance in bipolar disorders, including the epidemiology, aetiology, clinical features (eg, sleep, feeding and eating disorders) and treatment of the condition evaluated by patients’ self-report and biological indicators such as melatonin. Our report supports the characterisation of biological rhythm disturbance as a significant clinical feature affecting the onset and development of bipolar disorders and reviews classical and novel treatments, such as chronotherapy, that can be applied in the clinical practice. Our analysis indicates that a more comprehensive study of the pathophysiology, clinical phenomenology and treatment of biological rhythm disturbance is required.

Compliance and Retention With the Experience Sampling Method Over the Continuum of Severe Mental Disorders: Meta-Analysis and Recommendations

Background

Despite the growing interest in the experience sampling method (ESM) as a data collection tool for mental health research, the absence of methodological guidelines related to its use has resulted in a large heterogeneity of designs. Concomitantly, the potential effects of the design on the response behavior of the participants remain largely unknown.

Objective

The objective of this meta-analysis was to investigate the associations between various sample and design characteristics and the compliance and retention rates of studies using ESM in mental health research.

Methods

ESM studies investigating major depressive disorder, bipolar disorder, and psychotic disorder were considered for inclusion. Besides the compliance and retention rates, a number of sample and design characteristics of the selected studies were collected to assess their potential relationships with the compliance and retention rates. Multilevel random/mixed effects models were used for the analyses.

Results

Compliance and retention rates were lower for studies with a higher proportion of male participants (P<.001) and individuals with a psychotic disorder (P<.001). Compliance was positively associated with the use of a fixed sampling scheme (P=.02), higher incentives (P=.03), higher time intervals between successive evaluations (P=.02), and fewer evaluations per day (P=.008), while no significant associations were observed with regard to the mean age of the sample, the study duration, or other design characteristics.

Conclusions

The findings demonstrate that ESM studies can be carried out in mental health research, but the quality of the data collection depends upon a number of factors related to the design of ESM studies and the samples under study that need to be considered when designing such protocols.

Use of ecological momentary assessment to detect variability in mood, sleep and stress in bipolar disorder

Objective

Our aim was to study within-person variability in mood, cognition, energy, and impulsivity measured in an Ecological Momentary Assessment paradigm in bipolar disorder by using modern statistical techniques. Exploratory analyses tested the relationship between bipolar disorder symptoms and hours of sleep, and levels of pain, social and task-based stress. We report an analysis of data from a two-arm, parallel group study (bipolar disorder group N = 10 and healthy control group N = 10, with 70% completion rate of 14-day surveys). Surveys of bipolar disorder symptoms, social stressors and sleep hours were completed on a smartphone at unexpected times in an Ecological Momentary Assessment paradigm twice a day. Multi-level models adjusted for potential subject heterogeneity were adopted to test the difference between the bipolar disorder and health control groups.

Results

Within-person variability of mood, energy, speed of thoughts, impulsivity, pain and perception of skill of tasks was significantly higher in the bipolar disorder group compared to health controls. Elevated bipolar disorder symptom domains in the evening were associated with reduced sleep time that night. Stressors were associated with worsening of bipolar disorder symptoms. Detection of symptoms when an individual is experiencing difficulty allows personalized, focused interventions.

Differences in beliefs about mood between people with and without bipolar disorder

Psychological models of bipolar disorder (BD), such as the self-regulation model (SRM; Leventhal, Nerenz, & Steele, 1984), highlight the crucial role of beliefs about mood in relapse vulnerability. To date, no studies have directly compared these beliefs between people with and without BD. Based on the SRM, the current research examined beliefs about mood in people with and without BD and explored the impact of current affect on these beliefs. Fifty euthymic people with a diagnosis of BD and 50 controls were recruited through an online screening study, clinical services, and support organizations. Experience sampling methodology (ESM) was used to assess beliefs (according to the Brief Illness Perceptions Questionnaire; Broadbent, Petrie, Main, & Weinman, 2006) across a typical week of everyday life. Data were analysed using multilevel modelling. Forty-two people with a diagnosis of BD and 50 controls were included in the analyses. Results indicated that the BD group reported less control over mood, a shorter duration of mood, and less understanding of mood and were more likely to report the cause of depressive symptoms as something internal, compared with controls. When controlling for current affect, the BD group also reported more positive consequences, made more internal attributions for hypomanic symptoms, and reported less concern about mood, compared with controls. Findings suggest important differences in beliefs about mood between people with and without BD that are not the result of current affect. These beliefs may be particularly important in understanding underlying vulnerability to future relapse into depression and/or mania.

Investigating associations between momentary stress and cortisol in daily life: What have we learned so far?

Since cortisol measurement in saliva has been established, it has been used as an indicator of stress-related hypothalamic-pituitary-adrenocortical axis activity. Concurrent development of methodological frameworks such as ambulatory assessment, ecological momentary assessment, and experience sampling have provided opportunities to combine both approaches in daily life research. The current review provides a summary of basic methodological principles and recommendations, as well as abstracts of findings of studies investigating momentary associations between stress and cortisol in daily life with an emphasis on within-subject associations (i.e. average covariance in repeated momentary assessments of stress and cortisol, and individual-specific deviations from the average covariance). Methodological challenges related to stress measurement, sampling principles, and appropriate statistical modeling are discussed, followed by a description of the historical development of studies on within-subject associations between momentary daily life stress and cortisol. The review concludes with a discussion of controversial methodological characteristics of these studies regarding operationalizations of stress, compliance, timing and frequency of stress and cortisol sampling, and reporting of effect sizes. Future research in this area would benefit from automated cortisol assessment, broadening of the scope of stress response measures, use of advanced statistical models that better account for dynamics in the stress process in daily life, and attempts to replicate findings. While previous studies of momentary stress and concurrent cortisol assessments have reliably confirmed some fundamental predictions from stress theory in daily life, future studies should aim at providing progress by testing innovative research questions and utilizing new technological developments.

Cortisol levels in fingernails, neurocognitive performance and clinical variables in euthymic bipolar I disorder

OBJECTIVES

Neurocognitive impairment has been found in bipolar patients. Hypercortisolemia is one possible cause but there has been no agreement on this. Previous sampling methods assessed only acute cortisol levels, whereas the association between cortisol and psychopathology might be better understood by investigating chronic levels. Fingernails are a novel method for measuring chronic cortisol concentration (CCC). Here, we measured CCC in euthymic bipolar disorder I (BD-I) patients and healthy controls using fingernails to investigate whether differences in CCC influenced neurocognitive performance. We also investigated whether differences in clinical illness variables influenced CCC in euthymic BD-I patients.

METHODS

A previous study demonstrated neurocognitive impairment in euthymic BD-I patients. The current study included a portion of this sample: 40 BD-I versus 42 matched controls who provided fingernail samples.

RESULTS

There was no statistically significant difference in CCC between controls and BD-I (P = .09). Logistic regression analyses revealed that euthymic bipolar I subjects with more than five years of current euthymia had decreased odds of having higher fingernail cortisol concentration (>71.2 pg/mg) compared to those with less than 1.5 years (P = .04). There was no association between CCC and cognitive impairment in all domains before and after adjustment for age and sex.

CONCLUSIONS

The current evidence suggests CCC is not a trait biomarker in euthymic BD-I (BD-I). Longer periods of stability in affective disorders are associated with lower CCC. Fingernail cortisol does not seem to be implicated in neurocognitive impairment and BD-I. Future studies may investigate CCC in different illness phases of BD-I.

Social stress response in adolescents with bipolar disorder

OBJECTIVE

Theoretical models posit that stressors contribute to the onset and maintenance of bipolar disorder in adolescence through disruptions in stress physiology, but physiological response to stressors has not been evaluated in adolescents with bipolar illness. The present study tests the hypothesis that adolescents with bipolar disorder will have greater reactivity to a laboratory social stress task than healthy adolescents.

METHOD

Adolescents with bipolar illness (n = 27) and healthy adolescents (n = 28) completed a modified version of the Trier Social Stress Task. Stress response was assessed using high frequency heart rate variability (HF-HRV), heart rate (HR), mean arterial blood pressure (MAP), salivary cortisol, and subjective stress. Multilevel models were used to test for group differences in resting-state physiology, and stress reactivity and recovery.

RESULTS

Adolescents with bipolar disorder had greater reactivity in HF-HRV (z = 3.32), but blunted reactivity in MAP (z = -3.08) and cortisol (z = -2.60), during the stressor compared to healthy adolescents. They also had lower resting HF-HRV (z = -3.49) and cortisol (z = -2.86), and higher resting HR (z = 3.56), than healthy adolescents.

CONCLUSIONS

These results indicate that bipolar disorder is associated with disruptions in autonomic and endocrine response to stress during adolescence, including greater HF-HRV reactivity. Further research should evaluate whether these individual differences in stress physiology precede and predict the onset of mood episodes.

The relationship between inflammatory state and quantity of affective episodes in bipolar disorder

OBJECTIVES

Immunological/inflammatory processes have been proposed to play an important role in the pathophysiology of mood disorders, including bipolar disorder (BD). The present study aimed to examine the influence of immune activation, measured on the basis of inflammatory markers, on the course of illness, proxied by the number of affective episodes, in patients with BD.

METHODS

We investigated the relationship between high-sensitive CRP (hsCRP) and Interleukin 6 (IL-6), two inflammatory markers and characteristics of course of illness (e.g. number of affective episodes, depressive and manic symptoms) amongst a group of 190 individuals with BD.

RESULTS

Among females with BD, there was a positive correlation between levels of hsCRP and the number of manic and depressive episodes. Moreover, levels of hsCRP and IL-6 were positively correlated with current manic symptoms, as measured by Young-Mania-Rating-Scale. There were no significant correlations between levels of the foregoing inflammatory markers, and manic and depressive symptoms in male individuals with BD. Furthermore, compared to their untreated counterparts, female patients treated with lithium demonstrated higher levels of hsCRP and male patients treated with atypical antipsychotics lower levels of hsCRP, respectively.

CONCLUSIONS

Our results are suggesting that the association between inflammatory state and affective response in patients with BD may be gender-dependent. A future research would be to evaluate whether or not these gender differences can be observed in other inflammatory pathways associated with BD.

Cortisol awakening response in patients with bipolar disorder during acute episodes and partial remission: A pilot study

This exploratory study examined the cortisol awakening response (CAR) in patients with bipolar disorder (BPD) at acute phases and partial remission of manic or depressive episodes. Saliva samples of twenty-seven BPD inpatients and 25 healthy controls were collected to determine the CAR patterns, and 12 patients were sampled again at partial remission. BPD patients exhibited a non-enhanced CAR pattern. Lower cortisol expression and a blunted CAR distinguished bipolar-depressive patients from the controls. The intra-individual follow-up for both patient groups revealed a non-significant improvement in CAR patterns, indicating a trend of a normalized CAR after partial remission for BPD patients.

Corticosterone oscillations during mania induction in the lateral hypothalamic kindled rat-Experimental observations and mathematical modeling

Changes in the hypothalamic-pituitary-adrenal (HPA) axis activity constitute a key component of bipolar mania, but the extent and nature of these alterations are not fully understood. We use here the lateral hypothalamic-kindled (LHK) rat model to deliberately induce an acute manic-like episode and measure serum corticosterone concentrations to assess changes in HPA axis activity. A mathematical model is developed to succinctly describe the entwined biochemical transformations that underlay the HPA axis and emulate by numerical simulations the considerable increase in serum corticosterone concentration induced by LHK. Synergistic combination of the LHK rat model and dynamical systems theory allows us to quantitatively characterize changes in HPA axis activity under controlled induction of acute manic-like states and provides a framework to study in silico how the dynamic integration of neurochemical transformations underlying the HPA axis is disrupted in these states.

Physical Activity Modulates Common Neuroplasticity Substrates in Major Depressive and Bipolar Disorder

Mood disorders (MDs) are chronic, recurrent mental diseases that affect millions of individuals worldwide. Although the biogenic amine model has provided some clinical utility, a need remains to better understand the interrelated mechanisms that contribute to neuroplasticity deficits in MDs and the means by which various therapeutics mitigate them. Of those therapeutics being investigated, physical activity (PA) has shown clear and consistent promise. Accordingly, the aims of this review are to (1) explicate key modulators, processes, and interactions that impinge upon multiple susceptibility points to effectuate neuroplasticity deficits in MDs; (2) explore the putative mechanisms by which PA mitigates these features; (3) review protocols used to induce the positive effects of PA in MDs; and (4) highlight implications for clinicians and researchers.

Hyper- and hypocortisolism in bipolar disorder - A beneficial influence of lithium on the HPA-axis?

BACKGROUND

A hyperactive hypothalamic-pituitary-adrenal axis (HPA-axis) is a well-known phenomenon in bipolar disorder (BD). However, hypocortisolism has also been described and found associated with depression, low quality of life and cardiovascular risk factors in BD patients. Although the pathophysiology related to hypocortisolism in BD is largely unknown, hypocortisolism is associated with chronic stress exposure and after inducing an initial rise in cortisol long-term stress may result in a transition to hypocortisolism. BD patients are throughout life often exposed to chronic stress. We therefore hypothesized that higher age would be associated with lower HPA-axis activity especially among patients without previous mood stabilizing treatment.

METHODS

This cross-sectional study consisted of 159 bipolar outpatients and 258 controls. A low-dose-dexamethasone-suppression-test (DST) was used to measure HPA-axis activity.

RESULTS

Patients with BD showed a negative association between post DST cortisol and age (-3.0 nmol/l per year; p=0.007). This association gradually increased in subgroups that were naïve to lithium (-7.7 nmol/l per year; p=0.001) and "all mood stabilizers" (-11.4 nmol/l per year; p=0.004). Patients exhibiting hypercortisolism were characterized by younger age and female gender, whereas patients exhibiting hypocortisolism were characterized by long disease duration without prophylactic lithium treatment as well as absence of current lithium medication.

LIMITATIONS

Cross sectional study design.

CONCLUSIONS

There was a negative association between HPA-axis activity and age in BD, rendering BD patients at risk for developing hypocortisolism. This association was most pronounced among patients without previous or current lithium prophylaxis.

Medical comorbidity in bipolar disorder: The link with metabolic-inflammatory systems

BACKGROUND

Bipolar disorder (BD) is associated with chronic low-grade inflammation, several medical comorbidities and a decreased life expectancy. Metabolic-inflammatory changes have been postulated as one of the main links between BD and medical comorbidity, although there are few studies exploring possible mechanisms underlying this relationship. Therefore, the aims of the current narrative review were 1) synthesize the evidence for metabolic-inflammatory changes that may facilitate the link between medical comorbidity and BD and 2) discuss therapeutic and preventive implications of these pathways.

METHODS

The PubMed and Google Scholar databases were searched for relevant studies.

RESULTS

Identified studies suggested that there is an increased risk of medical comorbidities, such as autoimmune disorders, obesity, diabetes and cardiovascular disease in patients with BD. The association between BD and general medical comorbidities seems to be bidirectional and potentially mediated by immune dysfunction. Targeting the metabolic-inflammatory-mood pathway may potential yield improved outcomes in BD; however, further study is needed to determine which specific interventions may be beneficial.

LIMITATIONS

The majority of identified studies had cross-sectional designs, small sample sizes and limited measurements of inflammation.

CONCLUSIONS

Treatment and prevention of general medical comorbidities in mood disorders should include preferential prescribing of metabolically neutral agents and adjunctive lifestyle modifications including increased physical activity, improved diet and decreased substance abuse. In addition, the use of anti-inflammatory agents could be a relevant therapeutic target in future research.

A comparison of neurometabolites between remitted bipolar disorder and depressed bipolar disorder: A proton magnetic resonance spectroscopy study

BACKGROUND

Recent many studies found the abnormal neurometabolites in the acute bipolar disorder (BD). However, limited studies were to detect neurometabolites in remitted BD, comparison between acute and remitted BD is conductive to understand the outcome of neurometabolites. This study sought to investigate the differences in neurometabolites between remitted and depressed BD patients using proton magnetic resonance spectroscopy (¹H-MRS).

METHODS

Three subject groups were enrolled: 22 remitted BD patients, 22 depressed BD patients and 24 healthy controls. All subjects underwent ¹H-MRS to measure N-acetylaspartate (NAA), Choline (Cho), myo-Inositol (mI) and Creatine (Cr) of several bilateral areas potentially involved in BD: prefrontal whiter matter (PWM), thalamus and putamen. The neurometabolite ratios were compared among three groups. The correlations between abnormal neurometabolite ratios and clinical data were computed.

RESULTS

The lower bilateral PWM NAA/Cr ratios were found in depressed BD patients than remitted BD patients and healthy controls, no differences were found between the remitted BD patients and controls. For depressed BD patients, left PWM NAA/Cr ratios showed negative correlation with age of onset, right PWM NAA/Cr ratios showed positive correlation with duration of illness.

CONCLUSIONS

Our findings suggest the abnormal neurometabolites in the prefrontal lobe whiter may occur in the depressed BD. The remitted BD may resemble healthy subjects in terms of neurometabolites. In addition, abnormal neurometabolites in prefrontal lobe whiter may correlate with the age of onset and illness length.

Multifactorial discrimination as a fundamental cause of mental health inequities

BACKGROUND

The theory of fundamental causes explains why health disparities persist over time, even as risk factors, mechanisms, and diseases change. Using an intersectional framework, we evaluated multifactorial discrimination as a fundamental cause of mental health disparities.

METHODS

Using baseline data from the Project STRIDE: Stress, Identity, and Mental Health study, we examined the health effects of discrimination among individuals who self-identified as lesbian, gay, or bisexual. We used logistic and linear regression to assess whether multifactorial discrimination met the four criteria designating a fundamental cause, namely that the cause: 1) influences multiple health outcomes, 2) affects multiple risk factors, 3) involves access to resources that can be leveraged to reduce consequences of disease, and 4) reproduces itself in varied contexts through changing mechanisms.

RESULTS

Multifactorial discrimination predicted high depression scores, psychological well-being, and substance use disorder diagnosis. Discrimination was positively associated with risk factors for high depression scores: chronic strain and total number of stressful life events. Discrimination was associated with significantly lower levels of mastery and self-esteem, protective factors for depressive symptomatology. Even after controlling for risk factors, discrimination remained a significant predictor for high depression scores. Among subjects with low depression scores, multifactorial discrimination also predicted anxiety and aggregate mental health scores.

CONCLUSIONS

Multifactorial discrimination should be considered a fundamental cause of mental health inequities and may be an important cause of broad health disparities among populations with intersecting social identities.

Intra-individual cortisol variability and low-grade inflammation over 10 years in older adults

OBJECTIVE

This study examined the associations between intra-individual variability in, and inter-individual levels of, diurnal cortisol secretion with a marker of low-grade inflammation (i.e., C-Reactive Protein; CRP). Reasoning that greater day-to-day cortisol variability could reflect a dysregulation of the HPA axis, we hypothesized that it would predict higher levels of CRP, above and beyond inter-individual differences in cortisol levels.

METHODS

A 10-year longitudinal study of 130 older adults examined diurnal cortisol secretion on three different days across each of the 6 waves of data collection and levels of CRP during the last 3 waves. Indicators of mean cortisol levels, short-term cortisol variability, and long-term cortisol variability were analyzed.

RESULTS

Hierarchical linear modeling showed significant main effects, linking baseline mean cortisol levels, T-ratio=2.25, p=0.03, and long-term cortisol variability, T-ratio=2.63, p=0.01, with higher CRP values six to ten years after study entry. In addition, a two-way interaction demonstrated that short-term variability in cortisol were associated with higher levels of CRP among individuals who secreted relatively high, T-ratio=2.68, p=0.01, but not low, T-ratio=-1.09, p=0.28, baseline levels of cortisol. Finally, a three-way interaction, T-ratio=2.24, p=0.03, suggested that the effect of long-term cortisol variability on CRP became stronger over time among participants who secreted high average levels of cortisol, whereas it became weaker among their counterparts who secreted low average levels of cortisol.

CONCLUSION

Variability in cortisol secretion across days forecasts low-grade inflammation, and this association is paramount among older adults who secrete high levels of diurnal cortisol.

Threat sensitivity in bipolar disorder

Life stress is a major predictor of the course of bipolar disorder. Few studies have used laboratory paradigms to examine stress reactivity in bipolar disorder, and none have assessed autonomic reactivity to laboratory stressors. In the present investigation we sought to address this gap in the literature. Participants, 27 diagnosed with bipolar I disorder and 24 controls with no history of mood disorder, were asked to complete a complex working memory task presented as "a test of general intelligence." Self-reported emotions were assessed at baseline and after participants were given task instructions; autonomic physiology was assessed at baseline and continuously during the stressor task. Compared to controls, individuals with bipolar disorder reported greater increases in pretask anxiety from baseline and showed greater cardiovascular threat reactivity during the task. Group differences in cardiovascular threat reactivity were significantly correlated with comorbid anxiety in the bipolar group. Our results suggest that a multimethod approach to assessing stress reactivity-including the use of physiological parameters that differentiate between maladaptive and adaptive profiles of stress responding-can yield valuable information regarding stress sensitivity and its associations with negative affectivity in bipolar disorder. (PsycINFO Database Record (c) 2015 APA, all rights reserved).

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.

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.

Neither cortisol nor brain-derived neurotrophic factor is associated with serotonin transporter in bipolar disorder

Converging evidence indicates the hypothalamus-pituitary-adrenal axis and serotonergic neurons exert reciprocal modulatory actions. Likewise, brain-derived neurotrophic factor (BDNF) has been implicated as a growth and differentiation factor in the development of serotonergic neurons. The aim of this study was to examine the interaction of cortisol and BDNF on serotonin transporter (SERT) in bipolar disorder (BD). Twenty-eight BD and 28 age- and gender-matched healthy controls (HCs) were recruited. (123)I-ADAM with single-photon emission computed tomography (SPECT) was applied for measurement of SERT availability in the brain, which included the midbrain, thalamus, putamen and caudate. Ten milliliters of venous blood was withdrawn, when the subject underwent SPECT, for the measurement of the plasma concentration of cortisol and BDNF. SERT availability was significantly decreased in the midbrain and caudate of BD compared with HCs, whereas plasma concentration of cortisol and BDNF did not show a significant difference. The linear mixed-effect model revealed that there was a significant interaction of group and cortisol on SERT availability of the midbrain, but not BDNF. Linear regression analyses by groups revealed that cortisol was associated with SERT availability in the midbrain in the HCs, but not in BD. Considering previous studies, which showed a significant association of cortisol with SERT availability in the HCs and major depressive disorder (MDD), our result replicated a similar finding in HCs. However, the negative finding of the association of cortisol and SERT availability in BD, which was different from MDD, suggests a different role for cortisol in the pathophysiology of mood disorder.

Daily mood monitoring of symptoms using smartphones in bipolar disorder: A pilot study assessing the feasibility of ecological momentary assessment

BACKGROUND

Personal device technology has facilitated gathering data in real-time using Ecological momentary assessment (EMA). We hypothesized that using smartphones to measure symptoms in auto-generated surveys twice a day would be feasible in a group with bipolar disorder (BD). A second exploratory objective of this study was to compare potential differences in core symptoms between BD and healthy control (HC) groups.

METHODS

A two-arm, parallel group, observational study was designed to measure completion rates of surveys of symptoms of mood, energy, speed of thought, impulsivity, and social stress in BD (N=10) and HC (N=10) participants. The surveys were auto-generated twice a day for fourteen days, and subjects could also perform self-generated surveys. Completion rates were compared between BD and HC groups. Scores were averaged for each participant over the 14 day period, and group medians were compared.

RESULTS

Median completion rates did not differ between groups: 95% in BD, 88% in HC (p=0.68); the median completion rate of auto-generated surveys in the BD group was 79% and in the HC group was 71% (p=0.22). The BD group had significantly lower median mood score (p=0.043) and energy score (p=0.007) than the HC group. Median scores of speed of thoughts (p=0.739), impulsivity (p=0.123) and social stress (p=0.056) did not significantly differ between BD and HC. The BD group had significantly higher range of variability of group median mood (p=0.043), speed of thoughts (p=0.002) and impulsivity (p=0.005) scores over the course of 14 days than HC, while range of variability of energy (p=0.218) and social stress (p=0.123) scores did not differ. Results were not significantly different between auto-generated and self-generated surveys for BD or HC.

LIMITATIONS

This pilot study was conducted for a short time and with a small sample.

CONCLUSIONS

This study demonstrates feasibility of using EMA with a smartphone to gather data on BD symptoms.

Bipolar Disorder: Role of Inflammation and the Development of Disease Biomarkers

Bipolar disorder is a severe and enduring psychiatric condition which in many cases starts during early adulthood and follows a relapsing and remitting course throughout life. In many patients the disease follows a progressive path with brief periods of inter-episode recovery, sub-threshold symptoms, treatment resistance and increasing functional impairment in the biopsychosocial domains. Knowledge about the neurobiology of bipolar disorder is increasing steadily and evidence from several lines of research implicates immuno-inflammatory mechanisms in the brain and periphery in the etiopathogenesis of this illness and its comorbidities. The main findings are an increase in the levels of proinflammatory cytokines during acute episodes with a decrease in neurotrophic support. Related to these factors are glial cell dysfunction, neuro-endocrine abnormalities and neurotransmitter aberrations which together cause plastic changes in the mood regulating areas of the brain and neuroprogression of the bipolar diathesis. Research in the above mentioned areas is providing an opportunity to discover novel biomarkers for the disease and the field is reaching a point where major breakthroughs can be expected in the not too distant future. It is hoped that with new discoveries fresh avenues will be found to better treat an otherwise recalcitrant disease.

Intraindividual Cortisol Variability and Psychological Functioning in Caregivers of Hematopoietic Stem Cell Transplant Patients

OBJECTIVE

Caregiving for allogeneic hematopoietic stem cell transplant (Allo-HSCT) patients carries a significant psychological burden, yet it remains unclear whether Allo-HSCT caregivers demonstrate disruptions to stress systems, such as the hypothalamic-pituitary-adrenal axis. Greater intraindividual cortisol variability (ICV) has been observed in psychiatric disorders; however, there is a knowledge gap evaluating ICV in caregivers. We predicted that greater ICV would be related to poorer mental health in Allo-HSCT caregivers.

METHODS

Allo-HSCT caregivers (n = 140) collected saliva for 3 consecutive days at 4 time points/d. Psychological variables included sleep quality and a summary composite score of overall mental health.

RESULTS

Regression analyses demonstrated that greater ICV was significantly related to poorer overall mental health (β = 0.25, p = .009), whereas poorer sleep did not reach significance (β = 0.16, p = .069). No significant relationships emerged for the cortisol area under the curve, diurnal decline, or awakening response.

CONCLUSIONS

Results extend prior work examining ICV as a unique marker that is possibly more sensitive than other widely applied measures of hypothalamic-pituitary-adrenal axis dysregulation to a distressed population of caregivers.

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.

Stress management reduces intraindividual cortisol variability, while not impacting other measures of cortisol rhythm, in a group of women at risk for breast cancer

OBJECTIVE

The stress hormone cortisol exhibits a diurnal rhythm throughout the day, as well as within person variability. Recent statistical approaches allow for the estimation of intraindividual cortisol variability ("ICV") and a greater ICV has been observed in some mood disorders (major depression, remitted bipolar disorder); however, ICV has not been examined following stress management. In this secondary analyses of an efficacious randomized clinical trial, we examine how ICV may change after cognitive behavioral stress management (CBSM) among healthy stressed women at risk for breast cancer. Second, we concurrently compare other calculations of cortisol that may change following CBSM.

METHODS

Multilevel modeling (MLM) was applied to estimate ICV and to test for a group by time interaction from baseline, post-intervention, to 1 month following CBSM. Forty-four women were randomized to the CBSM; 47 to the comparison group; mean age of the entire group was 44.2 (SD=10.27).

RESULTS

After controlling for relevant covariates, a significant time by group interaction emerged (β estimate=-.070; p<.05), such that CBSM participants demonstrated a lower ICV following CBSM compared to the comparison group. The interaction for cortisol slope and cortisol output (area under the curve) approached significance (β estimates=-.10 and -.062, respectively; p's<.08), while other cortisol outcomes tested were not significantly changed following CBSM.

CONCLUSION

ICV may represent a novel index of cortisol dysregulation that is impacted by CBSM and may represent a more malleable within-person calculation than other, widely applied cortisol outcomes. Future research should examine these relationships in larger samples, and examine ICV and health outcomes.

CLINICAL TRIALS IDENTIFIER

NCT01048528.

The bipolarity of light and dark: A review on Bipolar Disorder and circadian cycles

BACKGROUND

Bipolar Disorder is characterized by episodes running the full mood spectrum, from mania to depression. Between mood episodes, residual symptoms remain, as sleep alterations, circadian cycle disturbances, emotional deregulation, cognitive impairment and increased risk for comorbidities. The present review intends to reflect about the most recent and relevant information concerning the biunivocal relation between bipolar disorder and circadian cycles.

METHODS

It was conducted a literature search on PubMed database using the search terms "bipolar", "circadian", "melatonin", "cortisol", "body temperature", "Clock gene", "Bmal1 gene", "Per gene", "Cry gene", "GSK3β", "chronotype", "light therapy", "dark therapy", "sleep deprivation", "lithum" and "agomelatine". Search results were manually reviewed, and pertinent studies were selected for inclusion as appropriate.

RESULTS

Several studies support the relationship between bipolar disorder and circadian cycles, discussing alterations in melatonin, body temperature and cortisol rhythms; disruption of sleep/wake cycle; variations of clock genes; and chronotype. Some therapeutics for bipolar disorder directed to the circadian cycles disturbances are also discussed, including lithium carbonate, agomelatine, light therapy, dark therapy, sleep deprivation and interpersonal and social rhythm therapy.

LIMITATIONS

This review provides a summary of an extensive research for the relevant literature on this theme, not a patient-wise meta-analysis.

CONCLUSIONS

In the future, it is essential to achieve a better understanding of the relation between bipolar disorder and the circadian system. It is required to establish new treatment protocols, combining psychotherapy, therapies targeting the circadian rhythms and the latest drugs, in order to reduce the risk of relapse and improve affective behaviour.

Ecological momentary assessment (EMA) of depression-related phenomena

Ecological momentary assessment (EMA) is one research method increasingly employed to better understand the processes that underpin depression and related phenomena. In particular, EMA is well suited to the study of affect (e.g., positive and negative affect), affective responses to stress (e.g., emotion reactivity), and behaviors (e.g., activity level, sleep) that are associated with depression. Additionally, EMA can provide insights into self-harm behavior (i.e. suicide and non-suicidal self-injury), and other mood disorders (e.g. bipolar disorder) commonly associated with depressive episodes. Given the increasing availability and affordability of handheld computing devices such as smartphones, EMA is likely to play an increasingly important role in the study of depression and related phenomena in the future.

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.

Recent negative life events increase hair cortisol concentrations in patients with bipolar disorder

Life events induce stress, which is considered to negatively impact the course of disease in patients with bipolar disorder (BD), its effects being predominantly mediated by cortisol. Cortisol in scalp hair has been identified as a biomarker for assessing long-term cortisol levels, and allows clarifying the relation between life events, hair cortisol concentrations (HCC), and clinical course over time. In 71 BD patients, we analyzed the proximal 3 cm of hair, reflecting 3 months of cortisol production, and investigated the association between HCC, the number of life events, the amount of social support, and mood in the 3 months prior to the hair assessment and between HCC and mood in the subsequent 3 months. Although the total number of life events was not associated with HCC (p > 0.05), the number of negative life events was associated with increased HCC (r(2)( )= 0.04, p = 0.02). Social support showed an inverse association with HCC in patients reporting negative life events (r(2)( )= 0.07, p = 0.03). HCC and mood were not associated in the 3 months prior to hair sampling or in the subsequent 3 months. This study indicates that patients who experienced recent negative life events have increased hair cortisol levels, which seem to be attenuated by social support.

Associations between self-reported discrimination and diurnal cortisol rhythms among young adults: The moderating role of racial-ethnic minority status

Discrimination is theorized to set in motion a neuroendocrine response, which includes cortisol secretion from the hypothalamic-pituitary-adrenal axis. Repeated exposure to perceived discrimination is thought to contribute to alterations in diurnal cortisol rhythms and to have implications for health. Discrimination may have particularly strong effects on racial/ethnic minority individuals, based on histories of past exposure and/or greater perceived implications of discriminatory events. Utilizing an ethnically and racially diverse sample of young adults (N=140; Mage=22.8 years) and a multiple-day naturalistic cortisol protocol, the present study examined associations between self-reported discrimination and diurnal cortisol rhythms, and whether this relation was moderated by racial/ethnic minority status. Results revealed that self-reported discrimination predicted flatter diurnal cortisol slopes for racial/ethnic minority individuals only. These findings align with theory suggesting that discrimination experiences are important among racial/ethnic minorities.

Morning cortisol levels in schizophrenia and bipolar disorder: a meta-analysis

Increased peripheral levels of morning cortisol have been reported in people with schizophrenia (SZ) and bipolar disorder (BD), but findings are inconsistent and few studies have conducted direct comparisons of these disorders. We undertook a meta-analysis of studies examining single measures of morning cortisol (before 10 a.m.) levels in SZ or BD, compared to controls, and to each other; we also sought to examine likely moderators of any observed effects by clinical and demographic variables. Included studies were obtained via systematic searches conducted using Medline, BIOSIS Previews and Embase databases, as well as hand searching. The decision to include or exclude studies, data extraction and quality assessment was completed in duplicate by LG, SM and AS. The initial search revealed 1459 records. Subsequently, 914 were excluded on reading the abstract because they did not meet one or more of the inclusion criteria; of the remaining 545 studies screened in full, included studies were 44 comparing SZ with controls, 19 comparing BD with controls, and 7 studies directly comparing schizophrenia with bipolar disorder. Meta-analysis of SZ (N=2613, g=0.387, p=0.001) and BD (N=704, g=0.269, p=0.004) revealed moderate quality evidence of increased morning cortisol levels in each group compared to controls, but no difference between the two disorders (N=392, g=0.038, p=0.738). Subgroup analyses revealed greater effect sizes for schizophrenia samples with an established diagnosis (as opposed to 'first-episode'), those that were free of medication, and those sampled in an inpatient setting (perhaps reflecting an acute illness phase). In BD, greater morning cortisol levels were found in outpatient and non-manic participants (as opposed to those in a manic state), relative to controls. Neither age nor sex affected cortisol levels in any group. However, earlier greater increases in SZ morning cortisol were evident in samples taken before 8 a.m. (relative to those taken after 8 a.m.). Multiple meta-regression showed that medication status was significantly associated with morning cortisol levels in SZ, when the effects of assay method, sampling time and illness stage were held constant. Heightened levels of morning cortisol in SZ and BD suggest long-term pathology of the hypothalamic-pituitary-adrenal (HPA) axis that may reflect a shared process of illness development in line with current stress-vulnerability models.

Cytokines in bipolar disorder: paving the way for neuroprogression

Bipolar disorder (BD) is a severe, chronic, and recurrent psychiatric illness. It has been associated with high prevalence of medical comorbidities and cognitive impairment. Its neurobiology is not completely understood, but recent evidence has shown a wide range of immune changes. Cytokines are proteins involved in the regulation and the orchestration of the immune response. We performed a review on the involvement of cytokines in BD. We also discuss the cytokines involvement in the neuroprogression of BD. It has been demonstrated that increased expression of cytokines in the central nervous system in postmortem studies is in line with the elevated circulating levels of proinflammatory cytokines in BD patients. The proinflammatory profile and the immune imbalance in BD might be regarded as potential targets to the development of new therapeutic strategies.