Salivary cortisol secretion in remitted bipolar patients and offspring of bipolar parents

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.

Dim light melatonin patterns in unaffected offspring of parents with bipolar disorder: A case-control high-risk study

BACKGROUND

Circadian dysregulation has long been thought to be a key component in the pathophysiology of bipolar disorder (BD). However, it remains unclear whether this dysregulation constitutes a risk factor, manifestation, or consequence of BD. This study aimed to compare dim light melatonin secretion patterns between unaffected offspring of parents with BD (OBD) and offspring of control parents (OCP).

METHODS

This case-control study included unaffected OBD (mean age 14.0 years; male 50.0 %) and age- and sex-matched OCP (mean age 13.0 years; male: 43.5 %). Seventeen saliva samples were collected in dim light conditions. Dim light melatonin onset (DLMO), phase angles, and area under the curve (AUC) were calculated.

RESULTS

185 saliva samples from 12 OBD (n = 12) and 741 from OCP (n = 46) were collected. Unaffected OBD had a significant lower nocturnal melatonin level (14.8 ± 4.6 vs. 20.3 ± 11.7 pg/mL) and a smaller melatonin AUC within two hours after DLMO (35.5 ± 11.3 vs. 44.6 ± 18.1 pg/mL) but a significant larger phase angle between DLMO and sleep onset (2.2 ± 1.0 vs. 1.4 ± 1.2 h) than OCP. There was no significant between-group difference in DLMO. The graphic illustrations showed a considerably flattened melatonin secretion in unaffected OBD.

LIMITATIONS

The main limitations include lack of 24-h dim melatonin secretion measurement, large age range of participants, and small sample size.

CONCLUSIONS

These findings suggest that unaffected OBD already presented with circadian rhythm dysregulations. Future investigations are needed to clarify the role of abnormal melatonin secretion in the onset of BD.

Cortisol awakening response in bipolar patients with comorbid type 2 diabetes mellitus

OBJECTIVES

Bipolar disorder (BD) is frequently associated with type 2 diabetes mellitus (T2DM). The functioning of the hypothalamic-pituitary-adrenal (HPA) axis has been never investigated in BD with respect to the glucose metabolic status. Therefore, we assessed the cortisol awakening response (CAR) in bipolar patients with or without comorbid T2DM.

METHODS

Twenty euglycemic bipolar patients [12 males and eight females; mean age (±SD): 47.4 ± 14.4 years; mean (±SD) duration of illness: 18.3 ± 12.1 years], 16 BD patients with T2DM [11 males and five females; mean age (±SD): 63.6 ± 12.8 years; mean (±SD) duration of bipolar illness: 17.1 ± 10.8 years; mean (±SD) duration of T2DM: 5.2 ± 5.3 years], 18 healthy subjects [seven males and 11 females; mean age (±SD): 45.0 ± 12.1 years] and 12 non-psychiatric subjects with T2DM [eight males and four females; mean age (±SD): 56.7 ± 11.2 years; mean (±SD) duration of T2DM: 5.2 ± 3.5 years] were recruited. Saliva cortisol was measured at awakening and after 15, 30, and 60 min.

RESULTS

With respect to both healthy controls and controls with T2DM, euglycemic and diabetic BD patients exhibited a CAR occurring at significantly lower levels. No significant difference emerged in the CAR between the two groups of bipolar patients. Controls with T2DM had an overall post-awakening cortisol production significantly higher than healthy controls.

CONCLUSIONS

Our results show that the CAR of patients with BD is reduced in terms of overall cortisol production but normal in terms of cortisol reactivity independently from the occurrence of comorbid T2DM. The dampened CAR points to a tuning down of the functioning of the HPA axis. in both euglycemic and diabetic BD patients, which may be a factor of vulnerability, since a preserved HPA axis functioning is essential to deal with stressors, which may precipitate affective episodes.

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.

Dysregulated Diurnal Cortisol Pattern and Heightened Night-Time Cortisol in Individuals with Bipolar Disorder

INTRODUCTION

Hypothalamic-pituitary-adrenal (HPA) axis dysregulation may contribute to the symptom burden in bipolar disorder (BD). Further characterization of cortisol secretion is needed to improve understanding of the connection between mood, sleep, and the HPA axis. Here, we observe diurnal cortisol patterns in individuals with BD and healthy controls (HCs) to determine time points where differences may occur.

METHODS

Salivary cortisol was measured at 6 time points (wake, 15, 30, and 45 min after wake, between 2:00 and 4:00 p.m. and 10:00 p.m.) for 3 consecutive days in individuals with symptomatic BD (N = 27) and HC participants (N = 31). A general linear model with correlated errors was utilized to determine if salivary cortisol changed differently throughout the day between the 2 study groups.

RESULTS

A significant interaction (F = 2.74, df = 5, and p = 0.02) was observed between the time of day and the study group (BD vs. HC) when modeling salivary cortisol over time, indicating that salivary cortisol levels throughout the day significantly differed between the study groups. Specifically, salivary cortisol in BD was elevated compared to HCs at the 10:00 p.m. time point (p = 0.01).

CONCLUSION

Significantly higher levels of cortisol in participants with BD in the night-time suggest that the attenuation of cortisol observed in healthy individuals may be impaired in those with BD. Reregulation of cortisol levels may be a target of further study and treatment intervention for individuals with BD.

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.

Cortisol as a Biomarker of Mental Disorder Severity

Cortisol—the most important steroid hormone with a significant effect on body metabolism—strongly affects peripheral tissues and the central nervous system. Fluctuations in cortisol secretion often accompany psychiatric disorders, and normalization of its levels correlates with improvement in the patient’s health. This indicates that cortisol may be useful as a biological marker that can help determine the likelihood of mental illness, its impending onset, and the severity of symptoms, which is especially important in the face of the increasing prevalence of mental disorders, including those associated with social isolation and anxiety during the COVID-19 pandemic. This publication reviews recent reports on cortisol levels in healthy participants and shows the current state of knowledge on changes in the levels of this hormone in people at risk for depression, bipolar disorder, and psychosis. It shows how people with psychiatric disorders react to stressful situations and how the applied therapies affect cortisol secretion. The influence of antidepressants and antipsychotics on cortisol levels in healthy people and those with mental disorders is also described. Finally, it reviews publications on the patterns of cortisol secretion in patients in remission.

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.

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.

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.

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.

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.

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.

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.

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.

Toward a comprehensive clinical staging model for bipolar disorder: integrating the evidence

OBJECTIVES

To describe key findings relating to the natural history and heterogeneity of bipolar disorder (BD) relevant to the development of a unitary clinical staging model. Currently proposed staging models are briefly discussed, highlighting complementary findings, and a comprehensive staging model of BD is proposed integrating the relevant evidence.

METHOD

A selective review of key published findings addressing the natural history, heterogeneity, and clinical staging models of BD are discussed.

RESULTS

The concept of BD has broadened, resulting in an increased spectrum of disorders subsumed under this diagnostic category. Different staging models for BD have been proposed based on the early psychosis literature, studies of patients with established BD, and prospective studies of the offspring of parents with BD. The overarching finding is that there are identifiable sequential clinical phases in the development of BD that differ in important ways between classical episodic and psychotic spectrum subtypes. In addition, in the context of familial risk, early risk syndromes add important predictive value and inform the staging model for BD.

CONCLUSIONS

A comprehensive clinical staging model of BD can be derived from the available evidence and should consider the natural history of BD and the heterogeneity of subtypes. This model will advance both early intervention efforts and neurobiological research.

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.

Personality, coping, risky behavior, and mental disorders in the offspring of parents with bipolar disorder: a comprehensive psychosocial assessment

OBJECTIVES

It has been proposed that the offspring of parents with bipolar disorder (OBD), through genetic mechanisms and early family interactions, develop a heightened sensitivity to stress, maladaptive coping, and dysregulated behavior, which ultimately increases the risk for affective disorders. The current study tested certain predictions of this model by assessing different psychosocial and health-related outcomes in the OBD, including personality, coping style, smoking, suicidality, high-risk sexual behaviors, criminality, and mental health.

METHOD

The sample was composed of 74 OBD and 75 control offspring, who were between 14 and 27 years of age (mean: 19.38±3.56). Participants underwent a diagnostic interview and a structured interview to assess high-risk behavior and other maladaptive outcomes, and they completed the Revised NEO Personality Inventory and Coping in Stressful Situations questionnaire.

RESULTS

The rates of affective (31.1%) and non-affective (56.8%) disorders were elevated in the OBD compared to controls (9.5% and 32.4%). Relative to controls, OBD endorsed fewer task-oriented and more distraction coping strategies [Wilk׳s λ=.83, F(1, 136) =6.92, p<.01], and were more likely to report engaging in high-risk sexual behavior (OR=2.37; Wald=4.13, 1 df, p<05). Importantly, OBD reported elevated high-risk sexual behavior relative to controls, irrespective of affective disorder diagnosis.

CONCLUSION

The results highlight a potential risk profile for the OBD, consisting of ineffective coping strategies and risky sexual behavior and are discussed in the context of current knowledge of stress and coping in this population.

LIMITATIONS

The present findings were based on cross-sectional data and relied on offspring self-report. It would be useful to corroborate these findings with biobehavioural and longitudinal measures.

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.

Hair cortisol, stress exposure, and mental health in humans: a systematic review

The deleterious effects of chronic stress on health and its contribution to the development of mental illness attract broad attention worldwide. An important development in the last few years has been the employment of hair cortisol analysis with its unique possibility to assess the long-term systematic levels of cortisol retrospectively. This review makes a first attempt to systematically synthesize the body of published research on hair cortisol, chronic stress, and mental health. The results of hair cortisol studies are contrasted and integrated with literature on acutely circulating cortisol as measured in bodily fluids, thereby combining cortisol baseline concentration and cortisol reactivity in an attempt to understand the cortisol dynamics in the development and/or maintenance of mental illnesses. The studies on hair cortisol and chronic stress show increased hair cortisol levels in a wide range of contexts/situations (e.g. endurance athletes, shift work, unemployment, chronic pain, stress in neonates, major life events). With respect to mental illnesses, the results differed between diagnoses. In major depression, the hair cortisol concentrations appear to be increased, whereas for bipolar disorder, cortisol concentrations were only increased in patients with a late age-of-onset. In patients with anxiety (generalized anxiety disorder, panic disorder), hair cortisol levels were reported to be decreased. The same holds true for patients with posttraumatic stress disorder, in whom - after an initial increase in cortisol release - the cortisol output decreases below baseline. The effect sizes are calculated when descriptive statistics are provided, to enable preliminary comparisons across the different laboratories. For exposure to chronic stressors, the effect sizes on hair cortisol levels were medium to large, whereas for psychopathology, the effect sizes were small to medium. This is a first implication that the dysregulation of the hypothalamic-pituitary-adrenal (HPA) axis in the development and/or maintenance of psychopathology may be more subtle than it is in healthy but chronically stressed populations. Future research possibilities regarding the application of hair cortisol research in mental health and the need for multidisciplinary approaches are discussed.

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.

Hypothalamic-pituitary-adrenal axis and clinical symptoms in first-episode psychosis

BACKGROUND

Abnormalities in hypothalamic-pituitary-adrenal (HPA) axis activity have been reported in patients with psychosis, but it is still unclear how these are related to the clinical symptomatology. Inconsistent findings have emerged from previous studies on the association between cortisol levels and clinical symptoms. Methodological and/or clinical factors, such as patients' diagnosis or illness phase, might partially account for these inconsistencies. The aim of this study was to investigate the association between HPA axis activity and clinical symptoms in first-episode psychosis, taking into account diagnosis and illness phase.

METHOD

Saliva samples were collected in 55 subjects with first-episode psychosis to assess the Cortisol Awakening Response (CAR) and diurnal cortisol levels (AUC-DAY). Severity of symptoms was assessed with the Positive and Negative Syndrome Scale (PANSS). Scores for subscales and symptom dimensions were used as predictors in multivariate analyses in different diagnostic subgroups and in clinically remitted patients. In addition, a systematic review of the literature on this topic was conducted.

RESULTS

In subjects with schizophrenia (n=36), the CAR was predicted by the severity of positive symptoms (beta=0.47, p=0.04); in subjects with depressive psychoses (n=8) the CAR was predicted by excitement (beta=0.58, p=0.005), disorganization (beta=0.39, p=0.007) and depressive symptoms (beta=0.32, p=0.005). In patients with bipolar psychoses (n=11) AUC-DAY was predicted negatively by disorganization (beta=-2.82, p=0.009) and positively by excitement (beta=2.06, p=0.009) and positive symptoms (beta=1.28, p=0.02). In the sample in clinical remission (n=9), the CAR was associated with the severity of positive symptoms (beta=1.34, p=0.009) and, negatively, with excitement (beta=-1.05, p=0.04). The systematic review (on a total of 28 papers, including n=1022 patients), found that in patients with psychosis cortisol levels have been associated with the severity of multiple symptom dimensions.

CONCLUSIONS

HPA axis activity is associated with the severity of multiple types of symptoms in first-episode psychosis. Patients' diagnosis and clinical phase partially influence these associations.

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.

Salivary cortisol in ambulatory assessment--some dos, some don'ts, and some open questions

The impact of stress on health and disease is an important research topic in psychosomatic medicine. Because research on hypothalamic-pituitary-adrenal (HPA) axis regulation under controlled laboratory studies lacks ecological validity, it needs to be complemented by a research program that includes momentary ambulatory assessment. The measurement of salivary cortisol offers the possibility to trace the free steroid hormone concentrations in ambulant settings. Therefore, in this article, we first discuss the role of salivary cortisol in ambulatory monitoring. We start with a brief description of HPA axis regulation, and we then consider cortisol assessments in other organic materials, followed by a presentation of common salivary markers of HPA axis regulation suitable for ambulatory assessment. We further provide an overview on assessment designs and sources of variability within and between subjects (intervening variables), acknowledge the issue of (non)compliance, and address statistical aspects. We further give an overview of associations with psychosocial and health-related variables relevant for ambulatory assessment. Finally, we deal with preanalytical aspects of laboratory salivary cortisol analysis. The relative simplicity of salivary cortisol assessment protocols may lead to an overoptimistic view of the robustness of this method. We thus discuss several important issues related to the collection and storage of saliva samples and present empirical data on the stability of salivary cortisol measurements over time.

The relationship between subtypes of depression and cardiovascular disease: a systematic review of biological models

A compelling association has been observed between cardiovascular disease (CVD) and depression, suggesting individuals with depression to be at significantly higher risk for CVD and CVD-related mortality. Systemic immune activation, hypothalamic-pituitary-adrenal (HPA) axis hyperactivity, arterial stiffness and endothelial dysfunction have been frequently implicated in this relationship. Although a differential epidemiological association between CVD and depression subtypes is evident, it has not been determined if this indicates subtype specific biological mechanisms. A comprehensive systematic literature search was conducted using PubMed and PsycINFO databases yielding 147 articles for this review. A complex pattern of systemic immune activation, endothelial dysfunction and HPA axis hyperactivity is suggestive of the biological relationship between CVD and depression subtypes. The findings of this review suggest that diagnostic subtypes rather than a unifying model of depression should be considered when investigating the bidirectional biological relationship between CVD and depression. The suggested model of a subtype-specific biological relationship between depression and CVDs has implications for future research and possibly for diagnostic and therapeutic processes.

Associations between suicide attempts and elevated bedtime salivary cortisol levels in bipolar disorder

BACKGROUND

Hypothalamic-pituitary-adrenal (HPA) axis abnormalities have been reported in bipolar disorder and also in suicidal behavior, but few studies have examined the relationship between suicidal behaviors and the HPA axis function in bipolar disorder, attending to and minimizing confounding factors. We compare HPA axis activity in bipolar individuals with and without suicidal behavior and unaffected healthy controls through measurement of salivary cortisol.

METHOD

Salivary cortisol was collected for three consecutive days in 29 controls, 80 bipolar individuals without a history of suicide and 56 bipolar individuals with a past history of suicide. Clinical factors that affect salivary cortisol were also examined.

RESULTS

A past history of suicide was associated with a 7.4% higher bedtime salivary cortisol level in bipolar individuals. There was no statistical difference between non-suicidal bipolar individuals and controls in bedtime salivary cortisol and awakening salivary cortisol was not different between the three groups.

LIMITATIONS

The measure of salivary cortisol was a home based collection by the study subjects and the retrospective clinical data was primarily based on their historical account.

CONCLUSIONS

Bipolar individuals with a past history of suicidal behavior exhibit hyperactivity in the HPA axis. This biological marker remains significant regardless of demographic factors, mood state, severity and course of illness. This finding in bipolar disorder is consistent with the evidence for altered HPA axis functioning in suicide and mood disorders and is associated with a clinical subgroup of bipolar patients at elevated risk for suicide based on their history, and in need of further attention and study.

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.

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.

Sex-specific cortisol levels in bipolar disorder and schizophrenia during mental challenge--relationship to clinical characteristics and medication

OBJECTIVE

Our objective was to examine the cortisol release during a mental challenge in severe mental disorders versus healthy controls (HC), analyzing effects of sex, clinical characteristics and medication, and comparing Bipolar Disorder (BD) to Schizophrenia (SCZ).

METHODS

Patients with BD and SCZ (n=151) were recruited from a catchment area. HC (n=98) were randomly selected from the same area. Salivary samples were collected before and after a mental challenge and cortisol levels determined.

RESULTS

During the challenge there was an interaction between group and sex (P = 0.015) with male patients having a blunted cortisol release compared to male HC (P = 0.037). Cortisol change did not differ significantly between BD and SCZ. In all patients, the cortisol change correlated with number of psychotic episodes (r = -0.23, P = 0.025), and in females patients, with number of depressive episodes (r = -0.33, P = 0.015). Patients using antidepressants had a greater cortisol release during challenge than those not using antidepressants (P = 0.043).

CONCLUSIONS

Male patients with severe mental disorders seem to have a uniform abnormal cortisol release during mental challenges which associates with clinical course, and with beneficial effects of antidepressants.

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

Previous studies on bipolar disorder revealed abnormalities in the function of the HPA axis, including disturbed patterns of cortisol secretion, during depressive and manic episodes. It is less clear whether these abnormalities persist after symptomatic recovery. In the present study we used the experience sampling method with intensive salivary cortisol sampling to study patterns of cortisol secretion in relation to negative and positive daily events during the normal daily life of a group of 36 patients with remitted bipolar disorder and 38 healthy controls. Results of multilevel regression analysis indicated that daytime cortisol levels and reactivity to daily events were similar in remitted bipolar patients and healthy controls, but bipolar patients showed flatter diurnal slopes and larger cortisol fluctuations over successive measures. Patients with many previous episodes had higher overall cortisol levels, reduced cortisol reactivity to negative daily events, and flatter diurnal slopes than patients with fewer episodes. These results provide additional evidence of subtle HPA axis dysregulation in remitted bipolar patients, especially in those with many recurrent episodes.

Salivary cortisol in depressed patients versus control persons: a systematic review and meta-analysis

The pathophysiology of depression has been associated to dysregulation of the hypothalamic-pituitary-adrenal axis and the use of salivary cortisol measures is increasingly being incorporated into research. The aim of the present study was to investigate whether salivary cortisol differs for patients with depression and control persons. We did a systematic review with sequential meta-analysis and meta-regression according to the PRISMA Statement based on comprehensive database searches for studies of depressed patients compared to control persons in whom salivary cortisol was measured. Twenty case-control studies, including 1354 patients with depression and 1052 control persons were identified. In a random-effects meta-analysis salivary cortisol was increased for depressed patients as compared to control persons on average 2.58 nmol/l (95% C.I.: 0.95-4.21) p=0.002 in the morning and on average 0.27 nmol/l (95% C.I.: 0.03-0.51) p=0.03 in the evening. In a fixed-effects model the mean difference was 0.58 nmol/l (95% C.I.). Study sequential cumulative meta-analyses suggested random error for the finding of this rather small difference between groups. The reference intervals for morning salivary cortisol in depressed patients (0-29 nmol/l) and control persons (1-23 nmol/l) showed substantial overlap suggesting lack of discriminative capacity. These results should be interpreted with caution as the heterogeneity for the morning analysis was large and a funnel plot, suggested presence of bias. Further, in meta-regression analyses higher intra-assay coefficients of variation in cortisol kits (p=0.07) and mean age (p=0.08) were associated with a higher mean difference of morning salivary cortisol between depressed and controls, while gender and depression severity were not. Based on the available studies there is not firm evidence for a difference of salivary cortisol in depressed patients and control persons and salivary cortisol is unable to discriminate between persons with and without depression.

The early stages of bipolar disorder and recent developments in the understanding of its neurobiology

Bipolar disorder is a severe recurrent psychiatric illness that often manifests in adolescence, a time of marked neurobiological change. The current model is one of multiple susceptibility genes interacting with other risk factors leading to alterations in the normal maturational trajectory of the CNS. Longitudinal studies of children of affected parents has enabled mapping of the early natural history of bipolar disorder. Convergent evidence from longitudinal high-risk studies suggest that bipolar disorder evolves in a series of clinical stages from nonspecific childhood disorders to depressive disorders in early adolescence and bipolar spectrum disorders in later adolescence and adulthood. At present, genetic studies and research into specific biological markers in bipolar patients and their family members are underway. Advances in understanding the neurobiological underpinnings of bipolar disorder will require addressing etiological heterogeneity of bipolar disorder and refining the phenotypic definition. In the latter case, the staging model may be a helpful organizing framework.

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

OBJECTIVES

The hypothalamic-pituitary-adrenal (HPA) axis is compromised in major depression, bipolar disorder (BD), and in the offspring of parents with major depression. Less is known about the offspring of parents with BD (FH+). The present project provides follow-up to a previous study showing that the adolescent (mean age 16.7 years) FH+ offspring had higher salivary cortisol levels than the offspring of parents with no mental disorder (FH-) throughout the day in their natural environment, and that girls had higher cortisol levels than boys (Ellenbogen MA, Hodgins S, Walker C-D, Adam S, Couture S. Daytime cortisol and stress reactivity in the offspring of parents with bipolar disorder. Psychoneuroendocrinology 2006; 31: 1164-1180). The goal of the present study was to determine whether FH+ offspring, approximately two years later, continued to exhibit elevated cortisol levels relative to FH- offspring during two weeks of daily sampling.

METHODS

The present study examined salivary cortisol levels in 24 (18.3 +/- 2.6 years) FH+ and 22 (18.0 +/- 2.3 years) FH- offspring who are part of the same longitudinal cohort as the previous study. Saliva was collected at 1300 h and 1500 h in the natural environment of the offspring during 14 consecutive days.

RESULTS

Multilevel modelling analyses indicated that FH+ offspring had higher afternoon levels of cortisol in their natural environment than FH- offspring, but group differences in slope and gender differences were not found.

CONCLUSIONS

The FH+ offspring exhibited increased daytime secretion of cortisol that, at the level of the group, persisted into late adolescence and young adulthood. Perhaps this change in HPA functioning is associated with an increased vulnerability for the development of an affective disorder.

Human models in acute and chronic stress: assessing determinants of individual hypothalamus-pituitary-adrenal axis activity and reactivity

Stress is one of the most significant health problems in modern societies and the 21st century. This explains a pressing need for investigations into the biological pathways linking stress and health. Besides the locus coeruleus-noradrenaline/autonomic (sympathetic) nervous system ( Chrousos and Gold 1992 ), the hypothalamus-pituitary-adrenal (HPA) axis is the major physiological stress response system in the body. Since alterations in HPA axis regulation under basal conditions and in response to acute stress appear to be a close correlate or even a determining factor of the onset of different diseases or disease progression ( Holsboer 1989 ; Chrousos and Gold 1992 ; Tsigos and Chrousos 1994, 2002 ; Stratakis and Chrousos 1995 ; McEwen 1998 ; Heim et al. 2000a ; Raison and Miller 2003 ), the characterization of an individual's HPA axis activity as well as reactivity pattern to psychosocial stress appears to be of major interest. It is obvious that such a research agenda substantially depends on the availability of appropriate measures. However, since the HPA axis is a highly adaptive system which is characterized by marked inter- and intraindividual variability ( Mason 1968 ; Hellhammer et al. 2009 ), the development of such markers of HPA axis regulation in humans was-and still is-a rather challenging task. In this brief review, we focus on findings on two HPA axis measures, namely the cortisol-awakening response (CAR) to assess HPA axis basal activity and the Trier social stress test (TSST) to investigate HPA axis stress reactivity.

Rationale and design of the participant, investigator, observer, and data-analyst-blinded randomized AGENDA trial on associations between gene-polymorphisms, endophenotypes for depression and antidepressive intervention: the effect of escitalopram versus placebo on the combined dexamethasone-corticotrophine releasing hormone test and other potential endophenotypes in healthy first-degree relatives of persons with depression

BACKGROUND

Endophenotypes are heritable markers, which are more prevalent in patients and their healthy relatives than in the general population. Recent studies point at disturbed regulation of the hypothalamic-pituitary-adrenocortical axis as a possible endophenotype for depression. We hypothesize that potential endophenotypes for depression may be affected by selective serotonin re-uptake inhibitor antidepressants in healthy first-degree relatives of depressed patients. The primary outcome measure is the change in plasma cortisol in the dexamethasone-corticotrophin releasing hormone test from baseline to the end of intervention.

METHODS

The AGENDA trial is designed as a participant, investigator, observer, and data-analyst-blinded randomized trial. Participants are 80 healthy first-degree relatives of patients with depression. Participants are randomized to escitalopram 10 mg per day versus placebo for four weeks. Randomization is stratified by gender and age. The primary outcome measure is the change in plasma cortisol in the dexamethasone-corticotrophin releasing hormone test at entry before intervention to after four weeks of intervention. With the inclusion of 80 participants, a 60% power is obtained to detect a clinically relevant difference in the primary outcome between the intervention and the placebo group. Secondary outcome measures are changes from baseline to four weeks in scores of: 1) cognition and 2) neuroticism. Tertiary outcomes measures are changes from baseline to four weeks in scores of: 1) depression and anxiety symptoms; 2) subjective evaluations of depressive symptoms, perceived stress, quality of life, aggression, sleep, and pain; and 3) salivary cortisol at eight different timepoints during an ordinary day. Assessments are undertaken by assessors blinded to the randomization group.

Salivary cortisol in unaffected twins discordant for affective disorder

Dysfunction in the hypothalamic-pituitary-adrenal (HPA) axis has been proposed as a biological endophenotype for affective disorders. In the present study the hypothesis that a high genetic liability to affective disorder is associated with higher cortisol levels was tested in a cross-sectional high-risk study. Healthy monozygotic (MZ) and dizygotic (DZ) twins with (High-Risk twins) and without (Low-Risk twins) a co-twin history of affective disorder were identified through nationwide registers. Awakening and evening salivary cortisol levels were compared between the 190 High- and Low-Risk twins. The 109 High-Risk twins had significantly higher evening cortisol levels than the 81 Low-Risk MZ twins, also after adjustment for age, sex, and the level of subclinical depressive symptoms. No significant difference was found in awakening cortisol levels between High-Risk and Low-Risk twins. In conclusion, a high genetic liability to affective disorder was associated with a higher evening cortisol level, but not with awakening cortisol level. Future prospective family, high-risk and twin studies are needed to decide whether abnormalities in the HPA axis can be identified as an endophenotype of affective disorder.