The 24-hour profiles of cortisol, prolactin, and growth hormone secretion in mania

A review of potential cognitive and environmental risk markers in children of bipolar parents

Although there is clear evidence that bipolar disorder runs in families, the mechanisms by which this illness is transmitted across generations are poorly understood. In particular, there has been limited consideration of nature of the psychosocial risk factors that might be present in offspring of bipolar parents and of how these factors might increase the likelihood of transition to illness. Recent research has begun to explore psychosocial factors in both healthy and diagnosed children of bipolar parents. This review explores the findings that have been obtained to date in terms of personality, cognitive functioning, life events and family factors. Three potential theoretical frameworks are then considered which might prove fruitful for facilitating theoretically driven empirical studies in this important area. Implications for future research and therapy are noted.

The role of circadian clock genes in mental disorders

The study of molecular clock mechanisms in psychiatric disorders is gaining significant interest due to data suggesting that a misalignment between the endogenous circadian system and the sleep-wake cycle might contribute to the clinical status of patients suffering from a variety of psychiatric disorders. Sleep disturbances in major depressive disorder (MDD) are characterized by increased sleep latency, poorer sleep efficiency, reduced latency to the first rapid eye movement (REM) sleep episode, and early-morning awakening, but there is little data to indicate a role of circadian clock genes in MDD. There is also relatively little information regarding the role of clock genes in anxiety. In contrast, a significant amount of evidence gathered in bipolar disorder (BPD) patients suggests a circadian rhythm disorder, namely an advanced circadian rhythm and state-dependent alterations of REM sleep latency. Most research on the role of clock genes in BPD has focused on polymorphisms of CLOCK, but the lithium target GSK3 may also play a significant role. A circadian phase shift is also theorized to contribute to the pathophysiology of winter seasonal affective disorder (SAD). Certain allelic combinations of NPAS2, PER3, and BMAL1 appear to contribute to the risk of SAD. In chronic shizophrenia, disturbances of sleep including insomnia and reduced sleep efficiency have been observed. Genetic studies have found associations with CLOCK, PER1, PER3, and TIMELESS. Sleep and circadian changes associated with dementia due to Alzheimer's disease suggest a functional change in the circadian master clock, which is supported by postmortem studies of clock gene expression in the brain.

Single nucleotide polymorphism analysis of corticotropin-releasing factor-binding protein gene in bipolar disorder

Corticotropin-releasing factor-binding protein regulates the availability of free corticotropin-releasing factor and is a functional candidate gene for affective disorders. The aim of this study was to examine the association between polymorphisms in CRF-BP gene and bipolar disorder in an isolated Swedish population. One hundred and eighty-two patients with bipolar I disorder and 333 controls from Northern Sweden were included in the study. Five single nucleotide polymorphisms and a deletion polymorphism in the CRF-BP gene were genotyped. The haplotype block structure of the gene was considered and the expectation maximization algorithm was adopted to estimate the haplotype frequencies. As a result, there were no significant associations of the different polymorphisms in the CRF-BP gene with bipolar disorder. In conclusion, this study in an isolated Swedish population does not support a role for the CRF-BP gene in the vulnerability for bipolar disorder.

Age-related differences in glucocorticoid receptor mRNA levels in the human brain

Glucocorticoids and their receptors (GRs) are implicated in dynamic cognitive and neuroendocrine processes mediated by the prefrontal cortex and hippocampus. Additionally, a primary defect in forebrain GR levels can mimic symptoms of depression. We hypothesized that changes in GR mRNA levels may occur in the human brain across the life span thus positioning GR to differentially influence behavior and disease susceptibility. Following in situ hybridization with a riboprobe for human GR mRNA, we employed quantitative film autoradiography to measure expression levels in the prefrontal cortex and hippocampus in five age groups (infants, adolescents, young adults, adults, and aged) and in primary visual and visual association cortices for comparison. We detected a main effect of age group on cortical, but not hippocampal GR mRNA, with greater cortical expression in adolescents and adults than in infants or the aged. Increased GR mRNA in prefrontal cortex during adolescence and adulthood suggests that human GR-mediated forebrain regulation of cognition and the neuroendocrine stress response may be more salient during late maturation and at maturity.

Seasonal influences on first-episode admission in affective and non-affective psychosis

BACKGROUND

Since bipolar affective disorder has been recorded, clinicians treating patients with this disorder have noted the cyclic nature of episodes, particularly an increase in mania in the spring and summer months and depression during winter.

OBJECTIVE

The aim of this study was to investigate seasonality in symptom onset and service admissions over a period of 10 years in a group of patients (n= 359) with first-episode (FE) mania (n= 133), FE schizoaffective disorder (n= 49) and FE schizophrenia (n= 177).

METHOD

Patients were recruited if they were between 15 and 28 years of age and if they resided in the geographical mental health service catchment area. The number of patients experiencing symptom onset and service admission over each month and season was recorded.

RESULTS

In terms of seasonality of time of service admission, the results indicate a high overall seasonality (particularly in men), which was observed in both the schizoaffective and the bipolar groups. In terms of seasonality of symptom onset, the results indicate that seasonality remains in the male bipolar group, but other groups have no seasonal trend.

CONCLUSIONS

This provides further evidence that systems mediating the entrainment of biological rhythms to the environment may be more pronounced in BPAD than in schizoaffective disorder and schizophrenia. These results may help facilitate the preparedness of mental heath services for patients at different times of the year.

Cytokine profiles in bipolar affective disorder: focus on acutely ill patients

BACKGROUND

The role of the immune system in mood disorders is predominately supported by studies in unipolar major depression. However activation of the immune system has also been demonstrated in bipolar mania. Our study examines pro-inflammatory and anti-inflammatory cytokines in both phases of bipolar affective disorder (BPAD).

METHODS

Plasma concentrations of IL-6, IL-8, IL-10, TNF-alpha and sIL-6R were measured with enzyme linked immunosorbent assays (ELISA) in patients with BPAD who were depressed, or manic and in healthy controls.

RESULTS

Bipolar depression had significantly higher production of the pro-inflammatory cytokines, IL-8 (p < 0.001) and TNF-alpha (p < 0.05) compared to healthy subjects. The manic group also had increased production of IL-8 (p < 0.05) and TNF-alpha (p < 0.001) as compared to healthy subjects. Anti-inflammatory cytokine levels did not differ across the 3 groups.

LIMITATIONS

A small sample size was studied. All patients remained on medication for this study.

CONCLUSIONS

BPAD is associated with increased production of pro-inflammatory cytokines both in the manic and in the depressed phase as compared to healthy subjects. This is the first study, which examined both mania and bipolar depression.

Increased pituitary volume in antipsychotic-free and antipsychotic-treated patients of the AEsop first-onset psychosis study

Subjects at their first psychotic episode show an enlarged volume of the pituitary gland, but whether this is due to hypothalamic-pituitary-adrenal (HPA) axis hyperactivity, or to stimulation of the prolactin-secreting cells by antipsychotic treatment, is unclear. We measured pituitary volume, using 1.5-mm, coronal, 1.5 T, high-resolution MRI images, in 78 patients at the first psychotic episode and 78 age- and gender-matched healthy controls. In all, 18 patients were antipsychotic-free (12 of these were antipsychotic-naïve), 26 were receiving atypical antipsychotics, and 33 were receiving typical antipsychotics. As hypothesized, patients had a larger pituitary volume than controls (+22%, p< 0.001). When divided by antipsychotic treatment, and compared to controls, the pituitary volume was 15% larger in antipsychotic-free patients (p=0.028), 17% larger in patients receiving atypicals (p=0.01), and 30% larger in patients receiving typicals (p<0.001). Patients receiving typicals not only had the largest pituitary volume compared to controls but also showed a trend for a larger pituitary volume compared to the other patients grouped together (+11%, p=0.08). When divided by diagnosis, and compared to controls, the pituitary volume was 24% larger in patients with schizophrenia/schizophreniform disorder (n=40, p<0.001), 19% larger in depressed patients (n=13, p=0.022), 16% larger in bipolar patients (n=16, p=0.037), and 12% larger in those with other psychoses (n=9, p=0.2). In conclusion, the first-episode of a psychotic disorder is associated with a larger pituitary independently of the presence of antipsychotic treatment, and this could be due to activation of the HPA axis. Typical antipsychotics exert an additional enlarging effect on pituitary volume, likely to be related to activation of prolactin-secreting cells. This activation of the hormonal stress response could participate to the important metabolic abnormalities observed in patients with psychosis.

Evaluation of the effects of lamotrigine, valproate and carbamazepine in a rodent model of mania

Bipolar disorder is a psychiatric condition characterised by episodes of mania, depression, and underlying mood instability. Anticonvulsant drugs have an established place in the treatment of the disorder, but identifying novel drugs in this class is complicated by the absence of validated animal models. We have evaluated the efficacy of three anticonvulsant mood stabilising drugs (lamotrigine, valproate, and carbamazepine) in a model of mania, in which hyperactivity is induced by the combination of D-amphetamine and chlordiazepoxide. All three drugs were effective at preventing the hyperactivity. Lower doses of valproate and carbamazepine were required to prevent hyperactivity compared to doses required to block tonic-clonic seizures induced by pentylenetetrazole. Lamotrigine was equipotent in the two models. However, the complex pharmacology of the D-amphetamine/chlordiazepoxide model means that there may be several mechanisms by which hyperactivity can be reduced, and these may have more or less relevance to the treatment of bipolar disorder. To address this issue, we also evaluated effects of the three anticonvulsants on baseline locomotion, on activity in the presence of chlordiazepoxide alone, or on activity induced by D-amphetamine alone. Based on the results, we propose that hyperactivity induced by D-amphetamine/chlordiazepoxide may arise through dopaminergic drive coupled with disinhibition caused by low doses of the benzodiazepine. The efficacy of lamotrigine may then arise through a reduction in neuronal excitability or increased glutamate transmission, these latter a consequence of the disinhibition. Carbamazepine may also reduce excitability and glutamate release, but its broader pharmacology, manifested by sedation at higher doses complicates interpretation of its efficacy and reflects its poorer tolerability in the clinic. Valproate may be effective, at least in part, through an enhancement of GABAergic transmission. The predictive validity of the D-amphetamine/chlordiazepoxide model for efficacy in bipolar disorder remains to be established, and research with a wider range of clinically tested drugs is warranted to help validate the model further. In the meantime, the model may be useful for distinguishing novel anticonvulsant drugs with different mechanisms of action.

Actigraphic assessment of circadian activity and sleep patterns in bipolar disorder

OBJECTIVES

Theoretical accounts and psychological interventions for bipolar disorder indicate that disruption of circadian rhythms is important, both in affective episodes and as a vulnerability factor in subsyndromal periods. This study aims at assessing both circadian activity and sleep patterns using actigraphy within a bipolar sample experiencing low levels of subsyndromal symptoms. It is hypothesized that such participants will display circadian activity disruption in spite of low levels of symptoms.

METHODS

This study employed a mixed design with cross-sectional assessment of mood and week-long (7-day) recording of actigraphy data. All clinical participants were psychiatric outpatients within a UK NHS Hospital. Nineteen bipolar patients and 19 age- and gender-matched controls wore an actigraph for 7 days to obtain sleep and circadian activity data. SCID was used to confirm DSM-IV diagnostic status. Self-report measures of mood were obtained from both groups.

RESULTS

Bipolar patients were found to have less stable and more variable circadian activity patterns than controls. Regression analysis indicated that variability alone was a significant independent predictor of diagnostic group. There was evidence from raw activity data that bipolar patients were also less active than controls. These differences were not associated with levels of subsyndromal symptoms. Bipolar patients did not differ from controls on any of the sleep indices used.

CONCLUSIONS

Circadian activity disruption is apparent in bipolar patients even when not acutely ill. This finding is not associated with the presence of sleep disturbance. Should such patterns be replicated interventions to address both circadian instability and individual attributions for the effects of such instability are likely to be relevant to successful psychological interventions.

Reduced glucocorticoid and estrogen receptor alpha messenger ribonucleic acid levels in the amygdala of patients with major mental illness

BACKGROUND

The amygdala is a limbic structure involved in the stress response and the regulation of emotional behaviors, both of which are disrupted in patients with neuropsychiatric illnesses. Because glucocorticoids are mediators of the stress response, we hypothesized that glucocorticoid receptor (GR) messenger ribonucleic acid (mRNA) levels might be altered in the amygdala. We also hypothesized that estrogen receptor alpha (ERalpha) mRNA expression might be altered in the amygdala, on the basis of observed gender differences in mental illness.

METHODS

Using quantitative film autoradiography after in situ hybridization with human GR and ERalpha probes, we measured mRNA levels on adjacent amygdala sections in four groups (n = 15 each of subjects with schizophrenia, major depressive disorder, and bipolar disorder, and unaffected control subjects) provided by the Stanley Consortium.

RESULTS

We detected main effects of diagnosis and exposure to antidepressant medication on the levels of both mRNAs but no main effect of gender. Compared with control subjects, GR mRNA expression was reduced in the basolateral/lateral nuclei in schizophrenia and bipolar disorder. Estrogen receptor alpha mRNA levels were reduced in the basomedial nucleus in major depressive disorder and bipolar disorder.

CONCLUSIONS

Our results support and extend previous findings describing a pattern of steroid hormone mRNA alterations that differs depending on which brain region is being examined in a given mental illness.

Regional specificity of brain glucocorticoid receptor mRNA alterations in subjects with schizophrenia and mood disorders

Glucocorticoid receptors (GR) mediate the direct effects of glucocorticoids released in response to stress and the regulation of the hypothalamic-pituitary-adrenocortical (HPA) system through a negative feedback mechanism. Individuals with major mental illness, who often exhibit hypercortisolemia, may have down-regulated levels of GR mRNA. In situ hybridization for GR mRNA was performed on post-mortem specimens from patients suffering from depression, bipolar disorder, schizophrenia and from normal controls (n = 15 per group). In frontal cortex, GR mRNA levels were decreased in layers III-VI in the subjects with depression and schizophrenia. In inferior temporal cortex, GR mRNA levels were decreased in layer IV in all three diagnostic groups. In the entorhinal cortex, GR mRNA levels were decreased in layers III and VI in the bipolar group. In hippocampus, GR mRNA levels were reduced in the dentate gyrus, CA(4), CA(3) and CA(1) in the schizophrenia group. In the subiculum, GR mRNA levels were reduced in the bipolar group. These results suggest that GR dysregulation occurs in all three major psychiatric illnesses with variability according to anatomical site. The severity and heterogeneity of this reduction may underlie some of the clinical heterogeneity seen in these disorders.

Sleep and the hypothalamo-pituitary-adrenocortical system

The intention of this review is to summarize the current knowledge on the bidirectional interaction between sleep EEG and the secretion of corticotropin (ACTH) and cortisol. The administration of various hypothalamic-pituitary- adrenocortical (HPA) hormones and their antagonists exerts specific sleep-EEG changes in several species including humans. It is well documented that corticotropin releasing hormone (CRH) impairs sleep and enhances vigilance. In addition, it may promote REM sleep. Changes in the growth hormone-releasing hormone (GHRH):CRH ratio in favour of CRH appear to contribute to shallow sleep, elevated cortisol levels and blunted GH in depression and ageing. On the other hand, in women GHRH appears to exert CRH-like effects on sleep. Acute cortisol administration increases slow-wave sleep (SWS) and GH, probably due to feedback inhibition of CRH, and inhibits REM sleep. With the mixed glucocorticoid and progesterone receptor antagonist mifepriston sleep is disrupted. Subchronic administration of the glucocorticoid agonist methylprednisolone desinhibited REM sleep. A synergism of elevated CRH and cortisol activity may contribute to REM disinhibition during depression. Also ACTH and vasopressin modulate sleep specifically but their physiological role remains unclear. For example acute icv vasopressin enhances wakefulness in rats, whereas its long-term administration increases SWS in the elderly. In various studies the interaction of sleep EEG and HPA hormones has been investigated at the baseline, after manipulation of sleep-wake behaviour and after environmental changes. Most studies agree that the circadian pattern of cortisol is relatively independent from sleep and environmental influences. Some data suggest a major effect of light on cortisol secretion. Sleeping is widely associated with blunting and awakenings are linked with increases of HPA hormones.

Circadian rhythms, multilevel models of emotion and bipolar disorder--an initial step towards integration?

This paper sets out possible links between disruption of circadian rhythms in bipolar disorder and the affective symptom, which are experienced in this disorder. Evidence is drawn from Healy and Williams' [Psychiatr. Dev. 1 (1989) 49.] review of circadian function in manic depression, along with later reports, which indicate a role for disrupted circadian rhythms in both depressed and manic phases of manic depression (bipolar disorder). This is integrated within a version of the multilevel model of emotion proposed by Power and Dalgleish [Cognition and emotion: from order to disorder. Hove: Psychology Press (1997); Behav. Cognit. Psychother. 27 (1999) 129.]. The aim of this process is to propose a possible psychological mechanism by which the disruption of circadian rhythms might result in the observed clinical symptoms of bipolar disorder. The integration of these approaches leads to a number of specific testable hypotheses that are relevant to future research into the psychological treatment and understanding of bipolar disorder.

Association and linkage studies of CRH and PENK genes in bipolar disorder: a collaborative IGSLI study

Corticotropin-releasing hormone (CRH) and proenkephalin (PENK) are hypothalamic peptides involved in the stress response and hypothalamic-pituitary axis regulation. Previous research has implicated these peptides in the pathogenesis of affective disorders. In this study we investigated two polymorphisms located in the genes that code for CRH and PENK by means of association and linkage analyses. A total of 138 bipolar patients and 108 controls were included in the association study. In addition, 24 families were available for linkage analysis, including six families of probands with documented periodic positivity of dexamethasone suppression tests (DST) during remission. We found no association of bipolar disorder with either gene. Similarly, we did not find any evidence of linkage (P = 0.56 for CRH and 0.52 for PENK) in the entire sample or in the subsample of families of DST positive probands. In conclusion, our study does not support the hypothesis that genes coding for CRH or PENK contribute to the genetic susceptibility to bipolar disorder. Am. J. Med. Genet. (Neuropsychiatr. Genet.) 96:178-181, 2000.

The citalopram challenge test in patients with major depression and in healthy controls

Neuroendocrine challenge tests in depressed patients have revealed a blunted hormonal reaction to serotonergic stimuli. In the present study, citalopram was chosen as the serotonergic agent for neuroendocrine stimulation. Compared to earlier challenge agents, citalopram has the advantage of serotonergic selectivity, its application is well tolerated and the possibility of intravenous application reduces pharmacokinetic interference. Sixteen patients suffering from an acute episode of major depression and 16 healthy controls underwent the stimulation procedure with 20 mg of citalopram and placebo. Whereas significant differences in the secretion of prolactin and cortisol between citalopram and placebo challenge were observed in the control group, no differences were found in the group of depressed patients. Comparison of depressed patients and controls showed a significantly blunted prolactin secretion in patients. Differences in cortisol secretion following serotonergic stimulation with citalopram did not become significant. The stimulation procedure was well tolerated in all subjects, although a higher number of side effects was observed in the control group. The amount of side effects did not correlate with the hormone responses. These results are in line with the hypothesis of serotonergic hypofunction in depressed patients. In conclusion, the 20-mg citalopram challenge test is thought to be a promising tool for further investigation of serotonergic function in psychiatric illness.

Blunted dexamethasone-induced growth hormone responses in acute mania

Dynamic endocrine testing using a variety of probes has revealed abnormalities of the somatotropic axis in bipolar mania. In health, acute administration of dexamethasone (DEX) results in the secretion of growth hormone (GH) by possibly inhibiting somatostatin tone. We elected to determine DEX/GH responses in acute mania. Eight male bipolar manics were compared with eight age-matched healthy volunteers. Four milligrams of oral DEX was administered at 0900 h (time 0 min) and plasma samples for GH were taken at +60, +180, +240 and +300 min. Baseline samples for GH and cortisol were taken at -15 min and 0 min. Patients had higher basal cortisol levels (391.6 +/- 89.4 nmol/l) as opposed to controls (138.0 +/- 13.2 nmol/l) (paired t-test, t = 4.68, df = 6, p < .0004). The mean (+/- SD) delta GH (calculated as the maximum GH level relative to baseline) in the manic patients was 0.7 +/- 0.8 ng/ml and in the healthy controls was 9.2 +/- 4.3 ng/ml (paired t-test, t = -0.589, df = 6, p < .0001). In conclusion, patients with bipolar mania had lower DEX-induced GH responses in comparison to controls.

Nocturnal ACTH, cortisol, growth hormone, and prolactin secretion in prepubertal depression

OBJECTIVE

To examine nocturnal secretion of adrenocorticotropin, cortisol, growth hormone, and prolactin in 38 medically healthy children with prepubertal major depression compared with 28 medically and psychiatrically healthy control children.

METHOD

Prior to sampling, subjects underwent an "adaptation night" with the intravenous catheter in place and electroencephalographic (EEG) electrodes for standard all-night polysomnogram. On the following night, plasma samples were obtained every 20 minutes through an indwelling catheter. Hormonal concentrations were measured by specific radioimmunoassay and aligned by EEG-confirmed sleep onset. Areas under the curve were calculated for total secretion and compared using analysis of variance.

RESULTS

Prepubertal depressed children had lower cortisol secretion during the first 4 hours after sleep onset compared with controls. Adrenocorticotropin, prolactin, and growth hormone secretion did not differ between groups. Examination of clinical characteristics in depressed children revealed lower nocturnal adrenocorticotropin concentrations in depressed inpatients versus depressed outpatients and in depressed sexually abused versus depressed nonabused children. A significant sex by diagnosis effect revealed lower growth hormone secretion in depressed females compared with depressed males.

CONCLUSIONS

In contrast to neuroendocrine challenge studies in these same subjects, nocturnal neuroendocrine measures did not reveal any of the expected group differences. These results emphasize the contrasts between unstimulated and challenge studies of neuroendocrine secretion and of the importance of considering clinical characteristics and maturation influences in biological studies of prepubertal depression.

Are blunted dexamethasone-induced growth hormone responses unique to depression?

In health, acute administration of glucocorticoids, such as dexamethasone (DEX), leads to growth hormone (GH) secretion. Depression is characterized by blunted DEX/GH responses. In order to determine the specificity of this test for depression we administered 4 mg of oral DEX, to patients with a DSM-III-R diagnosis of depression, schizophrenia, mania and alcohol dependency syndrome. Samples for GH estimation were taken at -15 min, 0 min, +60 min, +180 min, +240 min and +300 min. GH responses were attenuated to a similar degree in depression and mania. Less marked attenuation was seen in schizophrenia while those with alcohol dependency syndrome had GH responses indistinguishable from normal volunteers. Overall, we conclude that subnormal DEX/GH secretion is not specific to depression.

Circadian rhythms and the pharmacology of affective illness

The chronic effects of antidepressant drugs (ADs) on circadian rhythms of behavior, physiology and endocrinology are reviewed. The timekeeping properties of several classes of ADs, including tricyclic antidepressants, selective serotonin reuptake inhibitors, monoamine oxidase inhibitors, serotonin agonists and antagonists, benzodiazepines, and melatonin are reviewed. Pharmacological effects on the circadian amplitude and phase, as well as effects on day-night measurements of motor activity, sleep-wake, body temperature (Tb), 3-methoxy-4-hydroxyphenylglycol, cortisol, thyroid hormone, prolactin, growth hormone and melatonin are examined. ADs often lower nocturnal Tb and affect the homeostatic regulation of sleep. ADs often advance the timing and decrease the amount of slow wave sleep, reduce rapid eye movement sleep and increase or decrease arousal. Together, AD effects on nocturnal Tb and sleep may be related to their therapeutic properties. ADs sometimes delay nocturnal cortisol timing and increase nocturnal melatonin, thyroid hormone and prolactin levels; these effects often vary with diagnosis, and clinical state. The effects of ADs on the coupling of the central circadian pacemaker to photic and nonphotic zeitgebers are discussed.

Growth hormone secretion timing in depression: clinical outcome comparisons

Growth hormone (GH) secretion in the 100 minutes preceding sleep onset (preSO), as well as in the first half of the night (1st HN), was examined for a group of 13 healthy women and 43 women with recurrent depression who participated in a 3-year maintenance therapy study. GH studies were obtained at several points during treatment and every 3 months during maintenance, during which patients were randomly assigned to active drug or drug-free maintenance treatment cells for 3 years, or until recurrence of depression. Depressed patients were divided into subgroups according to their maintenance treatment assignment (active drug or drug free) and treatment outcome (completing in remission or having a recurrence). Imipramine caused an increase in the GH ratio in all subgroups. Protocol completers had a significantly larger imipramine-induced increase in the GH ratio than did recurrers. The difference in time of GH secretion relative to sleep onset was found to correlate with treatment outcome and was independent of medication status during maintenance.