Sex differences in thyroid axis function: Relevance to affective disorder and its treatment

Bidirectional negative relationship between thyrotropin and kidney function during alcohol intoxication in males

Introduction

Despite a well-established direct toxic effect of alcohol on renal cells, there is a salutary dose-dependent effect of alcohol consumption on common laboratory parameters related to kidney performance. Alcohol also impacts thyroid hormones, while thyroid status modulates kidney function. The modulation of kidney parameters with thyrotropin (TSH) and thyroid status indicates a possible interaction between alcohol, kidney, and thyroid functions. This retrospective study was conducted to test the hypothesis that the positive effect of alcohol use on the estimated glomerular filtration rate (eGFR) is mediated by alcohol's effect on thyroid hormones.

Methods

We reviewed the electronic medical records of 767 hospitalized adult patients free of thyroid disorders who received medical care in the Mayo Clinic Health System from June 2019 through June 2022 and had blood alcohol concentration (BAC), serum TSH, and serum creatinine measured during the hospitalization. We calculated the eGFR using both the re-expressed Modification of Diet in Renal Disease (MDRD II) study equation and the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) Creatinine equation.

Results

We found a significant relationship of BAC with eGFR (CKD-EPI) and TSH in males only. BAC had a positive association with eGFR (b = 0.24, p = 0.0001) and negative with TSH (b=-0.17, p = 0.006). The covariance between the two outcomes (eGFR and TSH) was negative (b = -0.12, p = 0.049). The path analyses using the eGFR MDRD II equation were not significant in males, whereas females had no significant path analyses with either of the eGFR equations.

Discussion

We observed that BAC influences both eGFR and TSH, whereas eGFR and TSH influence each other. After considering important covariates (e.g., age, body mass index, diabetes mellitus, cardiovascular disease, chronic kidney disease, and chronic liver disease) and the negative bidirectional effect of TSH and eGFR, a positive impact of BAC on eGFR was observed in males.

Patterns of Thyroid Hormone Prescription in Patients with Bipolar or Schizoaffective Disorder: Findings from the LiSIE Retrospective Cohort Study

The prescription of thyroid hormone replacement therapy (THRT) has increased in the general population; the thyroid stimulating hormone (TSH) threshold to initiate THRT has decreased. It remains unclear whether a similar trend has occurred in patients with bipolar disorder (BD). In this work we explore patterns and trends of prescribing THRT in patients with BD or schizoaffective disorder (SZD) with an observational study and time-trend analysis in the framework of the LiSIE (Lithium-Study into Effects and Side Effects) retrospective cohort study. In most patients, THRT was initiated for subclinical hypothyroidism. The median TSH at which THRT was started was 6.0 (IQR 4.0) mIU/L and the median free serum thyroxine (fT4) at which THRT was started was 11.8 (IQR 3.9) pmol/L. The median TSH concentration at the start of THRT decreased annually with 0.10 mIU/L (p = 0.047) and was higher in patients treated with lithium than in patients treated with other mood stabilisers (p = 0.02). In conclusion, THRT was typically initiated in the context of mild or absent alterations of thyroid function tests with a decreasing TSH threshold. As THRT is rarely reversed once initiated, clinicians need to weigh up potential benefits and risks when prescribing THRT for subclinical hypothyroidism in patients with BD or SZD.

Prevalence of goiter among children in Ethiopia and associated factors: a systematic review and meta-analysis

BACKGROUND

The distribution of goiter among children and its risk factors are not well investigated in Ethiopia. Therefore, this systematic review and meta-analysis was designed to determine the pooled prevalence of goiter and its associated factors among children in Ethiopia.

METHODS

Electronic web-based searches of PubMed, Google Scholar, EMBASE, and the World Health Organization's Hinari portal (which includes the SCOPUS, African Index Medicus, and African Journals Online databases) were conducted to find primary studies. Relevant data were extracted and descriptive summaries of the studies were presented in tables. The I2 statistic was used to assess heterogeneity across studies. Funnel plot asymmetry and Egger's tests were used to check for publication bias. A random effects model was used to estimate the pooled prevalence of goiter. Odds ratios (OR) with 95% Confidence Intervals (CI) were also used to determine the association of identified variables with goiter. All statistical analyses were conducted using Stata version 14 software.

RESULTS

Our search identified 982 studies, of which, 19 articles were eligible for inclusion in the final meta-analysis. The pooled estimate of goiter among children in Ethiopia was 40.50% (95% CI: 33.6-47.40). The regional distribution of goiter ranged from 44.22 (95% CI: 17.44-71) in Southern Nations Nationalities and Peoples' Region, to 32.79% (95% CI: 19.86-45.73) in Benishangul Gumez region. The prevalence of goiter among female children (44.34%) was higher than among male (32.88%) children. Goiter prevalence was also significantly higher among children who consumed vegetables three or more times per week OR = 1.3 (95% CI: 1.02-1.66); those who had family history of goiter, OR = 2.38 (95% CI: 1.9-2.99); and those whose family stored salt near to fires, OR = 1.4 l (95% CI: 1.1-1.79).

CONCLUSION

The prevalence of goiter among children in Ethiopia was high, and endemic according to the WHO criteria. Our findings suggest the need for interventions to improve salt iodization, and for improved health education on appropriate salt storage. In addition, more research may be needed to improve our understanding of foods that increase the risk of goiter among children.

Sex differences and the neurobiology of affective disorders

Observations of the disproportionate incidence of depression in women compared with men have long preceded the recent explosion of interest in sex differences. Nonetheless, the source and implications of this epidemiologic sex difference remain unclear, as does the practical significance of the multitude of sex differences that have been reported in brain structure and function. In this article, we attempt to provide a framework for thinking about how sex and reproductive hormones (particularly estradiol as an example) might contribute to affective illness. After briefly reviewing some observed sex differences in depression, we discuss how sex might alter brain function through hormonal effects (both organizational (programmed) and activational (acute)), sex chromosome effects, and the interaction of sex with the environment. We next review sex differences in the brain at the structural, cellular, and network levels. We then focus on how sex and reproductive hormones regulate systems implicated in the pathophysiology of depression, including neuroplasticity, genetic and neural networks, the stress axis, and immune function. Finally, we suggest several models that might explain a sex-dependent differential regulation of affect and susceptibility to affective illness. As a disclaimer, the studies cited in this review are not intended to be comprehensive but rather serve as examples of the multitude of levels at which sex and reproductive hormones regulate brain structure and function. As such and despite our current ignorance regarding both the ontogeny of affective illness and the impact of sex on that ontogeny, sex differences may provide a lens through which we may better view the mechanisms underlying affective regulation and dysfunction.

Adjunctive thyroid hormone treatment in rapid cycling bipolar disorder: A double-blind placebo-controlled trial of levothyroxine (L-T4 ) and triiodothyronine (T3 )

OBJECTIVES

This report describes the first comparative double-blind, placebo-controlled trial of levothyroxine (L-T₄ ) and triiodothyronine (T₃ ) as adjunctive treatments in rapid cycling bipolar disorder.

METHODS

Thirty-two treatment-resistant, rapid cycling patients who had failed a trial of lithium were randomized into three treatment arms: L-T₄ , T₃ , or placebo. They were followed for ≥4 months with weekly clinical and endocrine assessments.

RESULTS

There were no statistically significant differences between the groups in age, gender, duration of illness, or thyroid status. Markov chain analyses were employed to assess treatment effects on cycling patterns among mood states (euthymia, depression, mania, and mixed). Within groups, post-treatment the L-T₄ group spent significantly less time depressed or in a mixed state and greater time euthymic. The T₃ and placebo groups did not differ significantly pre- and post-treatment in any mood state, although the pattern of effects was the same for the T₃ group as for the L-T₄ group. Between groups, the L-T₄ group had a significantly greater increase in time euthymic and decrease in time in the mixed state than the placebo group. Other group differences were not significant, although they were in the expected direction.

CONCLUSIONS

The findings in this first double-blind study directly comparing the effects of L-T₄ and T₃ therapy against placebo provide evidence for the benefit of adjunctive L-T₄ in alleviating resistant depression, reducing time in mixed states and increasing time euthymic. Adjunctive T₃ did not show statistically significant evidence of benefit over placebo in reducing the time spent in disturbed mood states.

Gender differences in thyroid system function: relevance to bipolar disorder and its treatment

OBJECTIVES

Thyroid hormones play a critical role in the functioning of the adult brain, and thyroid diseases impair both mood and cognition. This paper reviews gender differences in thyroid system function that are relevant to the diagnosis and treatment of bipolar disorder.

METHODS

The study comprised a comprehensive literature review of gender differences in thyroid disease that are pertinent to mood disorders.

RESULTS

The prevalence of thyroid disease was found to be much higher in females than males, and to increase with age. The most commonly detected abnormality was subclinical hypothyroidism, which was found to occur in up to 20% of postmenopausal women. Females also had higher rates of thyroid autoimmunity. Individuals at risk for thyroid disease, such as adult females, may have had less ability to compensate for additional challenges to thyroid metabolism, including lithium treatment. Thyroid abnormalities were associated with a poorer response to standard treatments for mood disorders. Females with treatment-resistant mood disorders may have responded better than males to adjunctive therapy with thyroid hormones.

CONCLUSIONS

Disturbances of thyroid system function, which occur commonly in females, may complicate the diagnosis and treatment of mood disorders. In particular, this is clinically relevant during lithium treatment because lithium may impair vital thyroid metabolic pathways secondary to its anti-thyroid activity.

Gonadal steroids, brain, and behavior: role of context

The nature and extent of the impact of gender and reproductive function on mood has been the subject of speculation and controversy for centuries. Over the past 50 years, however, it has become increasingly clear that not only is the brain a major target of reproductive steroid hormones, but additionally, the steroid hormones, as neuroregulators, create a context thai influences a broad range of brain activities; ie, neural actions and resultant behaviors are markedly different in the presence and absence of gonadal steroids. In turn, the actions of gonadal steroids are themselves context-dependent. Thus, even where it can be demonstrated thai gonadal steroids trigger mood disorders, the triggers are normal levels of gonadal steroids (to be contrasted with the mood disturbances accompanying endocrinopathies), and the mood disorders appear only in a subset of susceptible individuals. The context specificity and differential susceptibility to affective dysregulation seen in women with reproductive endocrine-related mood disorders are undoubtedly important underlying characteristics of a wide range of psychiatric disorders in which the triggers have not yet been identified. Consequently, reproductive endocrine-related mood disorders offer unparalleled promise for the identification of those contextual variables that permit biological stimuli to differentially translate into depression in individuals at risk.

Therapeutic armamentarium for treating depression

Depressive disorders are highly prevalent and are a leading cause of disability, morbidity, and mortality worldwide; however, they often remain undertreated or untreated. This article provides a broad overview of the many strategies for treating depression. More than 24 antidepressant medications and depression-focused psychotherapies are available as first-choice options for treating depression. When patients have not had a satisfactory treatment response, the 2 main strategies are switching to an alternative antidepressant therapy or adding a second antidepressant therapy. A large number of medication combinations have been reported in the literature, and some have been shown to be effective in controlled studies. Nonstandard alternatives to conventional antidepressant treatments include exercise, light therapy, sleep deprivation, and various complementary and alternative therapies. For more chronic and refractory forms of depression, various neuromodulation therapies are available or are being investigated. Because depressive disorders are common in primary care and other medical settings, medical practitioners should be aware of the therapeutic armamentarium available for treating depression.

Effects of various antidepressants on serum thyroid hormone levels in patients with major depressive disorder

A total of 62 patients with major depressive disorder were analyzed in the study. Patients were evaluated for 11 weeks in an open label design to investigate the differential effects of reboxetine, sertraline and venlafaxine on thyroid hormones. Serum thyrotrophin (TSH), thyroxine (T4) and free (f)T4 levels were measured before and after treatment. All groups showed significant improvement in HAM-D scores. TSH level significantly reduced and T4 level significantly increased in the reboxetine group, however TSH level significantly increased and T4 level significantly reduced in the sertraline group. Percent changes of TSH (p=0.007) and T4 (p=0.001) were significantly different between the reboxetine and sertraline groups. In the sertraline group, baseline TSH levels were correlated with response to treatment as determined by the change in HAM-D scores (p=0.03, r=0.648). There was a significant association between the percent changes in TSH values and the reduction in HAM-D scores in the reboxetine group (p=0.03, r=-0.434). In the whole study group, female patients had lower values of basal T4 compared with men (p=0.043), however percent changes of T4 did not differ between genders. In the treatment-responders significant increase in the reboxetine group and significant decrease in the sertraline group regarding the T4 values were found. We observed that various antidepressants had different effects on thyroid hormone levels and this could be attributed to the different mechanisms of actions of these antidepressants.

Supraphysiological doses of levothyroxine alter regional cerebral metabolism and improve mood in bipolar depression

Supplementation of standard treatment with high-dose levothyroxine (L-T(4)) is a novel approach for treatment-refractory bipolar disorders. This study tested for effects on brain function associated with mood alterations in bipolar depressed patients receiving high-dose L-T(4) treatment adjunctive to ongoing medication (antidepressants and mood stabilizers). Regional activity and whole-brain analyses were assessed with positron emission tomography and [(18)F]fluorodeoxyglucose in 10 euthyroid depressed women with bipolar disorder, before and after 7 weeks of open-label adjunctive treatment with supraphysiological doses of L-T(4) (mean dose 320 microg/day). Corresponding measurements were acquired in an age-matched comparison group of 10 healthy women without L-T(4) treatment. The primary biological measures were relative regional activity (with relative brain radioactivity taken as a surrogate index of glucose metabolism) in preselected brain regions and neuroendocrine markers of thyroid function. Treatment-associated changes in regional activity (relative to global activity) were tested against clinical response. Before L-T(4) treatment, the patients exhibited significantly higher activity in the right subgenual cingulate cortex, left thalamus, medial temporal lobe (right amygdala, right hippocampus), right ventral striatum, and cerebellar vermis; and had lower relative activity in the middle frontal gyri bilaterally. Significant behavioral and cerebral metabolic effects accompanied changes in thyroid hormone status. L-T(4) improved mood (remission in seven patients; partial response in three); and decreased relative activity in the right subgenual cingulate cortex, left thalamus, right amygdala, right hippocampus, right dorsal and ventral striatum, and cerebellar vermis. The decrease in relative activity of the left thalamus, left amygdala, left hippocampus, and left ventral striatum was significantly correlated with reduction in depression scores. Results of the whole-brain analyses were generally consistent with the volume of interest results. We conclude that bipolar depressed patients have abnormal function in prefrontal and limbic brain areas. L-T(4) may improve mood by affecting circuits involving these areas, which have been previously implicated in affective disorders.

Sex-specific self-reported mood changes by patients with bipolar disorder

INTRODUCTION

While the prevalence of bipolar disorder I is similar between men and women, the clinical course may differ. This study investigated if there are differences in the clinical presentation of bipolar disorder between the sexes.

METHODS

Mood patterns were documented using ChronoRecord software for self-reporting. Patients entered mood, medications, sleep, life events and menstrual data daily acquired over the period of three months. 8662 Days of data were received from 80 patients: 3483 days from 35 men and 5179 days from 45 women.

RESULTS

The distribution of the time spent in mood categories differed between men and women (P<0.001). Men were depressed 17.0% of the time, euthymic 74.0% of the time and manic 5.6% of the time. Women were depressed 28.3% of the time, euthymic 64.2% of the time and manic 7.5% of the time. Over 80% of all reported symptoms for both sexes were mild. Women exhibited large mood fluctuations (greater than 10 in either direction on a 100-unit scale) more frequently than men. Most of the reproductive aged women (55%) reported significant mood changes across the menstrual cycle.

CONCLUSIONS

The clinical course of bipolar disorder differed between the sexes. Women reported depression and large fluctuations in mood more frequently than men. Women also experienced mood changes across the menstrual cycle.

Thyroid indices and response to fluoxetine and nortriptyline in major depression

We investigated: (i) the status of thyroid hormones and their clinical correlates in patients with major depression; (ii) changes in thyroid hormone status after treatment with fluoxetine versus nortriptyline; and (iii) whether blunted thyrotropin-stimulating hormone (TSH) response to thyrotropin-releasing hormone (TRH) challenge predicts improvement after 6 weeks of fluoxetine versus nortriptyline treatment. Patients with major depression entering a treatment trial were assessed with the Structured Clinical Interview for DSM-III-R and were rated on the Montgomery-Asberg Depression Rating Scale (MADRS). Blood samples were taken for TSH, thyroxine (T4) and free thyroxine (FT4) measurement, and the maximum TSH response (deltamaxTSH) to a TRH challenge test was undertaken. Patients were then randomly assigned to receive fluoxetine or nortriptyline for six weeks. At 6 weeks, patients repeated the thyroid hormone assessment and completed the MADRS. Mean concentrations of TSH, T4, FT4 and deltamaxTSH were within reference ranges. T4 and FT4 levels decreased significantly after treatment in responders, but not in nonresponders. After treatment, deltamaxTSH concentrations decreased significantly in patients who responded to fluoxetine, and increased in patients who responded to nortriptyline. Patients with deltamaxTSH blunting at pretreatment were more likely to be male, to have higher MADRS scores and have a history of alcohol and drug dependence. Patients with a pretreatment deltamaxTSH of < 3.0 microm/ml showed greater improvement on the MADRS when treated with fluoxetine than if treated with nortriptyline. We observed a decrease in T4 and FT4 in responders to treatment with fluoxetine or nortriptyline. Positive relationships between deltamaxTSH blunting and alcohol and drug abuse and severity of depression were found. Patients with blunted deltamaxTSH responded better to fluoxetine than to nortriptyline. It is suggested that a blunted DmaxTSH may reflect a predominantly serotonergic disturbance in this group of patients with major depression.

Medical differentials with potential behavioral manifestations

Boundaries between behavioral conditions and medical differentials are likely to blur more rather than less as we learn more about genomic, cellular, and subcellular effects on common conditions. These changes should lead to better treatment but may also require a paradigm shift in how we view behavioral conditions and the mechanisms that contribute to them.

Gender differences in depression. Critical review

BACKGROUND

With few exceptions, the prevalence, incidence and morbidity risk of depressive disorders are higher in females than in males, beginning at mid-puberty and persisting through adult life.

AIMS

To review putative risk factors leading to gender differences in depressive disorders.

METHOD

A critical review of the literature, dealing separately with artefactual and genuine determinants of gender differences in depressive disorders.

RESULTS

Although artefactual determinants may enhance a female preponderance to some extent, gender differences in depressive disorders are genuine. At present, adverse experiences in childhood, depression and anxiety disorders in childhood and adolescence, sociocultural roles with related adverse experiences, and psychological attributes related to vulnerability to life events and coping skills are likely to be involved. Genetic and biological factors and poor social support, however, have few or no effects in the emergence of gender differences.

CONCLUSIONS

Determinants of gender differences in depressive disorders are far from being established and their combination into integrated aetiological models continues to be lacking.

Psychoneuroendocrinology of mood disorders. The hypothalamic-pituitary-thyroid axis

Abnormal thyroid functioning can affect mood and influence the course of unipolar and bipolar disorder. Even mild thyroid dysfunction has been associated with changes in mood and cognitive functioning. Thyroid hormone supplementation may have role in the treatment of certain mood disorders, particularly rapid-cycling bipolar disorder. Women are more vulnerable to thyroid dysfunction than men and also respond better to thyroid augmentation. This article reviews the relationship between thyroid function and mood, and the use of thyroid hormones in the treatment of mood disorders. The impact of gender on these issues is also discussed.

Differences in thyroid function between bipolar manic and mixed states

BACKGROUND

High rates of thyroid axis abnormalities have been reported in most studies of patients with rapid-cycling bipolar disorder. Mixed states share similarities with rapid-cycling, including close temporal occurrence of manic and depressive symptoms, predominance in women, poor outcome, and less robust response to lithium compared with pure mania; however, thyroid axis abnormalities have not been well studied in mixed mania.

METHODS

To test the hypothesis that mixed states are associated with a higher prevalence of hypothyroidism than pure mania, immunoreactive triiodothyronine (T3), thyroxine (T4), and thyroid-stimulating hormone (TSH) concentrations were determined from serum obtained at the time of admission in 37 consecutive patients with DSM-III-R bipolar disorder, manic or mixed.

RESULTS

The mean TSH concentration was significantly higher, and the mean T4 concentration was significantly lower in patients with mixed mania compared with pure mania. There were no significant differences in T3 concentration or in previous lithium exposure.

CONCLUSIONS

These findings suggest thyroid axis dysfunction is more common in bipolar mixed than in bipolar manic patients.

Novel uses of thyroid hormones in patients with affective disorders

Hormones of the thyroid axis have been used to treat patients with any of several mental illnesses. However, in recent decades interest has focused almost exclusively on depression, though thyroid hormones, mainly thyroxine (T4), are used with lithium in rapid cycling bipolar disorder, a condition in which depression and mania rapidly alternate. In depression L-triiodothyronine (T3) has been used in preference to T4 because of its rapid onset and offset of action. In women starting treatment, T3 hastens the onset of therapeutic action of standard antidepressant drugs. It fails to do so in depressed men, who anyway respond faster than women to standard antidepressants. Standard drugs fail to produce satisfactory improvement in one-quarter to one-third of depressed patients. Then, in both men and women, T3 converts about two-thirds of drug failures to successes in rapid fashion. Lithium, which has antithyroid properties, produces a similar conversion rate. The majority of depressed patients are grossly euthyroid, but many show one or another subtle change in thyroid axis activity. However, the thyroid state of patients has not been matched systematically with their response to thyroid hormone augmentation. It seems likely that a tendency toward hypothyroidism can predispose to depression, but when depression occurs in a euthyroid patient, the thyroid axis is often invoked in the process of restitution.