Effect of antidepressant medication on morning and evening thyroid function tests during a major depressive episode

Postpartum depression in rats causes poor maternal care and neurochemical alterations on dams and long-lasting impairment in sociability on the offspring

Postpartum depression is a mentally disabling disease with multifactorial etiology that affects women worldwide. It can also influence child development and lead to behavioral and cognitive alterations. Despite the high prevalence, the disease is underdiagnosed and poorly studied. To study the postpartum depression caused by maternal separation model in rats, dams were separated from their litter for 3 h daily starting from lactating day (LD) 2 through LD12. Maternal studies were conducted from LD5 to LD21 and the offspring studies from postnatal day (PND) 2 through PND90. The stress caused by the dam-offspring separation led to poor maternal care and a transient increase in anxiety in the offspring detected during infancy. The female offspring also exhibited a permanent impairment in sociability during adult life. These changes were associated with neurochemical alterations in the prefrontal cortex and hippocampus, and low TSH concentrations in the dams, and in the hypothalamus, hippocampus and striatum of the offspring. These results indicate that the postpartum depression resulted in a depressive phenotype, changes in the brain neurochemistry and in thyroid economy that remained until the end of lactation. Changes observed in the offspring were long-lasting and resemble what is observed in children of depressant mothers.

Thyroid axis activity and dopamine function in depression

BACKGROUND

Several lines of evidence suggest alterations in both hypothalamic-pituitary-thyroid (HPT) axis and dopamine (DA) function in depressed patients. However, the functional relationships between HPT and DA systems have not been well defined.

METHODS

We examined thyrotropin (TSH) response to 0800 h and 2300 h protirelin (TRH) challenges, and adrenocorticotropic hormone (ACTH), cortisol and growth hormone (GH) responses to apomorphine (APO, a DA receptor agonist), in 58 drug-free DSM-IV major depressed inpatients without a suicidal behavior, and 22 healthy hospitalized controls.

RESULTS

Compared with controls, patients showed 1) lower basal serum 2300 h-TSH, 2300 h-∆TSH, and ∆∆TSH (difference between 2300 h-∆TSH and 0800 h-∆TSH) levels, and 2) lower cortisol response to APO (∆COR). A negative relationship between ∆∆TSH values and hormonal responses to APO was observed in the depressed group, but not in the control group. When patients were classified on the basis of their ∆∆TSH status, patients with reduced ∆∆TSH values (< 2.5 mU/L) showed hormonal APO responses comparable to those of controls. Patients with normal ∆∆TSH values exhibited lower ∆ACTH, ∆COR, and ∆GH values than patients with reduced ∆∆TSH values and controls.

CONCLUSION

Taken together, these results suggest that hypothalamic DA function is unaltered in depressed patients with HPT dysregulation (i.e., increased hypothalamic TRH drive leading to altered TRH receptor chronesthesy on pituitary thyrotrophs). Conversely, hypothalamic DA-receptor function is decreased in patients with normal HPT axis activity. These findings are discussed in the context of the role of TRH as a homeostatic neuromodulator in depression.

Influence and interaction of genetic, cognitive, neuroendocrine and personalistic markers to antidepressant response in Chinese patients with major depression

OBJECTIVE

Despite there is a wide range of antidepressants available, with various mechanisms of actions, the efficacy of current therapeutic options is yet satisfactory. Previous shreds of evidence have indicated that genetics, cognitive, neuroendocrine, as well as personality factors, are all intrinsically linked and contribute to the diversity of treatment outcomes. We, therefore, sought to investigate this hypothesis in this study.

METHOD

Based on 610 samples treated with a selection of serotonin reuptake inhibitor (SSRI), serotonin-norepinephrine reuptake inhibitors (SNRI), noradrenergic and specific serotonergic antidepressant (NaSSA) or tricyclic antidepressant (TCA), we compared the therapeutic effects of these four classes of drugs by survival analyses. Pharmacogenomic and survival analyses were carried out to explore the hereditary factors for curative effect and the accumulation of genetic factors was further discussed through pathway analysis and the global test. We built a machine learning-based prediction model that integrates genetic and non-genetic factors (including cognition, endocrinology, personality intelligence) to distinguish drug efficacy in single class drug situations. The values of the non-genetic makers after 6 weeks' treatment were collected to evaluate the efficacy of the model.

RESULTS

Our results from the 6-week antidepressant therapeutic study indicated that SSRI and SNRI are better treatments than those of TCA and NaSSA in the Chinese population. Among all possible paired single-agent survival analyses, citalopram and venlafaxine were more effective than mirtazapine. Allele C carriers at rs6354 (SLC6A4) and allele G carriers at rs12150214 (SLC6A4) were significantly prone to poorer treatment response to fluoxetine. Besides, the combination of three loci (rs929377-rs6191-rs32897) located in HPA pathway was significantly associated with the treatment outcome of fluoxetine. In female MDD patients, the minor allele of rs6323 and rs1137070 on the MAOA gene likely lead to a worse response to venlafaxine. Furthermore, genetic variants linked to drug efficacy tended to concentrate on the neurotrophin pathway in depressed patients comorbid with anxiety. From multivariate models, more severe cognitive deficits, psychopathic personality and lower levels of operational intelligence, and higher levels of cortisol predicted worse response status with SSRI or SNRI after 6-week treatment. Notably, genetic factors in the multi-dimensional prediction model for both classes of drugs include loci in HTR2A and CRHBP genes.

CONCLUSION

SSRI and SNRI are more suitable for the treatment of Chinese people with depression. SLC6A4 genetic variants, as well as HPA pathway, play an important role in the fluoxetine antidepressant therapeutic response while the polymorphism of MAOA gene involved in the pharmacological action of venlafaxine among female MDD patients. The presence of anxiety in MDD patients was related to the neurotrophin pathway. Genetic, cognitive, neuroendocrine, and personality intelligence factors combined have an ensemble impact on the medication effect of patients with major depression, leading to more precise and personalized medicine for specific groups of people.

Are the thyroid and adrenal system alterations linked in depression?

BACKGROUND

Disturbances in the hypothalamic-pituitary-thyroid (HPT) and hypothalamic-pituitary-adrenal (HPA) axes have been frequently found in major depression. Given that glucocorticoids may inhibit thyrotropin (TSH) and thyrotropin-releasing hormone (TRH) secretion, it has been hypothesized that hypercortisolemia could lead to HPT axis abnormalities. So far, data on interactions between the HPA and HPT axes in depression remain inconclusive.

METHODS

In order to investigate this issue, we examined circadian rhythms of serum TSH and cortisol (sampled at 4 -hly intervals throughout a 24 -h span), TSH responses to 0800 h and 2300 h protirelin (TRH) tests and cortisol response to dexamethasone suppression test (DST) in 145 unmedicated inpatients meeting DSM-IV criteria for major depressive disorder (MDDs) and 25 healthy hospitalized control subjects (HCs).

RESULTS

The secretion of TSH and cortisol exhibited a significant circadian rhythm both in HCs and MDDs. However, compared to HCs, MDDs showed: 1) reduced TSH mesor and amplitude values; 2) blunted 2300 h-ΔTSH and ΔΔTSH values (i.e. differences between 2300 h and 0800 h TRH-TSH responses); and 3) increased cortisol mesor and post-DST cortisol values. DST nonsuppresssors (n = 40, 27 %) showed higher cortisol mesor than DST suppressors (n = 105, 73 %). There was no difference between DST suppressors and nonsuppressors in their TSH circadian parameters and TRH-TSH responses. In addition, cortisol values (circadian and post-DST) were not related to TRH test responses.

CONCLUSION

Our results do not confirm a key role for hypercortisolemia in the HPT axis dysregulation in depression.

Relationship between chronobiological thyrotropin and prolactin responses to protirelin (TRH) and suicidal behavior in depressed patients

BACKGROUND

So far, investigations of the relationships between suicidality and the activity of the thyrotropic and lactotropic axes are scarce and have yielded conflicting results.

METHODS

We studied the thyrotropin (TSH) and prolactin (PRL) responses to 0800h and 2300h protirelin (TRH) stimulation tests, carried out on the same day, in 122 euthyroid DSM-5 major depressed inpatients with suicidal behavior disorder (SBD) (either current [n=71], or in early remission [n=51]); and 50 healthy hospitalized controls.

RESULTS

Baseline TSH and PRL measurements did not differ across the 3 groups. In SBDs in early remission, the TSH and PRL responses to TRH tests (expressed as the maximum increment above baseline value after TRH [Δ]) were indistinguishable from controls. Current SBDs showed (1) lower 2300h-ΔTSH and lower ΔΔTSH values (differences between 2300h-ΔTSH and 0800h-ΔTSH) than controls and SBDs in early remission; and (2) lower baseline free thyroxine (FT_4B) levels than controls. In the current SBD group, ΔΔPRL values (differences between 2300h-ΔPRL and 0800h-ΔPRL) were correlated negatively with lethality. Moreover, in current SBDs (1) violent suicide attempters (n=15) showed lower FT_4B levels, lower TSH-TRH responses (both at 0800h and 2300h), and lower ΔΔTSH and ΔΔPRL values than controls, while (2) non-violent suicide attempters (n=56) showed lower ΔΔTSH values than controls and higher TSH-TRH responses (both at 0800h and 2300h) than violent suicide attempters.

CONCLUSIONS

Our results suggest that central TRH secretion is not altered in depressed patients with SBD in early remission. The findings that current SBDs exhibit both decreased FT_4B levels and decreased evening TSH responses (and consequently, decreased ΔΔTSH values) support the hypothesis that hypothalamic TRH drive is reduced-leading to an impaired TSH resynthesis in the pituitary during the day after the morning TRH challenge. In violent suicide attempters, the marked abnormalities of TRH test responses might indicate a greatest reduction in hypothalamic TRH drive. These results further strengthen the possibility that a deficit in central TRH function may play a key role in the pathogenesis of suicidal behavior.

Effect of Mirtazapine on Thyroid Hormones in Adult Patients with Major Depression

Hypothalamic pituitary thyroid (HPT) axis abnormalities and alterations in major depression are reported in literature. The aim of our study was to evaluate the effect of mirtazapine on thyroid hormones after 6 months of therapy in a sample of adult outpatients with Major Depression (MD). 17 adult outpatients (7 men, 10 women) with MD according to DSM-IV criteria, were included in the study. All participants had to have met criteria for a major depressive episode with a score of at least 15 on the Hamilton Depression Rating Scale (HAM-D). Fasting venous blood samples were obtained for determination of serum Thyroid Stimulating Hrmone (TSH), Free T3 (FT3) and Free T4 (FT4) concentrations both at baseline and after 6 months of therapy. HAM-D scores decreased significantly from the first day of treatment to the end of the treatment period (p<0.001) and twelve patients (70.6%) were classified as responders. A significant increase in FT3 concentrations was found between baseline and the end of treatment period (P=0.015) whereas FT4 concentrations decreased (P=0.046). No significant changes were found in TSH levels. Higher FT4 concentrations at baseline predicted higher HAM-D scorers both at baseline and at the end of the treatment period. Furthermore, higher FT3 concentrations at endpoint were found to be predictors of lower HAM-D scores. Long-term treatment with mirtazapine increases FT3 levels and decreases FT4 maybe involving the deiodination process of T4 into T3.

Chronobiological hypothalamic-pituitary-thyroid axis status and antidepressant outcome in major depression

BACKGROUND

We previously demonstrated that the difference between 2300h and 0800h TSH response to protirelin (TRH) tests on the same day (ΔΔTSH test) is an improved measure in detecting hypothalamic-pituitary-thyroid (HPT) axis dysregulation in depression. This chronobiological index (1) is reduced in about three quarters of major depressed inpatients, and (2) is normalized after successful antidepressant treatment. In the present study, we examined whether early changes in HPT axis activity during the first 2 weeks of antidepressant treatment could be associated with subsequent outcome.

METHODS

The ΔΔTSH test was performed in 50 drug-free DSM-IV euthyroid major depressed inpatients and 50 hospitalized controls. After 2 weeks of antidepressant treatment the ΔΔTSH test was repeated in all inpatients. Antidepressant response was evaluated after 6 weeks of treatment.

RESULTS

At baseline, ΔΔTSH values were significantly lower in patients compared to controls and 38 patients (76%) showed reduced ΔΔTSH values (i.e., <2.5mU/L). After 2 weeks of antidepressant treatment, 20 patients showed ΔΔTSH normalization (among them 18 were subsequent remitters), while 18 patients did not normalize their ΔΔTSH (among them 15 were non-remitters) (p<0.00001). Among the 12 patients who had normal ΔΔTSH values at baseline, 8 out 9 who had still normal values after 2 weeks of treatment were remitters, while the 3 with worsening HPT axis function (i.e., reduced ΔΔTSH value after 2 weeks of treatment) were non-remitters (p<0.02). A logistic regression analysis revealed that ΔΔTSH levels after 2 weeks of treatment could predict the probability of remission (odds ratio [OR]=2.11, 95% confidence interval [CI]=1.31-3.41).

CONCLUSIONS

Our results suggest that after 2 weeks of antidepressant treatment: (1) chronobiological restoration of the HPT axis activity precedes clinical remission, and (2) alteration of the HPT axis is associated with treatment resistance.

Risk assessment and predicting outcomes in patients with depressive symptoms: a review of potential role of peripheral blood based biomarkers

Depression is one of the major global health challenges and a leading contributor of health related disability and costs. Depression is a heterogeneous disorder and current methods for assessing its severity in clinical practice rely on symptom count, however this approach is unreliable and inconsistent. The clinical evaluation of depressive symptoms is particularly challenging in primary care, where the majority of patients with depression are managed, due to the presence of co-morbidities. Current methods for risk assessment of depression do not accurately predict treatment response or clinical outcomes. Several biological pathways have been implicated in the pathophysiology of depression; however, accurate and predictive biomarkers remain elusive. We conducted a systematic review of the published evidence supporting the use of peripheral biomarkers to predict outcomes in depression, using Medline and Embase. Peripheral biomarkers in depression were found to be statistically significant predictors of mental health outcomes such as treatment response, poor outcome and symptom remission; and physical health outcomes such as increased incidence of cardiovascular events and deaths, and all-cause mortality. However, the available evidence has multiple methodological limitations which must be overcome to make any real clinical progress. Despite extensive research on the relationship of depression with peripheral biomarkers, its translational application in practice remains uncertain. In future, peripheral biomarkers identified with novel techniques and combining multiple biomarkers may have a potential role in depression risk assessment but further research is needed in this area.

What future for neuroendocrinology in psychiatry?

In psychiatry, neuroendocrine techniques were initially considered a potential "window into the brain" by indirectly marking central nervous system limbic dysfunction. At present this conception has evolved, owing to significant progress over the last decades demonstrating direct involvement of neuropeptides and neurohormones in psychiatric diseases. In a synchronic perspective, neuroendocrine investigations evaluate a functional status at a given moment in the evolution of the disease, which results from both etiopathogenic processes and compensatory homeostatic mechanisms. These vital physiological changes appear to be potential targets for novel hormonally based pharmacotherapies. However, in the past few years, the interest for the study of neuroendocrine dysregulations in psychiatric patients has declined. In order to better understand this relative disinterest, this article will attempt to shed light on strengths and limitations of the neuroendocrine approaches in psychiatry. It is necessary to bear in mind that the usefulness of these techniques in the clinical, pathophysiological and therapeutic fields depends largely on the selectivity of stimuli and the appropriateness of the methodologies used. Owing to the complexity of the clinical phenomena, multifactorial approaches (combining several neuroendocrine challenge tests to imaging, immunological, neurophysiological, neurochemical and/or genetic techniques) are to be privileged in psychiatric investigations. Despite the inherent limitations of these approaches, due to their technical and ethical constraints, the neuroendocrine strategy can inform modern clinical practice and lead to new breakthroughs in future science and practice.

Prolactin and thyroid hormone levels are associated with suicide attempts in psychiatric patients

The aim of this study is to evaluate biological factors associated with recent suicidal attempts in a naturalistic sample. A total of 439 patients suffering from major depression disorder (MDD), bipolar disorder (BD) and psychotic disorders (schizophrenia, schizoaffective disorder and psychosis not otherwise specified), who were consecutively assessed in the Emergency Department of an Italian Hospital (January 2008-December 2009), were included. In the whole sample, suicide attempters and non-attempters differed with regard to free triiodothyronine (FT3) and prolactin values only. A univariate general linear model indicated significant effects of sex (F(1;379)=9.29; P=0.002), suicidal status (F(1;379)=4.49; P=0.04) and the interaction between sex and suicidal status (F(1;379)=5.17; P=0.02) on prolactin levels. A multinomial logistic regression model indicated that suicidal attempters were 2.27 times (odds ratio (OR)=0.44; 95% confidence interval (95%CI): 0.23/0.82; P=0.01) less likely to have higher FT3 values than non-attempters; while prolactin values failed to reach statistical significance (OR=0.99; 95%CI: 0.98/1.00; P=0.051). Both prolactin and thyroid hormones may be involved in a complex compensatory mechanism to correct reduced central serotonin activity. Further studies may help in understanding how these findings can be used by clinicians in assessing suicide risk.

Interaction between the serotonergic system and HPA and HPT axes in patients with major depression: implications for pathogenesis of suicidal behavior

Disturbances in the serotonin (5-hydroxytryptamine, 5-HT) system constitute the neurobiological abnormality most consistently associated with suicide. This abnormality could be a marker of vulnerability predisposing individuals to auto-aggressive and impulsive behavior. However, other abnormalities, such as hyperactivity of the hypothalamic-pituitary-adrenal (HPA) axis, have also been described in suicide victims. While inhibitory effects of adrenocorticosteroids on 5-HT_1A receptor function have been shown in animals, HPA axis hyperactivity does not seem to be responsible for the reduced 5-HT activity found in depressed patients with a history of suicidal behavior. On the other hand, hypothalamic-pituitarythyroid (HPT) axis dysfunction, frequently observed in depression, may represent a compensatory response to reduced central 5-HT neurotransmission. Moreover, in depressed patients with a history of suicidal behavior, the absence of a functional link between HPT and dopamine activity at the hypothalamic level may be implicated in the pathophysiology of suicidal behavior. Future research is needed to determine why compensatory mechanisms are not efficient in patients with suicidal behavior.

Thyroid autoimmunity and treatment response to escitalopram in major depression

BACKGROUND

There is evidence that immune alterations play an important part in the pathogenesis of major depression. Thyroid autoimmunity has been found in association with major depression in several studies.

AIM

1) to examine whether the prevalence of anti-thyroid peroxidase autoantibodies (anti-TPO) in depressive patients differs from that in healthy controls; 2) to investigate the possible relationship between thyroid autoimmunity, total T3, free T3, free T4, thyroid-stimulating hormone (TSH), clinical status and treatment outcome in depression.

METHOD

The study group consisted of 129 outpatients (69.8% female; mean age 31.7+/-12.0 years) with major depressive disorder with a Montgomery-Azsberg Depression Rating Scale total score of 22 or higher and 72 healthy controls (62.5% female; mean age 31.7+/-13.1 years). The patients were treated with escitalopram 10-20 mg/day for 12 weeks using open-label placebo non-controlled design. Anti-TPO, total T3, free T3, free T4 and TSH were measured before the treatment.

RESULTS

The anti-TPO was found in eight (8.9%) depressive and two (4.8%) healthy females without statistical difference between these groups. Since anti-TPO was not seen in males, all further statistical analyses were carried out in females. At the end of week 12 of the treatment, 60 female patients (66.7%) were defined as responders and 30 depressive females (33.3%) showed insufficient response to treatment. Although there were no significant differences in the measurements between responders and non-responders, the last group showed a trend for a higher prevalence of anti-TPO compared with responders.

CONCLUSION

Thyroid autoimmunity might be a factor predicting treatment response to antidepressants in depressive patients.

Thyroid axis activity and suicidal behavior in depressed patients

The aim of this study was to investigate the relationship between suicidal behavior and hypothalamic-pituitary thyroid (HPT) axis activity in depressed patients. The serum levels of thyrotropin (TSH), free thyroxine (FT4), and free triiodothyronine (FT3) were evaluated before and after 0800 and 2300 h thyrotropin-releasing hormone (TRH) challenges, on the same day, in 95 medication-free DSM-IV euthyroid major depressed inpatients and 44 healthy hospitalized controls. Compared to controls: (1) patients with a positive suicide history (PSH; n=53) showed lower basal FT4 (at 0800 h: p<0.005; at 2300 h: p<0.03), but normal FT3 levels, while patients with a negative suicide history (NSH; n=42) showed normal FT4 and FT3 levels; (2) TSH responses to TRH (DeltaTSH) were blunted in NSHs (at 0800 h: p<0.03; at 2300 h: p<0.00001), but not in PSHs; (3) both NSHs and PSHs showed lower DeltaDeltaTSH values (differences between 2300 h-DeltaTSH and 0800 h-DeltaTSH) (p<0.000001 and p<0.003, respectively). Compared to NSHs, basal FT4 levels were reduced in PSHs (at 0800 h: p<0.002; at 2300h: p<0.006). HPT parameters were not significantly different between recent suicide attempters (n=32) and past suicide attempters (n=21). However, compared to controls, recent suicide attempters showed lower 2300 h-DeltaTSH (p<0.04) and DeltaDeltaTSH (p<0.002) values, and lower basal FT4 values (at 0800 h: p<0.006; at 2300 h: p<0.02). Our results, obtained in a large sample of depressed inpatients, indicate that various degrees of HPT axis dysregulation are associated with the history of suicide.

Relationship between TSH levels in the normal range and short-term duloxetine efficacy

BACKGROUND

Whereas studies have suggested an association between abnormal TSH serum levels on antidepressant efficacy in major depressive disorder (MDD), the impact of normal serum TSH levels on antidepressant efficacy is unknown. This study aimed to investigate whether TSH serum levels within the normal range predict short-term antidepressant efficacy.

METHODS

Pooled data from 7 randomized, double-blind, placebo-controlled, MDD clinical trials were analyzed to compare the efficacy of duloxetine depending on baseline serum TSH levels. Adult outpatients with MDD (DSM-IV criteria) received duloxetine (60-120 mg/day, n=1242) or placebo (n=827) for up to 9 weeks. Efficacy was measured based on the 17-item Hamilton Rating Scale for Depression total score change, response rate, remission rate and time to response. TSH serum levels were measured at baseline using Microparticle Enzyme Immunoassay technology. Only patients with a TSH serum level within the normal range were considered for the analysis.

RESULTS

The mean (SD) of baseline TSH serum levels was 1.55 (0.86) mIU/L (median: 1.35; interquartile range: [0.92-1.94]). No significant treatment-by-TSH quartile interaction was evidenced in change from baseline, response, nor remission, indicating that the magnitude of duloxetine's treatment effects did not differ significantly between TSH quartiles. No significant difference in time to response was evidenced between any of the quartiles.

LIMITATIONS

This analysis is a post-hoc analysis of pooled data.

CONCLUSION

In this analysis of pooled data, the overall response to duloxetine in MDD did not differ regarding baseline serum TSH levels when considering TSH within the normal range.

Changes in hypothalamic-pituitary-thyroid axis following successful treatment with low-frequency right prefrontal transcranial magnetic stimulation in treatment-resistant depression

Hypothalamic-pituitary-thyroid (HPT) axis abnormalities have been reported in some patients with major depression. To knowledge, however, the effects of low-frequency right prefrontal transcranial magnetic stimulation (TMS) on the HPT axis have not yet been elucidated. The goal of this study was to evaluate alterations in the HPT axis associated with the therapeutic efficacy of TMS treatments. Twenty patients with treatment-resistant depression received five 60-s 1-Hz trains over the right dorsolateral prefrontal cortex. Twelve treatment sessions were administered within a 3-week period (total pulses, 3600). Responders were defined as a > or =50% decrease in the Hamilton Depression Rating Scale (HDRS) score. Serum levels of thyroid-stimulating hormone (TSH), free triiodothyronine (fT3), and free thyroxine (fT4) were measured, respectively, at pre- and post-treatment. There were no significant changes in fT3 and fT4 levels measured at either pre- or post-treatment in either responders or nonresponders; however, TSH levels of responders elevated significantly after TMS treatments. In addition, there was a significant negative correlation between TSH levels at pretreatment and decrease (%) in the HDRS score. These findings suggest that the HPT axis is associated with antidepressant effects of low-frequency right prefrontal TMS, and indicate that lower TSH levels at pre-treatment are correlated with better therapeutic efficacy.

Basal thyrotropin and major depression: relation to clinical variables and treatment outcome

OBJECTIVE

There is a current argument in thyroidology about whether the normal range for basal thyrotropin (TSH) is too broad. Some groups suggest that a TSH of less than 2.5 mIU/L is a better cut-off for euthyroidism. Because major depression is associated with changes in thyroid hormone status and thyroid hormones may be an effective treatment for major depression, we examined whether TSH levels above or below 2.5 mIU/L were related to clinical variables or treatment outcome in euthyroid patients with major depression.

METHODS

Outpatients with major depression (n =166) were assigned to high-normal and low-normal TSH groups based on their basal TSH levels. The 2 groups were compared along clinical variables and treatment outcome.

RESULTS

The low-normal TSH group was significantly more depressed, as measured by Hamilton Depression Rating Scale scores, and had more anxiety symptoms and suicidal tendencies than the high-normal group. There was no difference in treatment response between the groups.

CONCLUSIONS

A comparison of low-normal and high-normal basal TSH groups with major depression revealed significant differences in severity and symptoms of depression but no difference in treatment outcome. These data are preliminary and require replication in a larger sample.

Efficacy and safety of triiodothyronine supplementation in patients with major depressive disorder treated with specific serotonin reuptake inhibitors

The thyroid hormone, triiodothyronine (T3), is used as a supplement to antidepressant treatment of major depression, to accelerate and enhance response and as an augmenter in patients who have not responded. While there is support from controlled trials and meta-analyses for the use of T3 in conjunction with tricyclic antidepressants, the evidence base for supplementation of specific serotonin reuptake inhibitors (SSRIs) with T3 is more limited. We reviewed the available literature on T3 supplementation of SSRIs including open-label studies and randomized controlled trials (RCTs). Five RCTs were identified. Three were enhancement studies in which T3 was administered concurrently with the antidepressant from the start of treatment and two were augmentation studies in which T3 was added to the antidepressant treatment of patients who had not responded. Three open augmentation studies were identified. The RCTs were too disparate in methodology to allow a meta-analysis to be performed. The enhancement studies are inconclusive in that one showed strongly positive effects of T3, one showed no effect and one showed a trend. The open augmentation studies supported an effect of T3 in SSRI non-responsive patients with some support from a large RCT; a smaller, underpowered RCT did not show efficacy. T3 was well tolerated in most of the studies and adverse effects do not seem to be an impediment to clinical use. Some of the studies identified clinical and thyroid function correlates of response that require further investigation. Further research is needed before it can be definitively established whether T3 is an effective supplement to SSRIs in patients with MDD. The appropriate timing of T3 supplementation needs to be explored and also the dose and length of treatment.

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.

Psychostimulants for depression

BACKGROUND

Depression is common, disabling, costly and under-treated. There are problems in the current first-line drug treatment, antidepressants, for moderate or severe depression. There is a body of research that has evaluated the effect of psychostimulants (PS) in the treatment of depression. This has not been reviewed systematically.

OBJECTIVES

To determine the effectiveness of PS in the treatment of depression and to assess adverse events associated with PS.

SEARCH STRATEGY

Databases CCDANCTR-Studies and CCDANCTR-References were searched on 21/6/2006. Cochrane Central Register of Controlled Trials, MEDLINE, EMBASE, PsycInfo, AMED, CINAHL, Dissertation Abstracts and the National Health Service Research Register were searched.

SELECTION CRITERIA

Randomised controlled trials (RCTs) assessing the effectiveness of PS were included. The trial population comprised adults of either sex with a diagnosis of depression.

DATA COLLECTION AND ANALYSIS

Two review authors extracted the data independently and assessed trial quality. Meta-analysis was considered for trials with comparable key characteristics. The primary outcome was depression symptoms, based on a continuous outcome, using the standardised mean difference (SMD), or a dichotomous measure of clinical response, using odds ratios (OR), with 95% confidence intervals (CI).

MAIN RESULTS

Twenty-four RCTs were identified. The overall quality of the trials was low. Five drugs were evaluated; dexamphetamine, methylphenidate, methylamphetamine, pemoline and modafinil. Modafinil was evaluated separately as its pharmacology is different to that of the other PS. PS were administered as a monotherapy, adjunct therapy, in oral or intravenous preparation and in comparison with a placebo or an active therapy. Most effects were measured in the short term (up to four weeks). Thirteen trials had some usable data for meta-analyses. Three trials (62 participants) demonstrated that oral PS, as a monotherapy, significantly reduced short term depressive symptoms in comparison with placebo (SMD -0.87, 95% CI -1.40, -0.33, with non-significant heterogeneity. A similar effect was found for fatigue. In the short term PS were acceptable and well tolerated. Tolerance and dependence were under evaluated. No statistically significant difference in depression symptoms was found between modafinil and placebo.

AUTHORS' CONCLUSIONS

There is some evidence that in the short-term, PS reduce symptoms of depression. Whilst this reduction is statistically significant, the clinical significance is less clear. Larger high quality trials with longer follow-up and evaluation of tolerance and dependence are needed to test the robustness of these findings and, furthermore, to explore which PS may be more beneficial and in which clinical situations they are optimal.

Cortisol hypersecretion in unipolar major depression with melancholic and psychotic features: dopaminergic, noradrenergic and thyroid correlates

Evidence supports that hyperactivity of the hypothalamic-pituitary-adrenal axis has a pivotal role in the psychobiology of severe depression. The present study aimed at assessing hypothalamic-pituitary dopaminergic, noradrenergic, and thyroid activity in unipolar depressed patients with melancholic and psychotic features and with concomitant hypercortisolemia. Hormonal responses to dexamethasone, apomorphine (a dopamine receptor agonist), clonidine (an alpha 2-adrenoreceptor agonist) and 0800 and 2300 h protirelin (TRH) were measured in 18 drug-free inpatients with a DSM-IV diagnosis of severe major depressive disorder with melancholic and psychotic features showing cortisol nonsuppression following dexamethasone and 23 matched hospitalized healthy controls. Compared with controls, patients showed (1) lower adrenocorticotropin and cortisol response to apomorphine (p<0.015 and <0.004, respectively), (2) lower growth hormone response to clonidine (p=0.001), and (3) lower responses to TRH: 2300 h maximum increment in serum thyrotropin (TSH) level (p=0.006) and the difference between 2300 and 0800 h maximum increment in serum TSH values (p=0.0001). Our findings, in a subgroup of unipolar depressed inpatients with psychotic and melancholic features, are compatible with the hypothesis that chronic elevation of cortisol may lead to dopaminergic, noradrenergic and thyroid dysfunction.

Treatments in depression

Major depression is believed to be a multifactorial disorder involving predisposing temperament and personality traits, exposure to traumatic and stressful life events, and biological susceptibility. Depression, both unipolar and bipolar, is a "phasic" disease. Stressful life events are known to trigger depressive episodes, while their influence seems to decrease over the course of the illness. This suggests that depression is associated with progressive stress response abnormalities, possibly linked to impairments of structural plasticity and cellular resilience. It therefore appears crucial to adequately treat depression in the early stages of the illness, in order to prevent morphological and functional abnormalities. While evidence suggests that a severely depressed patient needs antidepressant drug therapy and that a non-severely depressed patient may benefit from other approaches (ie, "nonbiological"), little research has been done on the effectiveness of different treatments for depression. The assertion that the clinical efficacy of antidepressants is comparable between the classes and within the classes of those medications may be true from a statistical viewpoint, but is of limited value in practice. The antidepressant drugs may produce differences in therapeutic response and tolerability. Among the possible predictors of outcome in depression treatment, those derived from clinical assessment, neuroendocrine investigations, polysomnographic sleep parameters, genetic variables, and brain imaging techniques have been extensively studied. This article also reviews therapeutic strategies used when initial treatment fails, and describes briefly new concepts in antidepressant therapies such as the regulation of disturbances in circadian rhythms. The treatment of depressive illness does not stop with treatment of acute episodes, and has to be envisaged as a continuous therapeutic intervention, of which we are still not able to determine the optimal duration of treatment and the moment that it should be ceased.

Neuroendocrine predictors of the evolution of depression

Depression is both clinically and biologically a heterogeneous entity. Despite advances in psychopharmacology, a significant proportion of depressed patients either continue to have residual symptoms or do not respond to antidepressants. It has therefore become essential to determine parameters (or predictors) that would rationalize the therapeutic choice, taking into account not only the clinical features, but also the "biological state," which is a major determinant in the antidepressant response. Such predictors can derive from bioclinical correlates and, in this context, the neuroendocrine strategy appears particularly suited. Numerous studies have investigated neuroendocrine parameters--derived mainly from dynamic challenge tests--in order to (i) determine the predictive profiles of good clinical responders to given antidepressants; (ii) monitor the progression of markers in parallel with the clinical outcome; and (iii) evaluate "in vivo" in humans the mechanisms of action of antidepressant compounds (before, during, and after treatment). This article does not attempt to be exhaustive, but rather uses selected examples to illustrate the usefulness of the investigation of the adrenal and thyroid axes and the assessment of central serotonergic, noradrenergic, and dopaminergic systems by means of neuroendocrine tests. Given methodological constraints, most of these investigations--except for baseline hormone values and the dexamethasone suppression test--cannot be used routinely in psychiatry. Despite these limitations, the neuroendocrine strategy still offers new insights in biology and the treatment of depression. Its possible expansion depends mainly on the development of specific agonists or antagonists for better investigation of the receptors supposedly involved in the pathophysiology of depression. These investigations will help define more homogeneous subgroups from a bioclinical and therapeutic viewpoint.

Serotonin transporters: implications for antidepressant drug development

Due to the complexity of the disease, several hypotheses exist to explain the etiology of depression. The monoamine theory of depression suggests that disruptions in the serotonergic and noradrenergic systems result in depressive symptoms. Therefore, the serotonin transporter (SERT) has become a pharmacological target for treating these symptoms. This review will discuss what is known about the molecular interactions of antidepressants with SERT. The effects of antidepressants on SERT regulation and expression in addition to the receptors that may be involved in mediating these effects will be addressed. Specifically, how changes to SERT expression following chronic antidepressant treatment may contribute to the therapeutic benefits of antidepressants will be discussed. Furthermore, the effects of SERT gene polymorphisms on antidepressant efficacy will be examined. Finally, a brief overview of other hypotheses of depression will be addressed as well as factors that must be considered for future antidepressant development.

The combined T3/TRH test in depressed patients and healthy controls

It is well established that depressed patients show a blunted TSH response in the TRH-stimulation test. However, it has not been investigated so far whether pre-treatment with 3,5,3'-triiodothyronine (T3) is able to further suppress the TRH-induced TSH response in depressed patients or whether it may cause an escape-phenomenon with paradoxically enhanced TSH stimulation in a subsequent TRH test. In 20 drug-free depressed patients (eight men, 12 women) suffering from a major depressive episode according to DSM-IV criteria and in 20 age- and sex-matched healthy controls, the single TRH-stimulation test (administration of 200 microg TRH at 09:00 h) was carried out followed by a combined T3/TRH test (pre-treatment with 40 microg T3 at 23:00 h the night before; administration of 200 microg TRH at 09:00 h the next day). Compared to the controls, the depressed patients showed a significantly blunted TSH response in the single TRH test. However, the percentage suppression of TRH-induced TSH stimulation after pre-treatment with 40 microg T3 was comparable in the depressive patients (61.07%) and the healthy volunteers (64.20%). Prolactin secretion did not differ between patients and controls either in the single TRH test or in the combined T3/TRH test. Apparently, in contrast to the hypothalamo-pituitary-adrenocortical (HPA) system, no disturbance of feedback control in regulation of the hypothalamo-pituitary-thyroid (HPT) axis secretion can be demonstrated in depressed patients when using the combined T3/TRH test.

Daily variations in type II iodothyronine deiodinase activity in the rat brain as controlled by the biological clock

Type II deiodinase (D2) plays a key role in regulating thyroid hormone-dependent processes in, among others, the central nervous system (CNS) by accelerating the intracellular conversion of T4 into active T3. Just like the well-known daily rhythm of the hormones of the hypothalamo-pituitary-thyroid axis, D2 activity also appears to show daily variations. However, the mechanisms involved in generating these daily variations, especially in the CNS, are not known. Therefore, we decided to investigate the role the master biological clock, located in the hypothalamus, plays with respect to D2 activity in the rat CNS as well as the role of one of its main hormonal outputs, i.e. plasma corticosterone. D2 activity showed a significant daily rhythm in the pineal and pituitary gland as well as hypothalamic and cortical brain tissue, albeit with a different timing of its acrophase in the different tissues. Ablation of the biological clock abolished the daily variations of D2 activity in all four tissues studied. The main effect of the knockout of the suprachiasmatic nuclei (SCN) was a reduction of nocturnal peak levels in D2 activity. Moreover, contrary to previous observations in SCN-intact animals, in SCN-lesioned animals, the decreased levels of D2 activity are accompanied by decreased plasma levels of the thyroid hormones, suggesting that the SCN separately stimulates D2 activity as well as the hypothalamo-pituitary-thyroid axis.

Morning and evening TSH response to TRH and sleep EEG disturbances in major depressive disorder

1. The aim of this study was to investigate hypothalamo-pituitary-thyroid axis (HPTA) functioning and sleep EEG disturbances in major depressive disorder. 2. Thyroid function was evaluated by determination of TSH levels before and after 8 AM and 11 PM TRH administration on the same day in a sample of 113 consecutively-admitted DSM-IV major depressed inpatients (72 females aged 44.3 +/- 13.0 and 41 males aged 45.7 +/- 10.7) that underwent sleep EEG recordings. 3. A blunted TSH response occurred in 15.9% for 8 AM deltaTSH (maximum increment above baseline at the 8 AM TRH challenge), in 39.8% for 11 PM deltaTSH and in 77% for deltadeltaTSH (difference between 11 PM deltaTSH and 8 AM deltaTSH). A negative correlation between deltadeltaTSH and duration of awakenings after sleep onset, and a shorter sleep onset latency in patients with a blunted 11 PM deltaTSH were found, but these two significant relationships disappeared after controlling for the effects of gender and age. 4. The present findings do not support the hypothesis that, in major depression, HPTA dysfunctioning, as reflected in TSH response to TRH, may be related to sleep EEG disturbances.

Physiological effects of electroconvulsive therapy and transcranial magnetic stimulation in major depression

Major depressive episodes are associated with dysregulation of various physiologic systems. Antidepressant medications alter regulation of the hormonal and sleep systems. A thorough understanding of these changes may elucidate the pathophysiologic basis of the disorder [Amsterdam et al., 1989: Psychoneuroendocrinology 14:43-62], and interventions targeted directly at these systems are being increasingly recognized as possible treatments for depression [Wong et al., 2000: Proc Natl Acad Sci USA 97:325-330; Szuba et al., 1996: Proc Am Coll Neuropsychopharmacol Ann Meet]. These physiologic systems are regulated by the major neurotransmitters implicated in the etiology of mood disorders--norepinephrine, serotonin, and dopamine. Many of the hormones of import for this article also act as neurotransmitters and thus alter cerebral activity themselves [Owens and Nemeroff, 1993: Ciba Found Symp 172:296-308; Weitzner, 1998: Psychother Psychosom 67:125-132]. Parenteral infusion of hydrocortisone [DeBattista, 2000: Am J Psychiatry 157:1334-1337] and thyrotropin-releasing hormone (TRH) [Prange et al., 1972: Lancet 2:999-1002; Marangell et al., 1997: Arch Gen Psychiatry 54:214-222; Szuba, 1996: Proc Am Coll Neuropsychopharmacol Ann Meet.] produce acute antidepressant effects. Antagonists to corticotropin-releasing hormone and repeated parenteral infusion of TRH may have antidepressant activity when given during several weeks [Wong, 2000: Proc Natl Acad Sci USA 97:325-330; Arborelius et al., 1999: J Endocrinol 160:1-12; Callahan et al., 1997: Biol Psychiatry 41:264-272]. Manipulations of the sleep system through sleep deprivation can ameliorate depression [Szuba et al., 1994: Psychiatry Res 51:283-295; see Wirz-Justice et al., 1999: Biol Psychiatry 46:445-453 for review]. Sleep deprivation has been shown in more than three dozen studies published in the last three decades to produce marked, acute antidepressant effects in the majority of depressed individuals [Wirz-Justice, et al., 1999: Biol Psychiatry 46:445-453]. Thus, examination of the effects the two nonpharmacologic treatments, electroconvulsive therapy (ECT) and transcranial magnetic stimulation (TMS), produce in these physiologic systems may help elucidate their mechanisms of action, while enhancing understanding of the neurobiology of depressive illness. We will review these physiologic changes associated with depression, the effects that manipulations of these systems can have on depressive disorders, and then describe the effects the two techniques that can stimulate the human brain in vivo, ECT and TMS, exert on these systems.

A novel point mutation in cluster 3 of the thyroid hormone receptor beta gene (P247L) causing mild resistance to thyroid hormone

Resistance to thyroid hormone (RTH), a syndrome characterized by variable tissue hyposensitivity to thyroid hormone (TH), is linked to mutations in the thyroid hormone receptor (TR) beta gene. We report a new family with a heretofore unreported mutation, P247L. The proposita, a 31-year-old female, presented with goiter and palpitations. RTH was suspected because of elevated serum free thyroxine (FT4) level with a normal thyrotropin (TSH). Sequencing the TRbeta gene revealed a mutation causing replacement of a proline at position 247 with leucine. Seven family members were heterozygous for the mutation, two of whom also had evidence of autoimmune thyroid disease. The mutant TRbeta had a Ka for triiodothyronine (T3) 30% that of the wild-type TRbeta, approximately a threefold reduction in T3-induced transactivation and a low level dominant negative activity when tested with a positively regulated reporter gene. In vivo sensitivity to TH was evaluated in three affected subjects by measurement of the responses to graded doses of levotriiodothyronine (LT3). Peak TSH responses to TRH were reduced and were not completely suppressed at even the highest dose of LT3, (0.9, 0.2, and 0.2, compared to < 0.01 microU/mL in unaffected controls), confirming pituitary resistance to TH in all three subjects. In contrast, peripheral tissues responded variably to LT3: serum cholesterol decreased in all by 15%-25%, serum creatine kinase decreased by 15% in two subjects and increased 35% in another, but serum ferritin and sex hormone-binding globulin increased in only one of the three affected individuals that were tested. Basal metabolic rate and sleeping pulse did not change in three and two individuals, respectively. Hyporesponsiveness to exogenous TH established the clinical diagnosis of RTH in one member of the family with a mutant TRbeta but normal tests of thyroid function at baseline. Three affected subjects had an axis I diagnosis of major depression but had Wechsler Intelligence Scale for Children, III (WISC-III) full-scale IQs (FSIQs) in the normal range. This novel TRbeta mutation is associated with a realtively mild RTH. Results of responses to LT3 underscore the variable phenotype of RTH.

Thyroid axis activity and serotonin function in major depressive episode

Recent studies in depression have reported alterations in both hypothalamic-pituitary-thyroid (HPT) axis activity and serotonin (5-HT) function; however, the functional relationships between the two systems have not been well defined in patients with major depressive episode. Thyrotropin (TSH) response to 0800 and 2300 h protirelin (TRH) challenges, and adrenocorticotropic hormone (ACTH), cortisol, and prolactin (PRL) responses to D-fenfluramine (D-FEN), a specific 5-HT releasing/uptake-inhibiting agent, were examined in 60 drug-free DSM-IV major depressed inpatients and 20 hospitalized controls. Compared with controls, patients showed lower basal serum 2300 h TSH, 2300 h maximum increment in serum TSH above baseline (delta TSH) and difference between 2300 h delta TSH and 0800 h delta TSH (delta delta TSH) levels. The hormonal responses to D-FEN (i.e. delta ACTH, delta cortisol and delta PRL) were interrelated. No significant difference in basal and post-D-FEN ACTH, cortisol or PRL values were found between controls and patients. A negative relationship between hormonal responses to D-FEN and 2300 h delta TSH and delta delta TSH values was observed in the depressed group. When patients were classified on the basis of their delta TSH test status, patients with reduced delta delta TSH values (i.e. with HPT axis abnormality) had hormonal D-FEN responses comparable to those of controls. Patients with normal delta delta TSH values (i.e. without HPT axis abnormality) showed lower ACTH, cortisol and PRL responses to D-FEN than controls and patients with abnormal delta delta TSH values. These results suggest that: (1) pathophysiological mechanisms other than 5-HT dysregulation may be involved in TSH blunting in major depressed patients; (2) 5-HT function is reduced in some depressed patients, especially those without HPT axis abnormality; and (3) HPT dysregulation may be regarded as a compensatory mechanism for diminished central 5-HT activity.

Low levels of transthyretin in the CSF of depressed patients

OBJECTIVE

Transthyretin plays an important role in the transport and distribution of thyroid hormone in the central nervous system (CNS). This study replicated and extended to patients with nonrefractory depressive illness a pilot study indicating that patients with refractory major depression have significantly lower levels of CSF transthyretin than do healthy comparison subjects.

METHOD

Lumbar punctures were performed in drug-free subjects with DSM-III-R major depression (N = 18), DSM-III-R bipolar disorder, depressed phase (N = 1), and healthy comparison subjects (N = 24). CSF concentrations of transthyretin, determined by a quantitative dot-immunobinding assay, of the depressed patients and comparison subjects were compared by analysis of covariance (ANCOVA). The relationship between CSF transthyretin levels and Hamilton Depression Rating Scale scores was determined in a subset of the depressed patients.

RESULTS

CSF concentrations of transthyretin were significantly lower in the depressed patients than in the comparison subjects by ANCOVA. Within the depressed group there was no significant overall correlation between CSF transthyretin levels and Hamilton depression scale scores, but there was a significant inverse correlation in male depressed patients (N = 8) between CSF transthyretin concentrations and Hamilton depression scores.

CONCLUSIONS

Lower CSF transthyretin concentrations in depressed patients may reflect either a stable trait in this population or a state change secondary to depression or other factors. Lower CSF transthyretin concentrations may result in altered CNS thyroid hormone homeostasis. Such alteration could account for certain mood and neurovegetative symptoms of depression and might contribute to failure of standard antidepressant treatment.

Amiodarone-Associated Depression

Objective:

To report a case of depression secondary to or aggravated by amiodarone-induced hypothyroidism.

Case Summary:

An 84-year-old white man was admitted to a psychiatric unit with severe depression approximately seven months after amiodarone had been initiated to treat paroxysmal supraventricular tachycardia. On admission, the thyroid-stimulating hormone (TSH) concentration was 11.50 μU/mL (normal 0.17–4.00) and the total thyroxine concentration was 3.9 μg/dL (4.0–11.0). About 21 months before initiation of amiodarone therapy, the TSH concentration was 2.4 μU/mL; this was the only previous TSH result available. Seven days after admission, thyroxine (levothyroxine) 25 μg/d was started. Twenty-eight days after admission, the patient's mood had improved, and the TSH concentration (2.67 μU/mL) was within normal range. The patient was discharged four days later.

Discussion:

Amiodarone contains 37.2% iodine. This is a greatly increased iodine load compared with normal intake. Amiodarone may therefore have three possible effects on thyroid function: (1) the serum concentration of thyroid hormones in clinically euthyroid patients may change, complicating assessment; (2) hyperthyroidism may occur (1–5% of patients); and (3) hypothyroidism may occur (6–10% of patients). Thus, thyroid function should be checked at least every six months. The elevated TSH concentration could indicate mild hypothyroidism or possibly be a symptom of the depressive illness. Furthermore, our patient's mood appeared to improve after he had received six to seven weeks of treatment with fluoxetine; he had also experienced depressive episodes throughout his life. Thus, particularly because the TSH concentration was only moderately raised, it is possible that amiodarone-induced hypothyroidism worsened rather than caused the depressive episode. The usual treatment for amiodarone-induced hypothyroidism is continuation of amiodarone and initiation of thyroxine at a dosage of 25–50 μg/d.

Conclusions:

This case illustrates the need to be vigilant for amiodarone-induced hypothyroidism, which may cause depression or exacerbate an underlying depressive illness. Supplemental treatment with levothyroxine may effect a rapid mood response.

Biochemical testing of thyroid function

Various published guidelines recommending serum thyrotropin (TSH)-first thyroid testing are outlined. The entities called "subclinical hypothyroidism" and "subclinical hyperthyroidism" are defined on the basis of abnormal TSH concentrations and normal values of other biochemical thyroid tests. The controversies about follow-up and treatment of these disorders are discussed. The laboratory experience of Mayo Clinic Rochester in using TSH-first thyroid testing and the subsequent implementation of a thyroid test ordering cascade are presented. Finally, recommendations are given for further optimizing laboratory testing for thyroid disorders.