Diagnostic and therapeutic value of testing stimulation of thyroid-stimulating hormone by thyrotropin-releasing hormone in 100 depressed patients

[Therapeutic strategies for depression]

To date, no one antidepressant medication has been proven to be more efficient than another. Physicians are still waiting for good criteria to select which antidepressant has more chances of being effective in certain patients. Nevertheless, guidelines for antidepressant prescription could improve the rate of success in treating depression. All antidepressant medications share the same indication: a major depressive episode. Some compounds have indications other than a major depressive episode, which may be taken into account by the prescribing physician. Many researchers have tried to identify predictive criteria of response to antidepressants. The predictive clinical criteria include: endogeneity, early response, severity and duration of depression, pathological personality traits, quality of the environment, and co-morbid organic abnormalities. Paraclinical criteria have also been studied: levels of monoamines, neuro-endocrinological parameters, enzymatic activities, polysomnography, and brain imaging. Different recommendations have been proposed to guide therapeutic strategies from the acute period to the post-acute period, but three items have been mentioned most often: risk of negative side effects, patient expectations, and level of proof of efficacy of the compounds. Mild to moderate major depressive episodes raise a difficult question: can psychotherapy be an alternative option to antidepressant medication?

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.

Effects of electroconvulsive therapy on the thyrotropin-releasing hormone test in patients with depression

We investigated the acute and lasting effects of electroconvulsive therapy (ECT) on the thyroid-stimulating hormone (TSH) response to thyrotropin-releasing hormone (TRH) in patients with depression. The TRH stimulation test was conducted (1) under basal conditions, after a first ECT, and at the end of a therapeutic course of 7 ECTs in 20 inpatients with depression; (2) before the initiation of antidepressant therapy and after the therapeutic response in 16 other inpatients with depression who responded to antidepressant drug treatment; and (3) in 20 healthy control subjects. Baseline TSH levels were lower in patients with depression, especially in those with more severe depression who were considered appropriate for ECT. Before the treatment, TSH response to TRH did not differ between the patients with depression and controls; however, more blunted TSH responses to TRH were observed in these patients compared with the controls. TSH response to TRH changed neither with one ECT nor throughout consecutive ECT sessions in patients with depression. Drug treatment also was found to have no impact on this response. These findings suggest that the therapeutic action of ECT in depression is not directly related to its effects on the hypothalamic-pituitary-thyroid axis. However, possible delayed effects of ECT on the HPT axis function should not be overlooked.

The hypothalamic-pituitary-thyroid axis in major depression

We investigated the capacity of several thyroid-axis measures to distinguish between depressed and control subjects and determined whether these variables were related to antidepressant treatment response. We studied 105 subjects who fulfilled the DSM-III-R criteria for a current major depressive episode and 41 volunteers with no current mental disorder. The following thyroid-axis variables were measured: difference between T4 levels at 09.00 hours and 13.00 hours; baseline TSH; maximal TSH response to 400 micrograms TRH (delta max TSH); and presence of a blunted delta max TSH. The T4 difference variable alone distinguished between depressed and control subjects. In multivariate analyses, T4 difference and delta max TSH were independently related to antidepressant-treatment outcome, and predicted a modest proportion (14%) of the variance in outcome. The relationship between these two variables and treatment outcome was particularly strong in depressed male subjects who were receiving desipramine, for whom they accounted for 36% of the variance in treatment outcome. The T4 difference variable both distinguished between depressed and control subjects and was related to treatment outcome. Although this finding requires replication, it is consistent with other reports of the usefulness of thyroid-axis indices measured at different times of day in depressed patients.

Neuroendocrine and sleep variables in major depressed inpatients: role of severity

To evaluate the reliability of the endogenous concept of depressive illness according to the Newcastle Endogenous Depression Diagnostic Index (NEDDI), 155 major depressive inpatients with NEDDI scores > or = 6 (endogenous) were matched for gender and age (+/- 5 years) to 155 major depressive inpatients with NEDDI scores < 6 (nonendogenous). When sleep polygraphic variables, neuroendocrine parameters (dexamethasone suppression and thyrotropin-releasing hormone tests), and various clinical variables (unipolar/bipolar status, psychotic/nonpsychotic subtype, and severity of the depressive episode) were examined, statistically significant differences between endogenous and nonendogenous patients emerged for three variables: the thyroid-stimulating hormone response to the thyrotropin-releasing hormone test, the dexamethasone suppression test response at 16:00 h, and the percentage of time awake during the night. However, when the effects of age and severity of depression were controlled, those differences disappeared.

Sensitive assay of thyroid stimulating hormone in depressed patients

A decreased thyroid stimulating hormone (TSH) response to thyrotropin releasing hormone (TRH) has been noted in major depression. Some authors found a positive correlation between baseline TSH levels and TSH response to TRH, especially with sensitive assays of TSH. Serum TSH was assayed by a sensitive method in 55 depressed patients and 38 healthy volunteers. Patients were subclassified according to DSM-III as suffering from major depression (n = 40) and non-major depression (n = 15). The patients' mean score on the Hamilton Rating Scale for Depression (HRSD) was 50 (SD = 10). The TSH value was significantly lower in depressed patients compared with healthy control subjects, and in major compared with non-major depression. No differences in TSH levels distinguished the various subtypes of major depression. There was a significant negative correlation between global HRSD scores and TSH concentrations. The most anxious patients tended to have significantly lower TSH values compared with the least anxious subjects. Total HRSD insomnia scores correlated negatively with TSH concentrations after log transformation. The sensitive determination of TSH may also provide an index of thyroid function in depression that is simpler to implement than measurements of the TSH response to TRH.

TSH response to TRH and EEG sleep in non-bipolar major depression: a multivariate approach

The TSH response to TRH and selected sleep EEG variables were studied in a homogeneous sample of 280 non-bipolar major depressed inpatients (95 males and 185 females). The TSH response to TRH was blunted in 28% of the sample. delta max TSH was correlated negatively with age, Hamilton rating scale, Newcastle scale, percentage of wake, and positively with basal TSH, percentage of stage II, slow wave sleep, REM sleep and REM latency. delta max TSH was also lower in male patients and in patients suffering from an endogenous or a psychotic subtype of major depression. Basal TSH was only correlated negatively with the Newcastle score. In view of intercorrelations between all these variables, and because of the confounding effect of age, gender and severity on both the TSH response to TRH and sleep EEG variables, a multiple regression analysis was performed and demonstrated that basal TSH and gender were the two variables with the highest contribution to the delta max TSH variance, followed by age and the presence of psychotic symptoms. When controlling strictly for these significant effects, correlation with the severity or with the endogenous character of depression, and with sleep EEG parameters disappeared.

The role of psychosocial and biological variables in separating chronic and non-chronic major depression and early-late-onset dysthymia

Psychosocial (sociodemographic characteristics, loss and separation and family atmosphere in childhood, recent life events) and biological (family history, DST, TRH-test) variables were investigated in 180 patients with Major Depression (MD) and Dysthymic Disorder (DD). The aim of the study was to reveal certain differences between the chronic and non-chronic course of MD and the early- and late-onset subtypes of dysthymia. When comparing the two course patterns of MD, a higher rate of malignant tumours among first-degree relatives, a greater number of long-lasting stress situations before the index depressive episode, longer duration of the previous episodes, less frequent DST nonsuppression, and a blunted TSH response to TRH were found in patients with a chronic course of MD. Several factors seem to influence the course pattern of MD, or else the chronic form represents a subgroup within MD. The late-onset dysthymics were mainly women with a low level of education, a lower suicidal tendency, normal suppression in DST, and a lack of blunted TSH responses to TRH administration during the period of double depression. The early-onset dysthymics showed a higher number of persons who had never married, who presented a more traumatic and frustrating childhood background, and who had a higher rate of DST non-suppressors and blunted TSH responses after TRH administration during the period of their double depression. Our data suggest that late-onset dysthymia might be a biologically distinct subgroup of chronic depression.

Biological markers as classifiers for depression: a multivariate study

1. Delta TSH, REM latency, 4 pm and 11 pm post-dexamethasone cortisol values were determined after a wash-out period in a group of 74 non-selected depressed patients who were diagnosed (according to RDC with the SADS) as follows: 46 definite and 10 probable MD, 4 minor and 14 intermittent depression. 2. These biological variables, as well as gender, age and basal TSH were introduced in a principal component analysis. The four first PC scores explaining up to 77% of the data set were further calculated for each patients and used in a cluster analysis. A three clusters solution was retained. 3. DST escape and increased TSH response to TRH each identified subgroups of depressed patients. Conversely, blunted TSH response or REM latency were inefficient to classify patients. 4. Thus, HPA hyperactivity characterized CL-I patients (n = 29). These were more severely depressed, displayed more endogenous features and were reported as being more anxious. 5. Increased TSH response to TRH identified CL-III, exclusively composed of female patients (n = 10) that displayed more apparent sadness and tended to be older. 6. In CL-II, the usual sex-ratio for depressive illness was reversed and patients (n = 35) exhibited the least HPA axis disturbances and the same rate of blunted TSH response than in CL-I. They were also less severely depressed, displayed less endogenous characteristics and were rated as more mood reactive. 7. These results suggest heterogeneity in biological disturbances in depression and further stress the importance for controlling age, gender and severity of illness in studies investigating biological markers in depression.