Effects of six weeks' neuroleptic treatment on the pituitary-thyroid axis in schizophrenic patients

In order to investigate the effects of 6 weeks' neuroleptic treatment on the pituitary-thyroid axis in 25 male schizophrenic patients, and the diurnal variation in the thyrotropin (TSH) and prolactin (PRL) responses to thyrotropin-releasing hormone (TRH) in these patients, the TRH stimulation test was performed in each of them at 14.00 and 24.00 h of the same day, both before and after 6 weeks' treatment with neuroleptics (chlorpromazine or fluspirilene). Also, serum thyroxine (T4), in vitro radioactive triiodothyronine uptake (RT3 U) and free-thyroxine index (FTI) values were estimated from the pre-TRH blood sample. We found no evidence of diurnal variation in the TSH response to TRH in the schizophrenic patients, before or after 6 weeks' neuroleptic treatment. Only drug-free schizophrenic patients had significantly higher PRL responses to TRH at 14.00 h than those at 24.00 h. After 6 weeks' neuroleptic treatment, schizophrenic patients tended to have lower FTI values; also, they had significantly higher basal TSH and PRL values, as well as significantly augmented TSH and PRL responses to TRH, in comparison to their pretreatment values. These findings render possible the diagnosis of subclinical hypothyroidism in neuroleptic-treated schizophrenic patients.     

Thyroid status in senile dementia of the Alzheimer type (SDAT)

Thyroid function was investigated in a group of 21 patients with severe senile dementia of the Alzheimer type (SDAT) and in a group of 17 age and sex matched normal controls. Free thyroid hormone levels (triiodothyronine (T3) and thyroxine (T4) were measured, as were also the thyrotrophin (TSH), prolactin (PRL) and growth hormone (GH) responses to thyrotrophin releasing hormone (TRH)). When compared to controls, patients demonstrated a significantly lower free T3 value (but not free T4), a blunted TSH response to TRH, slightly elevated basal PRL and GH values and a small GH response to TRH. However, all differences were small in biological terms and were within the laboratory's normal range. This emphasizes the relative normality of neuroendocrine function, particularly thyroid status, in SDAT.     

The TRH stimulation test in Alzheimer's disease and major depression: relationship to clinical and CSF measures

A blunted thyroid-stimulating hormone (TSH) response to exogenous thyrotropin-releasing hormone (TRH) has been reported to occur consistently in patients with major depression and less consistently in patients with Alzheimer's disease (AD). In this study we compared the TSH response to TRH in a large group (n = 40) of AD patients, elderly patients with major depression (n = 17), and age-matched controls (n = 14) to further characterize how it may relate to clinical variables, baseline thyroid function tests, and cerebrospinal fluid measures. Comparisons of TRH stimulation test response across all three groups revealed that patients with major depression had lower stimulated TSH levels (delta maxTSH) (p less than 0.02) and higher (though still within normal limits) mean thyroxine (T4) levels (p less than 0.05) than the AD patients or controls. AD patients with a blunted TSH response had a significantly higher mean free T4 (FT4) level (p less than 0.03) and tended to be more severely demented (p less than 0.01) than those with a nonblunted response.     

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.     

Endocrine responses to thyrotropin-releasing hormone in major depressive disorders

The endocrine response to thyrotropin-releasing hormone (TRH) was studied in severely endogenously depressed patients during illness (n = 21) and after recovery (n = 18). The thyroid-stimulating hormone (TSH) response to TRH was blunted (deltaTSH less than 5 microIU/ml) in over one third of depressives during illness and remained blunted in most even after recovery. There was no correlation between multiple measures of cortisol secretion (the mean 24-hour plasma cortisol, dexamethasone suppression test, and plasma cortisol during the TRH procedure) and the TSH response during illness and after recovery. The TSH and prolactin (PRL) responses to TRH, as well as the baseline PRL, were significantly lower during illness. The role of possible abnormalities in dopamine and/or serotonin in depression contributing to these endocrine disturbances is discussed.     

Unaltered 24 h serum PRL levels and PRL response to TRH in contrast to decreased 24 h serum TSH levels and TSH response to TRH in major depressive disorder

The 24 h serum levels of prolactin (PRL) and thyrotropin (TSH) assessed at ten different time points and the PRL and TSH responses to TRH administration (delta PRL, delta TSH) were investigated in 26 inpatients meeting the RDC criteria for an acute major depressive disorder. Fourteen of these patients were reinvestigated in a state of partial or complete remission. Comparison between the patients during both relapse and remission and 23 healthy controls showed no differences in the paramenters reflecting the 24 h PRL levels or delta PRL. However, significantly lower 24 h TSH levels and delta TSH were found in the patient group in the acute phase. Antidepressant medication, sedatives or the outcome of the dexamethasone test did not significantly influence the PRL levels or delta PRL. Both the patient group and the controls revealed normal sleep associated PRL release indicating unaltered serotoninergic and/or dopaminergic neurotransmission regulating the PRL secretion. The present results indicate a selective disturbance affecting the pituitary TSH secretion, and are consistent with our hypothesis that the mechanism behind the decreased TSH levels and the impaired TSH response to TRH in acute major depressive disorder involves a down-regulation of the pituitary TRH receptors.     

Thyroid stimulating hormone and prolactin responses to thyrotropin releasing hormone in nondepressed alcoholic inpatients.

Thyroid stimulating hormone (TSH) and prolactin (PRL) responses to thyrotropin releasing hormone (TRH) stimulation are sometimes blunted in alcoholic subjects; however, the mechanisms involved in these phenomena have not been established. We hypothesized that elevations in free thyroid concentrations might be related to these abnormal responses and then tested that hypothesis in a sample of nondepressed alcoholic inpatients (n = 21). Four alcoholic patients had delta max TSH responses that were < 7 mIU/l; three had PRL responses at or below 8 micrograms/l. Baseline TSH was the only significant predictor of peak TSH; however, free thyroxine (FT4) and baseline TSH both were significant predictors of peak PRL. The average baseline FT4 concentration in alcoholic patients was significantly higher than that in healthy control subjects (n = 10). Our data, thus, suggest that small elevations of FT4 play a role in the inhibition of TSH and PRL responses to TRH among nondepressed, abstinent alcoholic patients.     

Neurotransmitter metabolites and endocrine responses in depression

1. Urinary 3-methoxy-4-hydroxyphenylethyleneglycol (MHPG), 3–4-dihydroxyphenylethylene-glycol (DHPG), 5-hydroxyindoleacetic acid (5-HIAA), plasma thyroid stimulating hormone (TSH), prolactin (PRL) and growth hormone (GH) were measured before and after the injection of thyrotropin releasing hormone (TRH) in healthy subjects and depressed patients with primary affective disorder.

2. The TSH response to TRH did not differ in depressed compared with control subjects. A trend (.05 < p < .10) toward a lower PRL response appeared in male depressed compared with male control subjects. GH levels did not consistently change after TRH.

3. In all subjects the TSH response correlated positively with pre- and post-TRH urinary MHPG. The PRL response correlated negatively with pre-TRH urinary 5-HIAA. Pre-TRH daytime urinary 5-HIAA levels were elevated in depressed subjects.     

Serotonergic control of TSH and PRL secretion in obese men

To evaluate whether the inhibitory control of TSH and the stimulatory control of prolactin (PRL) secretion exerted by endogenous serotonin was altered in obesity, 22 obese men and 10 normal controls were tested with TRH (200 micrograms IV bolus) in the presence (experimental test) and absence (control test) of the serotonergic agonist fenfluramine (60 mg PO 90 min before TRH). Control and experimental tests were also performed in seven male patients with subclinical hypothyroidism and were repeated in the same obese subjects after substantial weight loss. Basal TSH levels were similar in control and obese men. Normal TSH responses to TRH (peak less than or equal to 14 mU/L) were observed in all normal controls (mean peak +/- SE 9.8 +/- 0.6 mU/L). In contrast, obese men were divided into two groups: nine in whom the TRH-induced TSH rise was higher than normal (group I: mean peak = 16.5 +/- 0.5 mU/L) and 13 in whom it was normal (group II: mean peak = 10.6 +/- 0.7 mU/L). The hypothyroid men all had elevated basal and TRH-stimulated TSH levels. Basal PRL concentrations were similar in the normal controls and both groups of obese subjects. The PRL response to TRH was lower in both group I and group II obese men than in normal controls and was similar between group I and group II.(ABSTRACT TRUNCATED AT 250 WORDS)     

Effects of Gn-RH, TRH, and CRF administration on plasma leptin levels in lean and obese women

Leptin, a hormone which is produced by adipose tissue, has been shown to inhibit food intake, increase energy expenditure and influence the function of hypothalamo-pituitary-gonadal, -thyroid, and -adrenal systems. We have examined the association between leptin concentrations (RIA method) and levels of different hormones using standard Gn-RH, TRH and CRF tests (at 0, 30, 60, and 120 min) in regularly menstruating 10 lean and 10 obese premenopausal women in follicular phase. FSH, LH, estradiol (E2) and progesterone (P) concentrations in Gn-RH test; TSH, PRL, fT3, fT4 in TRH test; ACTH, DHEA-S, cortisol in CRF test were measured by RIA, ELISA or IRMA methods. The obese subjects had thicker four skinfolds, higher fat content in the body, and bigger BMI, compared to the lean females. Gn-RH test: We have noted higher basal leptin values in obese women than in lean subjects, which was stable during the Gn-RH test. In the same blood specimen, basal insulin concentrations did not differ between the tested groups of patients. There were no correlations between E(2), P, or gonadotropins and plasma leptin concentrations between both groups of patients. We have revealed the negative correlation between LH mobilization (maximal incremental values over basal levels; Delta%) and baseline leptin concentrations in all observed subjects. TRH test: In both groups of patients the leptin levels decreased at 120 min of TRH administration. We have noted diminished PRL and TSH mobilisation in obese subjects in comparison to the controls. In all females (n = 20) the correlations between TSH or PRL mobilization and BMI, skinfold thickness and the mass of body fat in kg were negative. In obese subjects only we observed the positive correlations between fT(3)concentrations at 60 and 120 min of the test or Delta% of fT(3)and leptin levels. CRF test: In obese females, we noted higher basal ACTH and cortisol concentrations with decreased mobilization (Delta%) of ACTH or cortisol, as compared to the controls. Basal leptin values were also higher in obese women comparing controls and did not significantly change within 2 h after CRF injection. In all the observed subjects (n = 20), we noted positive correlations between baseline values of leptin and ACTH, as well as negative correlation between basal concentrations of leptin and mobilisation of cortisol. The obtained results show that the hypothalamic neuropeptides may influence leptin secretion in humans.     

Neuroendocrinologic studies on autism

The cause of autism is unknown. Recently, it has been suggested that it involves metabolic disorders of serotonin and/or dopamine. On the other hand, there is a close relationship between hormone secretion and monoamines. The aim of this study was to analyze the secretion of GH, PRL, TSH, cortisol, LH and FSH. The subjects were 30 children with autism, 25 males and 5 females, aged from 1 10/12 to 9 10/12 years. Their IQs (DQs) ranged from 34 to 123. Pituitary hormone secretion was measured during provocation with insulin (0.1 unit/kg), TRH (10 micrograms/kg) and/or LH-RH (100 micrograms/m2) in 26 of 30 cases. Control subjects included 16 age-matched children with attention deficit disorder (ADD) and 18 age-matched children with mental retardation (MR) without autistic and organic central nervous diseases. The 24-hour secretion rhythm of GH, PRL and cortisol for 14 cases with autism and of LH and FSH for 9 cases was also investigated. In insulin provocation test, the peak values of GH and delta GH (peak GH level minus baseline GH level) in ADD were significantly higher than those in MR (p less than 0.05). In TRH provocation test, the peak values of TSH and delta TSH in autism were significantly lower than those in MR. Five cases of autistic children revealed borderline responses for TSH, while the only one each of ADDs and MRs revealed borderline responses for TSH. In a study of the 24-hour hormone secretion rhythm, eleven of the 14 autistic children showed an abnormal secretion rhythm.(ABSTRACT TRUNCATED AT 250 WORDS)     

Triiodothyronine administration reduces serum growth hormone levels and growth hormone responses to thyrotropin-releasing hormone in patients with anorexia nervosa

The aim of this study was to test the hypothesis that low serum T3 concentrations may promote an abnormal growth hormone (GH) response to thyrotropin-releasing hormone (TRH) in patients with anorexia nervosa. Eight anorexic women and two anorexic men, ages 15-25 years, with low free T3 circulating levels (mean +/- SEM = 2.8 +/- 0.3 pmol/l) were studied. A TRH test (200 micrograms IV) was carried out under basal conditions and repeated following treatment with oral T3 (1.5 micrograms/kg BW/day) for eight days. Following T3 administration, GH levels dropped significantly from a baseline of 7.1 +/- 1.3 micrograms/l to 3.1 +/- 0.7 micrograms/l (p less than 0.02), as did GH peak responses to TRH (9.0 +/- 1.0 micrograms/l vs 4.4 +/- 0.8 micrograms/l, p less than 0.01). ANOVA and analysis of area under the curve (AUC) confirmed that after T3 treatment there was a significant reduction in TRH-induced GH release in these patients (GH AUC: 902 +/- 132 micrograms/l vs. 456 +/- 91 micrograms/l, p less than 0.02). TSH responses to TRH, which were normal prior to T3 treatment, completely disappeared following it, and PRL responses to TRH also were diminished. Although our experimental approach does not permit a conclusion that low T3 levels were the primary reason for these changes, the data support the theory that low T3 circulating levels may facilitate abnormal GH secretion and the GH-releasing activity of intravenous TRH.     

Thyrotropin and prolactin response to thyrotropin-releasing hormone in depressed and nondepressed alcoholic men

Thyrotropin-releasing hormone (TRH) stimulation tests were performed on 81 alcoholic men after at least 3 weeks of abstinence. Subjects were given 500 micrograms of TRH intravenously, and thyroid-stimulating hormone (TSH) and prolactin (PRL) were measured at baseline, and then 15 and 30 min later. Comparisons were made among alcoholics with (n = 27) and without (n = 54) a lifetime history of depression as determined by the Diagnostic Interview Schedule. Nine nondepressed, nonalcoholic subjects served as controls. Alcoholics with or without a depression history did not differ from each other or from control in TSH or PRL response area under the curve. Blunted TSH responses were present in 10 (12%) of the alcoholics and none of the controls when blunting was defined as a delta max TSH less than 5 microU/ml. When blunting was defined as a delta max TSH less than 7 microU/ml, 18 (22%) of the alcoholics and 1 (1%) of the controls were blunted. Conversely, 2 (2.5%) of the alcoholics had a delta max TSH greater than 32 microU/ml. All subjects were clinically euthyroid. Contrary to expectation, depressed subjects were slightly less likely to show blunted responses than nondepressed subjects. No relationship was found between neuroendocrine measurements and several measurements of alcoholism or depression. Some alcoholic subjects show a blunted TSH response to TRH injection, which may be a function primarily of the alcoholism itself. The precise mechanism remains unknown.     

Effect of TRH on TSH and prolactin levels in affective disorders

The thyrotropin-releasing hormone (TRH) test was studied in 32 patients with acute major depressive disorder, 16 patients with recurrent unipolar (n = 8) or bipolar (n = 8) affective disorder in remission, and 22 healthy control subjects. Twenty-six of the 32 acutely ill patients were also studied when in remission. Outcome in these patients was correlated to serum levels of triiodothyronine (T3), 3,3',5'triiodothyronine (reverse T3), thyroxine (T4), thyroid-stimulating hormone (TSH), prolactin (PRL), melatonin, dexamethasone suppression test (DST) results, and clinical symptoms assessed by the Comprehensive Psychopathological Rating Scale (CPRS). The TSH response to TRH (delta TSH) was decreased in the acutely ill patients, but no difference was found between patients in remission and controls. The delta TSH was correlated to TSH but not to T3 and T4 levels in both acutely ill and control subjects. In the acutely ill group, delta TSH did not distinguish between patients with normal and abnormal DST results. Thus, abnormalities in the hypothalamic-pituitary-thyroid (HPT) axis are not correlated to abnormalities in the hypothalamic-pituitary-adrenal (HPA) axis. Moreover, delta TSH did not differentiate between melancholic (DSM-III) and nonmelancholic patients or between patients with primary and secondary depression. No correlation was found between delta TSH and CPRS scores. Patients with observable agitation greater than 0.25 points (item range 0-3) had higher levels of delta TSH than patients with lower levels. No significant correlation was found between delta TSH and seven specific symptom clusters on the CPRS. However, there was a possible relation between low delta TSH and violent suicide attempts or suicide. PRL levels did not distinguish acutely ill patients from controls. Finally, there was no significant regression between delta TSH and melatonin levels. The decrease in delta TSH seen in the acutely ill patients was too small to be of diagnostic value as a laboratory measure differentiating acutely ill and healthy subjects. The mechanism underlying the HPT alterations in acute major depressive disorder may be a desensitization of the TRH receptor in the thyrotrophs secondary to an increased endogenous TRH stimulation.     

Lack of correlation between cerebrospinal fluid thyrotropin-releasing hormone (TRH) and TRH-stimulated thyroid-stimulating hormone in patients with depression.

BACKGROUND: It has been proposed that elevated central thyrotropin-releasing hormone (TRH) is associated with the blunted thyroid-stimulating hormone (TSH) response to TRH in patients with depression. Few studies have directly evaluated this relationship between central nervous system and peripheral endocrine systems in the same patient population. METHODS: 15 depressed patients (4 male, 11 female, 12 bipolar, and 3 unipolar) during a double-blind, medication-free period of at least 2 weeks duration, underwent a baseline lumbar puncture followed by a TRH stimulation test. Cerebrospinal fluid (CSF) TRH and serial serum TSH, free thyroxine, triiodothyronine, prolactin, and cortisol were measured. A blunted response to TRH was defined as a delta TSH less than 7 microU/mL. RESULTS: There was no significant difference in mean CSF TRH between "blunters" (2.82 +/- 1.36 pg/mL) and "non-blunters" (3.97 +/- 0.62 pg/mL, p = .40). There was no evidence of an inverse relationship between CSF TRH and baseline or delta TSH. There was no correlation between CSF TRH and the severity of depression or any other endocrine measure. CONCLUSIONS: These data are not consistent with the prediction of hypothalamic TRH hypersecretion and subsequent pituitary down-regulation in depression; however, CSF TRH may be from a nonparaventricular nucleus-hypothalamic source (i.e., limbic area, suprachiasmatic nucleus, brain stem-dorsal raphe) and thus, not necessarily related to peripheral neuroendocrine indices.     

Effect of thyroliberin treatment on the thyrotropin and prolactin levels in patients with amyotrophic lateral sclerosis

The blood serum TSH and PRL levels were studied in 12 ALS patients after TRH stimulation. The TSH test was repeated after 4-weeks TRH treatment. The results were compared with the data obtained in the control group. It was shown that after TRH stimulation the TSH responses did not reveal greater abnormalities, but PRL responses were significantly diminished. The results could confirm our previous observations concerning the dysregulation of dopamine metabolism in ALS patients.     

TRH-induced prolactin release is blunted in females with endogenous unipolar major depression

Twenty-five women with unipolar primary major depressive disorder (20 endogenous, 5 nonendogenous) and 20 female control subjects were studied with the thyrotropin-releasing hormone stimulation test (TRH-ST). Prolactin (PRL) levels were measured before and after TRH administration for patients and control subjects. For patients, thyrotropin (thyroid-stimulating hormone; TSH) levels were measured from the same serum specimens as PRL levels, and the 1 mg dexamethasone suppression test (DST) was performed. Patients with endogenous depression (ED) had significantly lower maximal serum PRL levels (max PRL) following TRH, and a significantly reduced increase over basal serum PRL (delta max PRL) compared to normal controls (NC). Nonendogenous depressed (NED) patients did not differ significantly from the ED or NC groups on either of these measures. For the ED group, delta max PRL was inversely correlated with severity of depressive symptomatology. Basal PRL levels did not differentiate the depressed subgroups (ED, NED) from each other or from the NC group. Depressed patients with blunted delta max PRL values tended to have blunted delta max TSH values and vice versa. Almost all patients with blunting of either delta max PRL or delta max TSH were also DST nonsuppressors; conversely, only about half (7 of 12) of patients who were DST nonsuppressors had either blunted delta max PRL or delta max TSH. Patients with clinical diagnoses of melancholia or psychotic features were significantly more likely to have blunted delta max PRL values than patients without these diagnoses. A disturbance of central noradrenergic function could explain these findings.     

Thyroid hormones and TSH, prolactin and LH responses to repeated TRH and LRH injections in depressed patients.

Twelve patients with unipolar depressive disorders received 600 microgram of synthetic TRH or LRH, in a random order, for 3 days each. Placebo injections were given as two 3-day courses prior to and between the active treatments. Serum TSH, prolactin (Prl) and LH were measured by radioimmunoassays prior to the experiment as well as immediately before and 20 min after each injection. Serum T4 and T3 were determined by radioimmunoassays before the treatments and 24 h after the first two TRH injections. Serum T4 level in depressed patients did not differ from controls. Serum T3 level in depressed patients was significantly below, and the reverse T3 level was slightly above the normal mean. However, the latter difference was not statistically significant due to the large variation of rT3 levels among the depressed patients. The TSH responses did not differ from that of controls after the first injection but the responses after the second injection were lower than in a control study. The Prl responses to TRH were sub-normal in seven out of eight patients. Blunted LH responses to LRH were seen in three patients.     

Gender differences in TRH-stimulated TSH and prolactin in primary degenerative dementia and elderly controls

We performed thyrotropin-releasing hormone (TRH) stimulation testing in 18 nondepressed patients with primary degenerative dementia (10 M, 8F; average age +/- SD = 68 +/- 7) and 12 elderly controls (7M, 5F; average age +/- SD = 61 +/- 6). Six patients were retested approximately 2 years later. Initial Mini-Mental State Examination scores for patients ranged from 2 to 28 (average +/- SD = 18 +/- 6) and the scores for the control subjects were all equal to 30. Protirelin (500 micrograms) was injected iv and blood was sampled at 0, 15, 30, 45, 60, and 90 min for thyrotropin-stimulating hormone (TSH) and prolactin (PRL). There were no significant differences between patients and controls in baseline T4, T3 uptake, TSH, or PRL. No significant differences were found between patients and controls for either TRH-stimulated TSH or PRL at all time points. Duration of illness, severity of dementia, and severity of depressive symptoms did not correlate significantly with stimulation test results. There were, however, significantly greater responses in stimulated TSH and PRL for women compared with men in both patients and controls. Upon repeat testing (n = 6), TRH-stimulated TSH and PRL were not significantly different from the initial results.     

Different neuroendocrine profiles of remitted and nonremitted schizophrenic patients

BACKGROUND: Thyrotropin-releasing hormone (TRH) test and Dexamethasone Suppression Test (DST) are two neuroendocrine tests that have been extensively used in an attempt to predict treatment response and outcome in schizophrenia. The objectives of this study were to investigate (1) the relationship between TRH test and DST and various psychiatric symptoms and (2) the potential value of these tests in prediction of short-term outcome in schizophrenic patients. METHODS: TRH test and DST were administered to 58 patients with schizophrenia. All patients were evaluated with a battery of rating scales before neuroendocrine test procedures and at regular intervals for 1 year. Patients were divided into two groups as remitted (RP; n = 30) and nonremitted patients (NRP; n = 28). Baseline results of these two groups were compared with each other and 30 healthy controls. RESULTS: Basal levels of total T3 (T3T) and free T3 (T3F) were higher in RP group than controls. Basal prolactin (PRL) level was higher in RP group, but not in NRP, compared to controls. Basal growth hormone (GH) and thyroid-stimulating hormone (TSH) levels of NRP were significantly higher than those of RP. DST nonsuppression was observed at a significantly higher rate in RP than NRP and control group. Blunted TSH response rate in RP group was higher significantly compared to other two groups. CONCLUSIONS: The data implicate that higher basal TSH and GH levels may be associated with a poorer treatment response, whereas higher total and free T3 levels, a blunted TSH response to TRH and nonsuppression on the DST may indicate a better response in schizophrenics.