The TRH test during dopamine receptor blockade in depressed patients

Effects of antipsychotics on circadian rhythms in humans: a systematic review and meta-analysis

Antipsychotics are widely used to treat psychiatric illness and insomnia. However, the etiology of insomnia is multifactorial, including disrupted circadian rhythms. Several studies show that antipsychotics might modulate even healthy circadian rhythms. The purpose of this systematic review is to integrate current knowledge about the effects of antipsychotics on the circadian rhythms in humans, and to conduct a meta- analysis with the available data. Nine electronic databases were searched. We followed the PRISMA guidelines and included randomized controlled trials (RCTs), non-RCTs, case-control studies, case series, and case reports. Of 7,217 articles, 70 were included. The available data was mainly from healthy individuals, or patients having schizophrenia, but the findings showed a transdiagnostic impact on circadian parameters. This was consistently seen as decreased amplitude of cortisol, melatonin, and body temperature. Particularly, a meta-analysis of 16 RCTs measuring cortisol rhythm showed that antipsychotics, especially atypical antipsychotics, decreased the cortisol area under the curve and morning cortisol level, compared to placebo. The data with melatonin or actigraphy was limited. Overall, this evidence about the circadian effect of antipsychotics showed a need for longitudinal, real-time monitoring of specific circadian markers to differentiate a change in amplitude from a shift in phasing, and for knowledge about optimal timing of administration of antipsychotics, according to individual baseline circadian parameters. Standardizing selection criteria and outcome methods could facilitate good quality intervention studies and evidence-based treatment guidelines. This is relevant considering the accumulating evidence of the high prevalence and unfavorable impact of disrupted circadian rhythms in psychiatric disorders.

Prolactin response to thyrotropin-releasing hormone in schizoaffective depressed compared to depressed and schizophrenic men and healthy controls

Biological tests may help clarify the relationship of schizoaffective disorder to major depressive disorder (MDD) and schizophrenia (SCZ). Thyrotropin-releasing hormone (TRH), 500 micrograms, was administered intravenously to eight schizoaffective depressed (SD), ten SCZ, 23 MDD patients and 43 healthy controls (HC), all males, ages 20-66 years and drug-free. Research Diagnostic Criteria (RDC) were utilized for establishing diagnoses, Hamilton Rating Scale for Depression (HRSD) total scores were used for assessing depressive symptoms. There were no differences in dmax PRL (post-TRH prolactin peak minus baseline, mean +/- SD) amongst SD, SCZ and HC groups (27.3 +/- 5.2, 28.8 +/- 5.4 and 31.5 +/- 5.6 ng/ml respectively). Mean dmax PRL in MDD was significantly lower than each of the other three groups (17.1 +/- 2.2 ng/ml, P less than 0.05 for all). The essentially normal PRL response to TRH in SD, significantly different from MDD but similar to SCZ parallels our previous observations on the pattern of thyrotropin (TSH) response to TRH in the same diagnostic groups. These biological findings may be taken to indicate that schizoaffective disorder, depressed subtype, is closer to schizophrenia than to major depressive disorder. However, they cannot be considered definitive evidence to that effect since schizoaffective disorders are known to be quite heterogeneous, and since the utilized biological tests lack specificity.

Thyrotropin and prolactin responses to protirelin (TRH) prior to and during chronic imipramine treatment in patients with panic disorder

The effects of protirelin [thyrotropin-releasing hormone (TRH)] administration on the release of thyrotropin (TSH) and prolactin (PRL) were examined in 14 patients with panic disorder prior to and during chronic treatment with imipramine. During imipramine treatment, the patients exhibited an increase in their TSH response to TRH (delta delta max TSH = 3.65 +/- 6.02 mu IU/ml, p less than 0.05) and in their PRL response to TRH (delta AUCPRL = 734 +/- 965 ng/ml/45 min, p less than 0.005). Several behavioral measures correlated with the neuroendocrine measures during imipramine therapy. These preliminary findings might suggest a role for changes in dopaminergic function in the clinical effects of imipramine in patients with panic disorder.

Dopaminergic control of TSH secretion in endogenous depression

To evaluate whether the inhibitory control exerted by endogenous dopamine on thyroid-stimulating hormone (TSH) secretion is altered in patients with major depressive disorder, 11 depressed patients and 9 normal controls were tested with the dopaminergic receptor antagonist domperidone (10 or 20 mg i.v.). The administration of domperidone induced a significant increase in circulating TSH levels in the normal controls, but not in the depressed patients. These data excluded the possibility that the dopaminergic inhibition of TSH secretion is enhanced in depression. To establish whether domperidone failure was due to a reduced dopaminergic tone, domperidone was administered before stimulation of TSH secretion with thyrotropin-releasing hormone (TRH) (200 micrograms i.v.). The TSH response to TRH was significantly lower in the depressed than in the control subjects, regardless of domperidone priming. However, in both groups domperidone enhanced the TRH-induced TSH release by 50%. These data suggest that the dopaminergic control of TSH secretion is not altered in patients with endogenous depression and that a reduced capacity of the pituitary to secrete TSH might be responsible for the reduced TSH responsiveness to TRH and domperidone.

Lack of effect of dopamine receptor blockade on the TSH response to TRH in borderline personality disorder

We recently reported that some patients with borderline personality disorder (BPD) exhibit a blunted thyrotropin (thyroid-stimulating hormone; TSH) response to thyrotropin-releasing hormone (TRH). Because it is known that dopamine can inhibit the TSH response to TRH and that some patients with BPD show improvement with antipsychotic (dopamine-blocking) medication, we investigated whether haloperidol could reverse the blunted TSH response in BPD. Of 12 patients with BPD, three showed a blunted TSH response that did not normalize with haloperidol. Furthermore, there were no overall group changes in TSH response with haloperidol. The present study suggests that reductions in TSH response in BPD are not secondary to dopamine.