The thyrotropin (TSH) and prolactin (PRL) responses to protirelin (TRH) were studied in 62 female unipolar depressive patients, 24 delusional (psychotic) and 38 nondelusional (Diagnostic and Statistical Manual [DSM]-III-R criteria). The TSH response to TRH was blunted (≤6 μlU/mL) in ten of the 24 delusional (41.6%) and in 18 of the 38 nondelusional (47.4%) patients, the difference being not significant. The TSH and PRL responses to TRH, calculated as area under the curve, were not different between the two groups. Similar results were obtained when the response patterns were compared by repeated measure analysis of covariance.

The development, evaluation and use of biological markers with a diagnostic purpose in psychiatry is extremely important. However, with certain exceptions, truly sensitive and specific markers have not yet emerged. In order to investigate the relationship between the immune apparatus and the hypothalamic-pituitary activity on the one hand, and the psychopathological state of the patients on the other, we used a longitudinal design and assessed monocyte parameters (HLA-DR, CD 35, vimentin filaments, and phagocytosis index) and neuroendocrine tests (dexamethasone suppression test [DST] and thyrotropin-releasing hormone [TRH] stimulation test) at intake and at follow-up in 49 depressed patients. Immunological parameters were compared with neuroendocrine tests in both phases of the study. The combined use of both immunological and neuroendocrine tests did not add sensitivity to the immunological identification of depressed patients. The findings lead us to consider the role of the monocyte parameters as sensitive depressive state markers, while the combined use of both neuroendocrine and immunological tests in current clinical practice would be debatable.

Final conclusions and data comparisons from the thyrotropin-releasing hormone (TRH) test results are made difficult by differences in test implementation methods, ie, TRH different administration routes, dosages and blood sampling times. A number of statistical analyses are feasible, which may also influence test interpretation. The authors review some types of statistical analyses and suggest using the area under curve (AUC) method as a means of evaluation. The TRH test was performed before treatment and after a 5-day wash-out period, in 40 depressed patients hospitalized in the Psychiatric Unit of Besancon Teaching Hospital (Centre Hospitalier Universitaire de Besançon). Variation analyses performed by peak and threshold comparison (7.0 IµU/ml) and by the AUC method (386 IµU/ml) in positive and negative patients revealed some statistical differences.