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.

The dexamethasone suppression test in a group of research diagnostic criteria schizoaffective depressed men.

A dexamethasone suppression test (DST) was performed on 8 schizoaffective depressed men. Cross-sectional comparisons were made with three groups: schizophrenics (n = 10), unipolar major depressives (n = 23) and healthy controls (n = 43). All were drug-free and similar in age and body weight. Evaluations utilized the Research Diagnostic Criteria (RDC) for diagnosis, and the Hamilton Rating Scale for Depression for depressive symptom rating. DST nonsuppression, defined as a blood cortisol level of greater than or equal to 5.0 micrograms/dl at 16.00 h postdexamethasone, was observed in 43.5% of the major depressive disorder patients. This was different from the other three groups: 12.5% in schizoaffective depressed, 10.0% in schizophrenics and 9.3% in healthy controls (p less than 0.01, p less than 0.01, and p less than 0.001 respectively). Although schizoaffective depressed patients were significantly different from major depressive disorder patients in their DST responses, both groups were similar in their total HRSD scores and different from the schizophrenics (p less than 0.01 for each). These results, together with others previously reported by us on the thyrotropin-releasing hormone challenge in the same diagnostic groups, may be taken to mean that schizoaffective disorder, depressed type, is biologically distinct from major depressive disorder but not schizophrenia. On the other hand, until further corroborated, they should probably be considered a reflection of the heterogeneity of the schizoaffective syndrome and the nonspecificity of the DST.

Pharmacologic provocation and dexamethasone suppression test sensitivity.

In expectation of improving sensitivity, the standard 1-mg dexamethasone suppression test (DST) was given to 10 depressed inpatients and repeated with theophylline or caffeine and again following 3 days of lorazepam with abrupt discontinuation. Two patients showed nonsuppression on the standard DST; 2 suppressors changed to nonsuppression after lorazepam discontinuation, and 1 also changed after theophylline. This increase from 20 to 40% sensitivity remains significantly less than a desirable minimum 80% sensitivity (p less than 0.001), which suggests that a consistent DST sensitivity of 80% in melancholia is unlikely to be attained.

Relationship of age to TSH response to TRH in depressed men.

The relationship between age and TSH response to TRH was studied in 40 men with unipolar major depressive disorder (range 24-65 years, mean 44.7 years) and 36 healthy male volunteers of similar ages. Both groups were subdivided into younger and older than 40 years of age. "Blunted" TSH response to TRH was observed in 58% of depressed men and in 28% of controls, using a dTSH maximum of less than or equal to 6 microU/ml as a cut-off criterion. Older healthy men had a higher blunting rate (40%) than the younger group (19%). In depressed patients, by contrast, the blunting rate was 50% in the older group and 65% in the younger group. Higher mean maximum dTSH, higher basal TSH and lower mean circulating FT4 levels were also noted in older depressed men, suggestive of a subtle thyroid subsensitivity to TSH stimulation and subclinical primary hypothyroidism that may have contributed to the depression. Age is known to be a confounder of TRH test results. There may be a subset of depressed patients over 40 where the confounding effect of age is associated with an exaggerated, rather than decreased TSH response to TRH.

Thyrotropin response to thyrotropin-releasing hormone in RDC schizodepressed men.

Biological tests may help clarify the relationships of schizoaffective disorder to both major depressive disorder and schizophrenia. Thyrotropin-releasing hormone (TRH), 500 micrograms i.v., was administered to 14 schizodepressed, 23 schizophrenics, 41 unipolar major depressives (all by RDC) and 45 healthy controls, all males 20-67 years old with no significant differences in age, body height or weight. Results showed no differences in maximal delta TSH (dTSH max) amongst schizoaffective depressed, schizophrenia and healthy control groups (10.1 +/- 1.3, 9.2 +/- 1.1, 9.7 +/- 0.8 microU/ml, means +/- SEM respectively). Mean major depressives' dTSH max was lower than in each of the other three groups (6.2 +/- 0.4 microU/ml, P less than 0.01 for all). Utilizing a less than or equal to 5.0 microU/ml cut-off criterion for blunting, the schizodepressed had 36%, schizophrenics 44%, healthy controls 22% and major depressed 59% blunters (P less than 0.05 from other three groups). Schizodepressed patients appeared significantly different from major depressed but closer to schizophrenics (and healthy controls) on the TRH test.

Sex differences in prolactin change during mourning.

Fourteen men and 12 women were interviewed eight weeks after conjugal bereavement to discuss the events prior to the spouse's death and the subsequent bereavement period. Prolactin (PRL) was measured at the beginning and end of the interview. Descriptions of the deceased spouse were obtained during the interview and rated for Developmental Level of Object Representation (DLOR), a measure of the cognitive complexity of the description. There were significant correlations between DLOR and PRL change for both men and women but the correlation for women was positive and the correlation for men was negative. These findings extend the literature on the psychological correlates of PRL change and suggest that the physiological changes associated with mourning are different for men and women.

Characterization of the pituitary response in the TRH test by kinetic modeling.

Applying the principles of chemical kinetics to the time course of TSH concentrations after TRH infusion, individual values for total TSH release from the pituitary, TSH elimination and release rates, and latency for TSH release were found for 40 patients. Justification for using the observed peak TSH elevation as a consistent reflection of the total TSH release was provided by the high correlation between these two (r = 0.97, P less than 0.001). Kinetic modeling indicated that the most consistent reflection of total pituitary TSH response is the TSH elevation over baseline 35 min after TRH (with the peak expected 30 min post-TRH), rather than the area under the curve.