Paranoid schizophrenics may not use irrelevant signals. The use of measures of blocking and of urinary dopamine.

Conditioned blocking tests for the use of superfluous (irrelevant) information in task-solving. Paranoid psychotic, obsessive-compulsive and healthy subjects usually showed normal blocking, but non-paranoid subjects tended to learn about the superfluous stimulus. Attenuated blocking was usually associated with increased dopamine utilization measured in 24h urine samples. This may reflect poor stabilization of response to neuroleptic medication.

Sustained urinary norepinephrine and epinephrine elevation in post-traumatic stress disorder.

Urinary norepinephrine and epinephrine levels (microgram/day) were measured at two-week intervals during the course of hospitalization in the following patient groups: post-traumatic stress disorder (PTSD); major depressive disorder (MDD); bipolar I, manic (BP); paranoid schizophrenia (PS); and undifferentiated schizophrenia (US). The mean norepinephrine level during hospitalization was significantly higher in PTSD (76 +/- 10.4 micrograms/day) than in BP (60.6 +/- 8.4 micrograms/day), MDD (41.2 +/- 4.7 micrograms/day), PS (33.4 +/- 4.9 micrograms/day) and US (34.3 +/- 5.9 micrograms/day) groups, according to Duncan's multiple range test, (F(4,39) = 6.94, p less than 0.0003). The norepinephrine elevations in the PTSD group were sustained throughout hospitalization. The only other group to show mean levels in this range was the BP group in the first sample after hospital admission. This finding supports prior psychophysiological studies indicating increased sympathetic nervous system activity in PTSD patients. The mean epinephrine level during hospitalization was also significantly higher in PTSD (22.7 +/- 2.4 micrograms/day) than in MDD (13.6 +/- 1.7 micrograms/day), PS (14.7 +/- 2.4 micrograms/day), and US (18.9 +/- 1.8 micrograms/day), but not higher than in BP (21.5 +/- 2.7 micrograms/day). The relationship of epinephrine levels among diagnostic groups was sustained throughout hospitalization. It appears likely that the main underlying mechanisms for elevations of both hormones are psychological, but further work will be required to establish the exact nature of these mechanisms.

Urinary free-cortisol levels in posttraumatic stress disorder patients.

Urinary free-cortisol levels (micrograms per day) were measured by radioimmunoassay at 2-week intervals during the course of hospitalization in the following patient groups: posttraumatic stress disorder (PTSD); major depressive disorder; bipolar I, manic; paranoid schizophrenia; and undifferentiated schizophrenia. The mean cortisol level during hospitalization was significantly lower in PTSD (33.3 +/- 3.2) than in major depressive disorder (49.6 +/- 5.9), bipolar I, manic (62.7 +/- 6.7), and undifferentiated schizophrenia (50.1 +/- 8.9), but was similar to that in paranoid schizophrenia (37.5 +/- 3.9). The same differences across groups are evident in the first sample following hospital admission. This finding of low, stable cortisol levels in PTSD patients is especially noteworthy, first because of the overt signs of anxiety and depression, which would usually be expected to accompany cortisol elevations, and second because of the concomitant chronic increase in sympathetic nervous system activity shown in prior psychophysiological studies of PTSD and reflected in marked and sustained urinary catecholamine elevations previously reported in our own PTSD sample. The findings suggest a possible role of defensive organization as a basis for the low, constricted cortisol levels in PTSD and paranoid schizophrenic patients. The data also suggest the possible usefulness of hormonal criteria as an adjunct to the clinical diagnosis of PTSD.

Homovanillic acid (HVA) urinary excretion and day/night rhythm of chronic schizophrenic patients. Preliminary observations.

The authors report, as compared to healthy subjects, a higher daily excretion and a higher urinary variations of homovanillic acid (HVA) for schizophrenic chronic paranoid patients (patients with positive symptomatology predominating, CROW,s type I). Inversely, a lower HVA excretion and probably an inversion of the circadian rhythm of urinary HVA were found for schizophrenic chronic undifferentiated patients (patients with negative symptomatology predominating, CROW's type II). These results have to be confirmed by the study of a greater number of patients and the measure, for comparison among themselves, of other precursors and metabolites of monoamines.

Cross-cultural study of a biochemical abnormality in paranoid schizophrenia.

We studied 24-hour urinary excretion of phenylethylamine (PEA) and creatinine in 50 schizophrenic (39 paranoid and 11 nonparanoid) and 19 nonpsychiatric patients from Bombay, India. Methods for diagnosis, clinical assessment, and 24-hour urine collection were identical to those used in an earlier study done in a Washington, D.C. hospital. Clinical evaluations were done in Bombay, while urinary PEA and creatinine estimations were performed at NIMH, Washington, without knowledge of the subjects' identify. Paranoid schizophrenic patients had significantly greater 24-hour urinary excretion of PEA than both nonparanoid schizophrenic patients and nonpsychiatric controls. The mean amount of PEA per g creatinine in urine was also highest of paranoid schizophrenic patients. Our findings provide cross-cultural support to the possibility of abnormal PEA metabolism in at least some patients with paranoid schizophrenia.

Urinary tryptamine excretion in chronic schizophrenics with low platelet MAO activity.

Reduced platelet MAO activity has been previously reported as a biochemical marker for a subgroup of psychiatric patients, including some chronic schizophrenics. As tryptamine metabolism appears to be sensitive to alterations in MAO activity, urinary tryptamine excretion was measured in chronic schizophrenics with low platelet MAO activity, chronic schizophrenics with normal platelet MAO activity, and age-matched and sex-matched controls. The increased urinary tryptamine excretion observed in chronic schizophrenics with low platelet MAO activity may reflect a pathophysiologic mechanism associated with low MAO activity.

Phenylethylamine in paranoid chronic schizophrenia.

Phenylethylamine (PEA) is an endogenous amine that is structurally and pharmacologically related to amphetamine. Urinary PEA excretion is significantly higher in paranoid chronic schizophrenics than in nonparanoid chronic schizophrenics and normal controls. Diet, hospitalization, and medication do not account for differences in PEA concentrations. These findings offer some indication that PEA may be an endogenous amphetamine.

[Excretion of 3,4-dimethoxy phenylethylamine in the urine of schizophrenics]. / Uber die Ausscheidung von 3,4-Dimethoxyphenyläthylamin im Urin von Schizophrenen

According to the hypothesis of Osmond, Harley-Mason and Smythies on abnormal methylation products in the catecholamine metabolism in schizophrenics, the excretion of 3,4-dimethoxyphenylethylamine (3,4-DMPEA) in the urine was examined in 80 patients with endogenous psychoses and in 20 normal persons. In 38% of the patients 3,4-DMPEA was found, whereas no 3,4-DMPEA was found in normal persons. When the biochemical findings obtained are correlated to the corresponding diagnoses the highest incidence of positive findings was observed in paranoid-hallucinatory schizophrenics with 71% in males and 75% in females. The signification of controls during the course of the experiments is emphasized.