Magnetic resonance imaging study of the cavum septi pellucidi in patients with schizophrenia.

OBJECTIVE: High-resolution magnetic resonance imaging was used to evaluate the prevalence of the cavum septi pellucidi (CSP) in 79 normal subjects and 86 patients with schizophrenia. METHOD: The CSP was assessed by counting the number of consecutive coronal 1-mm slices containing the CSP. A CSP equal to or greater than 6 mm in length was defined as large. RESULTS: The CSP was found in 74.4% of the patients and 74.7% of the normal subjects, a nonsignificant difference. No difference between groups was found in the prevalence of a large CSP. CONCLUSIONS: The findings support the idea that a small CSP is a normal anatomical variant. More cases of a large CSP are needed to elucidate the implications of this abnormality in schizophrenia.

Ventricular enlargement in schizophrenia spectrum patients with prodromal symptoms of obsessive-compulsive disorder.

We hypothesized that male patients with schizophrenia spectrum disorders who have prodromal symptoms of obsessive-compulsive disorder (OCD) have ventricular enlargement compared with non-psychotic OCD patients, and that the difference in the ventricular size would offer a clue to the early detection of schizophrenia spectrum disorders. The ventricle-brain ratios (VBRs) in eight male patients with schizophrenia or schizotypal personality disorder (SPD) who had prodromal symptoms of OCD were compared with eight male patients with non-psychotic OCD and 14 normal male comparison subjects using three-dimensional magnetic resonance imaging (MRI). The VBR of the schizophrenia spectrum group was significantly larger than those of the OCD group or comparison subjects. Even the minimum VBR in the schizophrenia spectrum group was larger than the maximum VBR in the OCD group. These results may suggest the usefulness of three-dimensional MRI for early detection of patients with schizophrenia spectrum disorders who manifest OCD symptoms early in the course of the illness.

Plasma homovanillic acid in the prodromal phase of schizophrenia.

BACKGROUND: Plasma levels of homovanillic acid (pHVA) have been used as a peripheral measure of central dopaminergic activity. Despite a large body of studies investigating pHVA in schizophrenia, little is known about pHVA in patients in the prodromal phase of the illness. METHODS: Plasma HVA levels of 12 male outpatients meeting DSM-III-R criteria for the prodromal phase of schizophrenia at the time of blood sampling (who later developed psychotic symptoms) were compared with those of 12 normal male healthy volunteers. Task amounts in the Kraepelin arithmetic test at the time of blood sampling were compared between the prodromal patients and normal controls and were correlated with pHVA levels. RESULTS: The prodromal patients had significantly higher pHVA levels compared with normal control subjects. The mean amount of the arithmetic task for the prodromal patients was significantly less than that for controls. In the patient group, a significant negative correlation was observed between pHVA levels and the task amounts. CONCLUSIONS: Data from the present study indicate the presence of dopaminergic dysfunction in the prodromal stage of schizophrenia that is associated with neuropsychological impairment. Increased pHVA levels in the prodromal patients may have implications for early detection of schizophrenia.

Differential effects of mental stress on plasma homovanillic acid in schizophrenia and normal controls.

We previously reported that mental stress by Kraepelin's arithmetic test decreases plasma homovanillic acid (pHVA) levels in psychiatrically normal healthy human subjects. The present study was undertaken to determine whether this pattern of changes in pHVA concentrations resulting from mental stress is altered in patients with schizophrenia. Fourteen male patients with schizophrenia including those under ongoing neuroleptic treatment and 14 normal male volunteers participated in the study. Following overnight fast and restricted physical activity, the subjects performed Kraepelin's arithmetic test for 30 minutes. Plasma samples were collected immediately before and after the test for measurement of pHVA levels. A significant diagnosis by Kraepelin's test effect was observed due to a decrease in pHVA levels by the Kraepelin test in control subjects but not in patients with schizophrenia. Changes in pHVA levels during the Kraepelin test positively correlated with pre-test pHVA levels in control subjects, while this correlation was not observed in patients with schizophrenia. These results may be further support for the presence of a dopamine-dependent restitutive system in the brain. The absence of response of pHVA levels to mental stress in patients with schizophrenia may indicate that the dopamine restitutive system in these patients is disrupted or already down-regulated, as previously predicted.

Effect of mental stress on plasma homovanillic acid in healthy human subjects.

Plasma levels of homovanillic acid (pHVA) have been suggested to provide a measure of dopaminergic activity in the central nervous system. The present study investigated the effect of mental stress by the Kraepelin test, a test of continuous arithmetic addition of single-digit figures for 30 min, on pHVA levels in 13 male psychiatrically normal healthy volunteers. Following an overnight fast and restricted physical activity, plasma samples were collected immediately before and after the administration of the Kraepelin test. Plasma HVA levels following the administration of the Kraepelin test were significantly lower than the pretest pHVA levels. The percent change in pHVA levels by the Kraepelin test positively correlated with pretest pHVA levels. The observed reduction in pHVA levels by mental stress in normal subjects may reflect some aspects of a dopamine-dependent restitutive system in the brain.