Randall Alliger

Subcortical and temporal structures in affective disorder and schizophrenia: A magnetic resonance imaging study.

Volumetric measurements of subcortical and temporal structures were done on a sample of 54 schizophrenic patients, who were compared with 48 bipolar patients and 47 normal controls. We observed the male schizophrenic patients to have significant enlargement in the putamen and lesser enlargement in the caudate. We found the right temporal lobe to be larger than the left across all diagnostic groups, although bipolar females failed to have this asymmetry. We did not replicate the finding of decreased hippocampal, amygdala, or temporal lobe volume in our schizophrenic patients. Nor did we find significant differences between our bipolar patients and controls in the structures measured, with the exception of the right hippocampus. Our findings are consistent with a developmental defect in pruning of subcortical brain regions or with a compensatory synaptic increase secondary to decreased input from other brain regions such as the prefrontal cortex or anterior temporal lobe structures. Coupled with the lack of temporal lobe asymmetry in bipolar females, these findings suggest that different types of gender-specific neurodevelopmental abnormalities may occur in affective versus schizophrenic psychosis, which may reflect the effects of hormonal influences on brain development in predisposed individuals.

The effect of antipsychotic medication on relative cerebral blood perfusion in schizophrenia: Assessment with technetium-99m hexamethyl-propyleneamine oxime single photon emission computed tomography

Functional neuroimaging studies in schizophrenia have often been confounded by various factors including medication status. To explore the effects of antipsychotic medications on relative regional cerebral perfusion, we scanned a group of 33 persons with schizophrenia twice, while receiving a stable dose of antipsychotic and after being off antipsychotics for 3 weeks, using technetium-99m hexamethyl-propyleneamine oxime single photon emission computed tomography (Tc-99m HMPAO-SPECT. We found that antipsychotic significantly increased the mean relative cerebral perfusion in the left basal ganglia. Additionally, patients receiving thiothixene (n = 9) had a significantly greater increase in relative cerebral perfusion in the basal ganglia than patients receiving haloperidol (n = 12). These findings indicate that antipsychotics lead to regional increases in cerebral perfusion and that antipsychotic status must be controlled for in functional neuroimaging studies. Functional neuroimaging techniques such as SPECT may be useful in furthering our understanding of the mechanism of antipsychotics.

Further evidence for olfactory identification deficits in schizophrenia

Forty-seven schizophrenic patients and 36 normal controls, matched for smoking history, were administered the University of Pennsylvania Smell Identification Test (UPSIT) and the Picture Identification Test (PIT). Amongst subjects successfully completing the PIT, non-smoking schizophrenic patients had significantly lower UPSIT scores than non-smoking controls. Smoking history and diagnosis did not interact to produce any pronounced effect. No significant gender difference was found. These results suggest schizophrenics display decreased olfactory identification even if likely confounders are adequately controlled.

Positive and Negative Symptoms: Assessment and Validity

During the past decade, the study of the assessment and validity of negative symptoms has been restored to its rightful place in the realm of psychopathology. During the 1970s and early 1980s, negative symptoms were scarcely allowed in live in the servant’s quarters. Instead, they were neglected and ignored, while positive symptoms were raised to a position of pride and popularity because of their presumed superior reliability. Positive symptoms were, therefore, made the foundation of the definition of schizophrenia in the Research Diagnostic Criteria (Spitzer et al. 1978) and Diagnostic and Statistical Manual (DSM)-III (American Psychiatric Association 1980) and DSM-III-R (American Psychiatric Association 1987), and they were also given great prominence in the Present State Examination (Wing et al. 1974) and CATEGO (Wing et al. 1974). This state of affairs was in direct contradiction to the work of the historic scholars of psychopathology, Kraepelin (1919) and Bleuler (1916), who both saw negative symptoms as the core feature of schizophrenia. During the past decade, however, clinicians and investigators have returned again to this earlier perspective. Many now agree that negative symptoms (either referred to by that name or by other terms such as the apathy syndrome, the defect state, or the residual state) are the most important and the most handicapping symptoms that patients suffering from schizophrenia experience.

IQ and brain size in schizophrenia

In a previous study of normal control subjects, positive correlations were demonstrated between intelligence, as measured by the Wechsler Adult Intelligence Scale-Revised, and various measures of brain size, as assessed by magnetic resonance imaging (Andreasen et al., 1993). The goal of this study was to see if these findings generalized to schizophrenia. Corresponding analyses were performed in a group of DSM-III-R schizophrenic patients (50 men and 22 women) and compared with a subset of those normal control subjects (32 men and 27 women) who were equivalent to the patient group in their age and the educational and socioeconomic background of their families of origin. Full Scale IQ score was found to be uncorrelated with any of the regions of interest for the patient group as a whole. When subjects were divided by sex, the female patients were found to have a pattern of correlations similar to that of normal control subjects, while no such relationship was apparent among the male patients. These differences did not appear to be attributable to variability in symptom severity. Thus, there appear to be gender-related differences in brain structure/function relationships in schizophrenic patients versus normal control subjects.