Choice of Comparison Group and Findings of Computerised Tomography in Schizophrenia

Abstract

The literature indicates that whether or not schizophrenic patients are reported to have significant lateral ventricular enlargement depends on control, and not schizophrenic-group values. This discrepancy does not result from differences in age, the ratio of males to females, the number of control subjects used in each study, or whether control groups are comprised of normal subjects or medical patients. However, medical-patient controls tend to have smaller ventricles than do normal individuals. Thus, we assessed lateral- and third-ventricle size and the degree of cortical atrophy in 30 normal volunteers, 30 medical patients, and 30 chronic schizophrenic patients. The use of a medical control group seemed to result in underestimates of ventricle and sulcal size in the normal population and, therefore, overestimates of these values in schizophrenic groups.

Endophenotypes in schizophrenia: A selective review

“…In addition, there is a possibility that healthy controls, usually volunteers, were not stringently screened for psychiatric illnesses or family psychiatry psychiatric history, leading to a potential confound in terms of the prevalence of these endophenotypes in the general population. In fact, these “healthy controls” may not be fair representatives of the general population, as discussed elsewhere (Raz et al, 1988; Schwartz and Link, 1989; Shtasel et al, 1991); Smith et al, 1988). In the studies that we reviewed, only a little over half used a structured clinical interview (e.g.…”

An Update on the Epidemiology of Schizophrenia*

“…The WHO investigators looked for cases not only within the mental health system, but in all settings in which persons suffering from schizophrenia might appear in the early phases of their illness (for example, medical treatment settings, religious agencies, social welfare offices, jails) (9). The Ireland study (37) and the DBC Markers and Predictors of Schizophrenia project (MAP) also used this technique in their search for cases (32,(38)(39)(40)(41)(42)(43).…”

A comprehensive method of assessing routine CT scans in schizophrenia

“…Lateral ventricles were planimetrically measured, third ventricle width was measured, and a global rating of cortical sulcal dilation was made using a three-point scale. The inter-rater reliability was high for all three measures (11). Third ventricle size was larger in patients with schizophrenia than in control subjects, but no group differences were found for the ventricle to brain ratio (VBR) or cortical rating.…”

“…Sample 1-The first sample (see Table 1) was scanned between 1983 and 1986 as part of a study of first-episode schizophrenia (10,11). CT scans were obtained using a Siemens Somatom DR scanner with a slice thickness of 8 mm and no contrast medium, and care was taken to prevent significant lateral head tilt.…”

“…Inter-method agreement-All subjects from sample 1 were used to compare ratings of the lateral ventricles with the measure of ventricular area and VBR, the rating of third ventricle size to third ventricle width, and ratings of cortical sulci to the original global three-point rating (11). The 40 subjects from sample 2 were used to compare CTRSS ratings with measures of volume from nine brain regions.…”