S.C. Schulz

61. Extracranial size in patients with schizophrenia

Much of the current literature from both neuroimaging and post mortem studies points to a reduction in intracranial size and cerebrum in schizophrenia. Intriguingly, there is also evidence for reduced extracranial size in infants at high risk for schizophrenia, while studies in adults with schizophrenia which have assessed head size have been inconclusive. Using head measures of circumference, length and width derived from caliper examination in both coronal and saggital planes, we examined head size in 46 male controls (mean age 42 6 9 years; 20 Caucasian, 26 African American) and 44 patients (mean age 40 6 9 years; 18 Caucasian, 26 African American) with DSM-IV schizophrenia. In a linear regression model which entered race and diagnosis as independent factors and stature and elbow breadth as covariates, we found no evidence for reduced extracranial size in schizophrenia. These data suggest that the process(es) which underlie smaller brains in schizophrenia do not produce a corresponding reduction in head size.

209. An MRI study of adolescent psychiatric patients and healthy controls

voluntarysuppressionof tics in Tourette’ssyndromeis a potentially importantmodelof impulsecontrol.UsingfunctionalMRIwestudiedtic suppressionin 22 adult subjects who had a diagnosisof Tourette’s syndrome.Wecomparedimagesacquiredduringperiodsof voluntarytic suppressionwithimagesacquiredwhensubjectsallowedthespontaneous expressionof their tics. We then correlatedthe magnitudesof signal changein the imageswithmeasuresof the severityof tic symptoms.We observedsignificantchangesin signalintensityin the basal gangliaand thalarnusand in anatornicrdlyconnectedcortical regions believed to subserveattention-demanding tasks. The magnitudesof regionsJsignal change in the basal ganglia and thalamus correlated inversely with symptomseverity.Thesefindingssuggestthat the pathogenesisof tics involves an impaired modulationof neuronal activity in subcortical neural circuits. Similarstudies of childrenwho have tic disordersare underway.

Pet study correlates of psychometric psychoticism in normals

Recent positron emission tomography (PET) studies of patients with psychosis have found decreased glucose metabolism in prefrontal cortex. We examined whether psychometric psychoticism in normals was associated with reduced glucose metabolism in prefrontal cortex in 44 males (mean age 33.27 SD 10.95) and 41 females (mean age 33.04 years SD 10.87). All subjects completed the Eysenck Personality Questionnaire (EPQ), and underwent the PET scan procedure on a Scanditronix scanner during performance of an auditory continuous performance task. ume of a control region (superior frontal gyms). An analysis of the temporal sulco-gyral pattern showed a non-parallel, discontinuous pattern in schizophrenic patients (Chi Square=l0.8, df=l, p I 0.001, phi=0.60). These findings suggest that a subset of schizophrenics show localized reductions in gray matter of the temporal lobe that are intercorrelated thus suggesting a disturbance of a neural network in schizophrenia. Moreover, degree of thought disorder was related to reduced volume of left posterior STG, an area important as a substrate of language. That the gyral pattern was also disrupted strongly implicates a neurodevelopmental disturbance may be important in the aetiology of schizophrenia.