Thomas P. Swales

A magnetic resonance imaging study of thalamic area in adolescent patients with either schizophrenia or bipolar disorder as compared to healthy controls

The purpose of this study was to compare thalamic size in adolescent patients with either schizophrenia or bipolar disorder and healthy controls. T2-weighted axial magnetic resonance images were used to manually define the area of the thalamus for 20 schizophrenia patients, 15 bipolar patients and 16 normal control subjects, all of whom were adolescents. Two orthogonal planned contrasts were tested: Contrast 1, patients with schizophrenia vs. patients with bipolar disorder; and Contrast 2, both patient groups taken as a single group compared to controls. Contrast 1 was not statistically significant for right or left thalamic area. Contrast 2 was statistically significant and indicated reductions in thalamic area in the patients as compared to controls. The same pattern of results emerged after adjustment for total brain volume. Our results indicate that thalamic abnormalities reported in adult schizophrenic and bipolar patients are also observed in adolescent patients. Our findings also add to the evidence implicating the thalamus in the pathophysiology of schizophrenia and bipolar disorder.

An MRI study of adolescent patients with either schizophrenia or bipolar disorder as compared to healthy control subjects

BACKGROUND There are few imaging studies in adolescent patients with either schizophrenia or bipolar disorder. Such studies are of interest because adolescents may have a more severe illness and neurodevelopmental events may have a greater role in their pathophysiology. METHODS We compared 20 patients with schizophrenia and 15 patients with bipolar disorder (10 to 18 years) to 16 normal adolescents on magnetic resonance imaging (MRI) measures of intracranial volume and ventricular and sulcal enlargement. Two planned comparison contrasts were employed, one comparing the two patient groups to each other (contrast 1), and one comparing both patient groups combined to control subjects (contrast 2). RESULTS None of the contrast 1 comparisons (schizophrenia vs bipolar) were statistically significant. Contrast 2 comparisons (control subjects vs patients) were statistically significant for intracranial volume (reduced in patients) as well as frontal and temporal sulcal size (increased in patients). CONCLUSIONS The patient groups were not statistically significantly different from each other on any measure. The combined patient groups were different from control subjects on intracranial volume and frontal and temporal sulcal size. Also, there was evidence for ventricular enlargement, after removal of a control subject with an extreme value. These findings indicate that the same abnormalities noted in adult populations are present in adolescents.

Adolescent Schizophrenia: A Methodologic Review of the Current Neuroimaging and Neuropsychologic Literature.

This paper reviews all relevant articles that reported structural neuroimaging or neuropsychological data in adolescent patients with schizophrenia. These papers were subsequently examined from a methodological perspective. Few papers have been written that have examined whether adolescent schizophrenia is associated with structural neuroimaging abnormalities or cognitive dysfunction. In these studies, major methodologic issues exist. Therefore, at present, firm conclusions cannot be made regarding the presence or absence of neuropsychologic dysfunction or structural neuroimaging abnormalities in this population. Attention to certain methodologic issues may improve future studies of this topic.

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.