Third ventricular width and its relationship to mode of onset of schizophrenia

The mode of onset of schizophrenia (i.e., insidious versus acute) may be of neurobiologic and prognostic significance. Schizophrenic symptoms which appear acutely are believed to signify a more benign developmental course and a more favorable outcome of illness than symptoms which emerge insidiously. Since third ventricular enlargement may be a neuroradiological marker of negative schizophrenia, a subgroup of schizophrenia which is associated with poor premorbid adjustment and prognosis, I predict that it will be associated also with an insidious development of disease. To empirically test this hypothesis, I investigated in 22 institutionalized chronic schizophrenic patients (20 men, 2 women; mean age = 31.9 years, SD = 7.1), the association between the mode of onset of schizophrenia and third ventricular width (TVW) on CT scan. In the sample, 15 patients (68.2%) experienced an insidious onset of schizophrenia while 7 patients had a more sudden onset. The two cohorts did not differ significantly on any of the demographic, historic, cognitive, psychopathological, and treatment variables surveyed with the exception of duration of formal education which was significantly shorter in patients with an insidious onset of illness. However, patients with an insidious onset had a significantly greater TVW as compared to those with a sudden onset (M = 7.7 +/- 3.0 mm vs. 4.6 +/- 3.6 mm, p < .05, two-tailed). These findings demonstrate an association between the mode of onset of schizophrenia and TVW on CT scan and suggest that an insult to peri-third ventricular structures, which may underlie third ventricular enlargement, is associated with an insidious development of schizophrenia.