Objective: Lateral ventricle enlargement in schizophrenia has been positively correlated with poor premorbid competence, negative symptoms, and poor treatment response and negatively correlated with concentrations of homovanillic acid (HVA), a dopaminergic metabolite. The authors provide further evidence of a reciprocal relationship between lateral ventricle size and dopaminergic activity in schizophrenia.
Method: They assessed the relationship between lateral ventricle enlargement (ventricle-brain ratio, VBR) and CSF neurotransmitter metabolite concentrations (HVA and 5-hydroxyindoleacetic acid [5-HIAA]) in 45 patients with schizophrenia, 28 with affective disorders (19 patients with major depression and nine with bipolar disorder), and 91 normal comparison subjects.
Results: No group mean differences were significant. Although individual correlations of VBR with HVA and 5-HIAA were not statistically significant, the ratio of HVA to 5-HIAA was significantly correlated with VBR in the patients with schizophrenia, a finding consistent with dopaminergic-serotonergic balance hypotheses.
Conclusions: These data suggest that it is the balance between HVA and 5-HIAA rather than their absolute levels which is associated with brain morphology and that this relationship between brain chemistry and morphology may be characteristic of the normal range of functioning for these systems. In other words, independent of whether brain morphology and chemistry differentiate psychopathological from nonpsychopathological states, there may be an orderly relationship between lateral ventricle size and the balance between HVA and 5-HIAA balance that is especially prominent in schizophrenia.