Characteristics of trees drawn by patients with paranoid schizophrenia

The objective of the present study was to investigate the relationship between schizophrenia subtype and morphological characteristics of trees drawn in the Baum test. Subjects comprised the following three groups: 20 patients diagnosed with paranoid schizophrenia according to International Classification of Diseases (10th revision; ICD-10) criteria; 26 patients with non-paranoid schizophrenia according to ICD-10 criteria; and 53 healthy individuals. Differences in psychiatric symptoms as assessed using the Brief Psychiatric Rating Scale (BPRS) score were compared between patients with paranoid and non-paranoid schizophrenia. In addition, differences in two morphological characteristics of trees, namely trunk-to-crown ratio and trunk end opening, were compared between the three groups. No differences in psychiatric symptoms were identified between patients with paranoid and non-paranoid schizophrenia. Conversely, mean +/- SD trunk-to-crown ratio was 13.1 +/- 8.0 for patients with non-paranoid schizophrenia, 8.8 +/- 4.6 for patients with paranoid schizophrenia, and 5.4 +/- 3.4 for healthy individuals. Significant differences were identified between all three groups. Furthermore, mean trunk end opening was 0.80 +/- 0.7 for patients with paranoid schizophrenia, 0.38 +/- 0.6 for patients with non-paranoid schizophrenia, and 0.06 +/- 0.3 for healthy individuals. Again, significant differences were apparent between all three groups. These findings suggest that morphological differences in trees drawn in the Baum test can be observed between the two schizophrenia subtypes in terms of not only psychopathological interpretation, but also gestalt formation, as assessed on the basis of trees with collapsed gestalt or with some degree of gestalt. This suggests the possibility of multiple disorders at a physiological level. The present study confirmed that the Baum test can quantitatively assess facets of schizophrenia that existing scales such as BPRS are unable to analyze, and is useful for investigating brain function in patients with schizophrenia.