Early-Onset Schizophrenia: Exploring the Contribution of the Thought Disorder Index to Clinical Assessment

Resumé

Background: Differentiating diagnostically between schizophrenia and emotional and personality disorders with psychotic or psychotic-like symptoms is a challenging task. It is especially difficult when working with adolescent patients, because their symptoms tend to manifest at lower levels as compared with adult patients. Thought disorder is a core symptom of schizophrenia, and the Rorschach Inkblot Method is widely used for the assessment of formal thought disorder. Objective: In this study, which is situated within ongoing clinical practice, we investigated whether the Rorschach test is helpful for assessing early-onset schizophrenia due to its ability to detect thought disorder. We also wanted to examine whether the Thought Disorder Index (TDI) is superior to the Comprehensive System (CS) for differentiating between patients with early-onset schizophrenia and non-psychotic patients experiencing auditory and visual hallucinations. An additional aim was to examine whether the TDI correlated with the Positive and Negative Syndrome Scale (PANSS). Methods: Twenty-three subjects between the ages of 12 and 18 years were examined with the use of the Rorschach test, and the protocols were scored according to both the TDI and the CS. All subjects were also assessed with the Positive and Negative Syndrome Scale. The sample included 14 subjects who fulfilled the criteria for schizophrenia and 9 subjects who were experiencing hallucinations that emanated from severe emotional and relational problems but who had different non-psychotic disorders. Results: Although the two groups could not be distinguished with regard to their total scores for thought disorder, the identification of specific thought disorder types proved useful for differential diagnosis. Verbalizations that were categorized by the TDI as “absurd responses,” “fluidity,” “contamination,” “autistic logic,” and “word-finding difficulty” were only given by patients who had been diagnosed with schizophrenia. When patients’ responses were scored with the use of the CS, the “contamination” score was the only one found to be specific to schizophrenia. Conclusions: Although the sample size limits the conclusions that can be drawn, the results indicate that the TDI may be superior to the CS for the identification of thought disorder specific to—but not always present in—adolescents with schizophrenia. In other words, the absence of severe thought disorder is not synonymous with the absence of severe psychopathology, but the presence of the most severe thought disorder types (i.e., “absurd responses,” “fluidity,” “incoherence,” “contamination,” and “autistic logic”) seems to be a strong indicator of schizophrenic psychopathology.