Feasibility and Psychometrics of a New Test Battery for Diagnosing Patients With Schizophrenia Spectrum Disorders

Introduction Schizophrenia is a complex psychiatric disorder that is often difficult to distinguish from other psychiatric conditions, particularly in acute settings. Thought disorder and concreteness are considered distinguishing cognitive features of schizophrenia. The objective of this study was to examine the feasibility and diagnostic accuracy of a brief psychological test battery in differentiating patients with schizophrenia spectrum conditions (SSC) from control patients (C) without schizophrenia. The battery combined the Positive and Negative Syndrome Scale - Negative Subscale (PANSS-N5), the Mood Differentiation Questionnaire (MDQ), and the Pictogram Test (PT). Methods Forty patients were recruited, including 20 patients diagnosed with schizophrenia spectrum conditions (SSC) and 20 control patients (C) without schizophrenia. Participants were administered three instruments: the Positive and Negative Syndrome Scale - Negative Subscale (PANSS-N5), the Mood Differentiation Questionnaire (MDQ), and the Pictogram Test (PT). Tests were administered by medical school graduates following structured training and were scored by professionals with psychology and medical degrees. Group differences were analyzed using independent samples statistical testing. Receiver operating characteristic (ROC) curve analysis was conducted, and the area under the curve (AUC) was calculated to evaluate the classification accuracy of each instrument in distinguishing SSC from C groups. Statistical significance was set at p < 0.05. Results The Mood Differentiation Questionnaire (MDQ) did not significantly differentiate between the SSC and C groups (p > 0.05; AUC = 0.652). In contrast, both the Pictogram Test (PT) (p < 0.05; AUC = 0.761) and the Positive and Negative Syndrome Scale - Negative Subscale (PANSS-N5) (p = 0.008; AUC = 0.754) significantly discriminated between SSC and C groups. The ROC analysis demonstrated acceptable to strong classification accuracy for the PT and PANSS-N5. Conclusions This pilot study suggests that a brief psychological test battery may have potential utility in differentiating schizophrenia spectrum conditions (SSC) from non-schizophrenia psychiatric controls following brief training. However, given the small sample size and exploratory nature of the analyses, including ROC and multivariable modeling, these findings should be interpreted with caution. While preliminary results indicate moderate discriminatory performance for the Pictogram Test and PANSS-N5, further validation in larger and more diverse samples is required. Additionally, feasibility was supported by successful administration in a clinical setting, although more objective implementation metrics are needed to substantiate this finding.