The assessment of nonverbal behavior in schizophrenia through the Formal Psychological Assessment.

The nonverbal behavior (NVB) of people diagnosed with schizophrenia consistently interacts with their symptoms during the assessment. Previous studies frequently observed such an interaction when a prevalence of negative symptoms occurred. Nonetheless, a list of NVBs linked to negative symptoms needs to be defined. Furthermore, a list of items that can exhaustively assess such NVBs is still needed. The present study aims to introduce both lists by using the Formal Psychological Assessment. A deep analysis was performed on both the scientific literature and the DSM-5 for constructing the set of nonverbal behaviors; similarly, an initial list of 138 items investigating the behaviors was obtained from instruments used to assess schizophrenia. The Formal Psychological Assessment was then applied to reduce the preliminary list. A final list of 23 items necessary and sufficient to investigate the NVBs emerged. The list also allowed us to analyze specific relations among items. The present study shows how it is possible to deepen a patient's negative symptomatology, starting with the relations between items and the NVBs they investigate. Finally, this study examines the advantages and clinical implications of defining an assessment tool based on the found list of items.