Several studies have consistently shown that patients with schizophrenia or schizophrenia spectrum disorders (SSD) can be distinguished from normal controls on the basis of their nonverbal behavior during standardized interviews, with considerable interactions between negative symptoms and poor facial expressivity. However, most studies have examined unmedicated patients, and gender of both interviewer and interviewee has not been taken into account. In this study we assessed the nonverbal behavior of male and female patients with SSD who were receiving second-generation antipsychotic medication (SGA) using the Ethological Coding System for Interviews (Troisi, 1998). In addition, we used a novel 5-factor model of the Positive and Negative Symptom Scale (PANSS, van der Gaag et al., 2006) to correlate nonverbal behavior with standard psychopathology ratings. Our findings strongly resembled results of previous studies into nonverbal behavior of patients with SSD, despite differences in cultural backgrounds and gender of the interviewer. Negative symptoms were inversely correlated with several of the nonverbal behavioral dimensions. Medication dose did not correlate with any one of the behavioral or psychopathological measures. Patients with SSD make less use of their nonverbal behavioral repertoire compared with controls, independent of antipsychotic treatment. Culture-specific nonverbal expressivity seems to play an additional (minor) role in distinguishing patients from healthy controls
