Negative symptom configuration within and outside schizophrenia spectrum disorders: results from the “Parma Early Psychosis” program.

The identification of discrete dimensions underlining negative symptoms in First Episode Psychosis (FEP) may be useful in the treatment strategy for such severe symptomatology. Aim of this research was to investigate the negative symptom configuration in FEP patients and to compare the emerging factor solutions between individuals with and without Schizophrenia Spectrum Disorders (non-SSD vs SSD). Two-hundred-seventy-four participants (144 non-SSD and 130 SSD), aged 13-35 years, completed the Positive and Negative Syndrome Scale (PANSS) and the Global Assessment of Functioning (GAF). Confirmatory and exploratory factor analyses were then performed to examine PANSS negative symptom configuration in both SSD and non-SSD samples. In SSD, a 3-factor model solution (i.e. “Experiential Deficits”, “Volition/Empathy Deficits” and “Motor/Affective Expression Deficits” domains) was identified. A different 2-factor configuration (with “Social/Communicative Withdrawal” and “Motor/Affective/Motivational Deficits” dimensions) was more appropriate in non-SSD. In conclusion, our results show differences in negative symptom factor models between non-SSD and SSD. Thus, a different specificity and significance of negative symptom solutions in FEP populations with diagnoses other than schizophrenia (compared to those with SSD) must be realistically considered.