Exploring depression in people with schizophrenia spectrum disorders: A cross-sectional analysis of the clinical relationship with Positive and Negative Syndrome Scale dimensions

Objective: Evidence on the relationship of depression with clinical dimensions of schizophrenia remains limited. This cross-sectional study aimed at exploring the association of depression with the Positive and Negative Syndrome Scale (PANSS) dimensions in people with schizophrenia spectrum disorders (SSD). Methods: Trained assessors administered PANSS to measure core symptoms of schizophrenia and the Calgary Depression Scale for Schizophrenia (CDSS) to measure depressive features. Multiple logistic regression analyses were carried out to analyse the association of depression with PANSS overall score and related dimensions. Results: We included 231 inpatients with SSD (mean age:42.4±12.9 years; males: 58.9%; mean PANSS overall score:82.5±20.1; drug-free or naïve: 39.3%), including 78 (33.8%) with clinically significant depressive symptoms. Depression was associated with higher overall (regression coefficient [coeff.], standard error [SE]: 0.029, 0.008; p<0.001) and General Psychopathology (coeff., SE: 0.118, 0.023; p<0.001) PANSS scores. We found an inverse relationship between depression and positive symptoms (coeff., SE: -0.088, 0.028; p=0.002). No association between depressive and negative symptoms was estimated. Conclusions: Despite some limitations, our study shows that people affected by SSD with depressive features are likely to show more overall and general psychopathology symptoms, though lower positive symptoms. Additional studies are needed to explore the generalizability of our findings.