Understanding others as a mediator between verbal memory and negative symptoms in schizophrenia-spectrum disorder

From the onset of schizophrenia, verbal memory (VM) deficits and negative symptoms are strongly associated, and both additively predict functional outcomes. Emotion recognition (ER) and theory of mind (ToM; the ability to infer others' mental states), two components of social cognition, are also particularly affected in schizophrenia. Explanatory models of negative symptoms have integrated these cognitive impairments as potential precursors and previous studies revealed relationships between ER and/or ToM and VM, as well as with negative symptoms, but the organization of these associations remains unclear. We aimed to determine whether impairments in VM and social cognition sequentially pave the way for negative symptoms in schizophrenia. To this end, we used mediation analyses. One hundred and forty participants with a diagnosis of schizophrenia or schizoaffective disorder were recruited. First, correlational analyses were conducted between our variables of interest. The mediating effect of social cognition between VM and negative symptoms was then examined using the PROCESS macro. Variables of interest were significantly correlated (r = |0.166| to |0.391|), except for ER and negative symptoms. Only the serial multiple mediation model with 2 mediators (ER followed by ToM) revealed a significant indirect effect of VM on negative symptoms (β = - 0.160, 95% CI = -.370 to -.004). This relationship was selective for expressive negative symptoms (e.g., blunted affect and alogia). This study illustrates the richness of the relationship between cognitive deficits and negative symptoms and provides additional information for the involvement of social cognition in negative symptoms' etiology.