Meta-analysis of Face Perception in Schizophrenia Spectrum Disorders: Evidence for Differential Impairment in Emotion Face Perception.

Background and hypothesis: Schizophrenia spectrum disorders (SSD) are associated with face perception impairments. It is unclear whether impairments are equal across aspects of face perception or larger-indicating a differential impairment-for perceiving emotions relative to other characteristics (eg, identity, age). While many studies have attempted to compare emotion and non-emotion face perception in SSD, they have varied in design and produced conflicting findings. Additionally, prior meta-analyses on this topic were not designed to disentangle differential emotion impairments from broader impairments in face perception or cognition. We hypothesize that SSD-related impairments are larger for emotion than non-emotion face perception, but study characteristics moderate this differential impairment.

Study design: We meta-analyzed 313 effect sizes from 104 articles to investigate if SSD-related impairments are significantly greater for emotion than non-emotion face perception. We tested whether key study characteristics moderated these impairments, including SSD severity, sample intelligence matching, task difficulty, and task memory dependency.

Study results: We found significantly greater impairments for emotion (Cohen's d = 0.74) than non-emotion face perception (d = 0.55) in SSD relative to control samples, regardless of SSD severity, intelligence matching, or task difficulty. Importantly, this effect was obscured when non-emotion tasks used a memory-dependent design.

Conclusions: This is the first meta-analysis to demonstrate a differential emotion impairment in SSD that cannot be explained by broader impairments in face perception or cognition. The findings also underscore the critical role of task matching in studies of face perception impairments; to prevent confounding influences from memory-dependent task designs.