Negative symptoms and sex differences in first episode schizophrenia: What's their role in the functional outcome? A longitudinal study

Introduction

Negative symptoms (NS) include asociality, avolition, anhedonia, alogia, and blunted affect and are linked to poor prognosis. It has been suggested that they reflect two different factors: diminished expression (EXP) (blunted affect and alogia) and amotivation/pleasure (MAP) (anhedonia, avolition, asociality). The aim of this article was to examine potential sex differences among first-episode schizophrenia (FES) patients and analyze sex-related predictors of two NS symptoms factors (EXP and MAP) and functional outcome.

Material and methods

Two hundred and twenty-three FES (71 females and 152 males) were included and evaluated at baseline, six-months and one-year. Repeated measures ANOVA was used to examine the effects of time and sex on NS and a multiple linear regression backward elimination was performed to predict NS factors (MAP-EXP) and functioning.

Results

Females showed fewer NS (p = 0.031; Cohen's d = −0.312), especially those related to EXP (p = 0.024; Cohen's d = −0.326) rather than MAP (p = 0.086), than males. In both male and female group, worse premorbid adjustment and higher depressive symptoms made a significant contribution to the presence of higher deficits in EXP at one-year follow-up, while positive and depressive symptoms predicted alterations in MAP. Finally, in females, lower deficits in MAP and better premorbid adjustment predicted better functioning at one-year follow-up (R² = 0.494; p < 0.001), while only higher deficits in MAP predicted worse functioning in males (R² = 0.088; p = 0.012).

Conclusions

Slightly sex differences have been found in this study. Our results lead us to consider that early interventions of NS, especially those focusing on motivation and pleasure symptoms, could improve functional outcomes.