Social isolation and cognitive function in patients with schizophrenia: A two years follow-up study

Cognitive impairment is a core characteristic of schizophrenia. Social isolation has been linked to impaired cognitive function among the general population. In this longitudinal study, we examined the association between social isolation and cognitive function among inpatients with schizophrenia. Two waves of data (2019 and 2021) were collected from chronic psychiatric wards. A total of 166 inpatients completed all measurements at baseline and follow-up. Social isolation was measured by incorporating the frequency of social contact and participation, while cognitive functions were assessed by the Taiwan version of the Montreal Cognitive Assessment (MoCA-T). We used multiple linear regression to evaluate the link between baseline social isolation and cognitive function. For the total sample, social isolation was significantly related to poor language abilities (β = -0.17, p = 0.013) and delayed recall (β = -0.15, p = 0.023). Sex-stratified analysis showed that social isolation was significantly related to poor global cognitive function (β = -0.14, p = 0.021) and domain-specific cognitive functions including language abilities (β = -0.26, p = 0.003) and delayed recall (β = -0.19, p = 0.045) in male inpatients. No significant association was found between social isolation and global cognitive function or any cognitive domain (all ps > 0.05) for females. All associations were independent of loneliness and other covariates. These findings suggested that social isolation could predict poor subsequent cognitive function in inpatients with schizophrenia, especially in males. Interventions aimed at enhancing social connections could potentially improve cognitive function in this population.