BACKGROUND: Promoting social inclusion is crucial for people living with severe mental illness (SMI), who often experience high levels of social exclusion. However, research that uses a psychometric social inclusion measure to identify factors that determine varying levels of social inclusion in individuals with SMI is scarce.

AIMS: This study aimed to examine to what extent people with SMI feel socially included and to identify factors associated with perceived social inclusion among people with SMI.

METHOD: A cross-sectional multicenter investigation of psychiatric inpatients and day hospital patients with SMI aged 18 to 65 years (n = 358) was conducted. Perceived social inclusion, sociodemographic, and clinical characteristics were assessed using the Measure of Participation and Social Inclusion for Use in People with a Chronic Mental Disorder (F-INK). Hierarchical multiple linear regression was performed to analyse the association between social inclusion and potential predictors.

RESULTS: The participants' overall level of social inclusion was moderate (F-INK social inclusion total score M = 1.9, SD = 0.6). Age, relationship status, diagnostic group, employment status, and living situation emerged as predictors of social inclusion. Greater subjective social inclusion was predicted by older age (p = .027), being in a committed intimate relationship (p = .037), diagnosis of schizophrenia spectrum disorder (compared to diagnosis of depression, p = .020), being competitively employed or in education (compared to being in sheltered employment, p = .022; compared to being unemployed or receiving a disability pension, p = .007), and living with other people (p = .042).

CONCLUSIONS: The results confirm deficiencies in social inclusion of people with SMI. Individuals with SMI who are younger, single, have a diagnosis of depression, are in sheltered employment, are unemployed or receiving a disability pension, and are living alone seem to be particularly at risk of experiencing low social inclusion. These findings highlight the importance of psychosocial interventions in rehabilitative mental healthcare.