Introduction: Schizophrenia-related impairments impact functional status and health-related quality of life. The Social Integration Survey (SIS) measures social functioning outcomes in schizophrenia from patient and informant perspectives.
Methods: A total of 129 patient/informant dyads at eight US sites participated. Patients were at least 18 years old, with schizophrenia or schizoaffective disorder for 1 year or more, residing in the community. Informants were at least 21 years old, cared for patient at least 1 month, with contact at least twice weekly. The SIS, PSP, PETiT, QLS, CGI-S, and PANSS were completed. Individual item performance, subscale development, reliability, and validity were examined.
Results: Items were easily understood and responses well-distributed for patients and informants. Four of five subscales identified were internally consistent (alphas >or=0.68) and stable over time. Inter-rater reliability was low. SIS scores were not strongly correlated with other measures, except PETiT Quality of Life. The SIS differentiated on social functioning at varying levels of symptom severity (P < 0.05).
Conclusions: Patient and informant-completed versions showed adequate internal consistency, test-retest reliability, and discriminant validity. Lack of correspondence between patient and informant responses and construct validity require further examination. Work-related items were inapplicable for most patients, but would be for those with higher functioning.