Social deprivation in schizophrenia spectrum disorders: A systematic review

Social deprivation remains an underexplored factor in schizophrenia research, despite its well-established association with negative symptoms such as asociality and avolition. These symptoms, which impair motivation and social engagement, are often exacerbated by environmental factors like institutionalization and social isolation. This review aims to investigate the complex relationship between social deprivation (including perceived loneliness) and negative symptoms in schizophrenia spectrum disorder (SSD). We conducted a pre-registered (PROSPERO ID: CRD42022259295) systematic review searching PubMed, PsychINFO, PsyARTICLE, the Cochrane Database of Systematic Reviews, and ClinicalTrials.gov, supplemented by manual searches. Due to the heterogeneity of the studies, a meta-analysis was not conducted. Out of 2511 records screened, we included a total of 31 studies, encompassing 3 cohort, 3 randomized controlled trials, 17 cross-sectional, and 5 case-control studies published between 1995 and 2023. The majority of studies involved individuals with chronic schizophrenia spectrum disorder, although some also focused on first-episode psychosis. We analyzed both external (e.g., institutionalization, socioeconomic status, stigma, cultural context) and internal (e.g., depression, loneliness, impaired social cognition, residual positive symptoms) contributors to social deprivation and their links to negative symptoms. Findings suggest that social deprivation significantly contributes to the onset and progression of negative symptoms, ultimately reducing quality of life. This review emphasizes the need for future longitudinal studies to further explore how social deprivation impacts negative symptoms in outpatient populations, and advocates for psychosocial interventions designed to reduce social isolation, with the goal of improving patient outcomes.