Physical, Mental, and Social Characteristics Associated With Happiness in Individuals With Schizophrenia in Japan: A Cross-Sectional Study

Objective: To examine the characteristics associated with happiness in Japanese individuals with schizophrenia. Methods: A self-reported online survey was conducted in 2022 among individuals aged 20–75 years, including 223 and 1776 individuals with and without schizophrenia, respectively. We used a modified Poisson regression to assess the factors associated with happiness by calculating the age- and sex-adjusted prevalence ratios (PRs). We examined within-schizophrenia group differences by age and sex strata, and compared these stratified PRs between groups with and without schizophrenia. Results: Among participants with schizophrenia, happiness was significantly associated with self-rated health status (PR = 1.75), Ikigai (PR = 5.02), depressive symptoms (PR = 0.43), perceived stress (PR = 0.52), cognitive social capital (PR = 2.07), structural social capital (PR = 1.70), social support (PR = 2.40), close friends (PR = 1.88), close relatives (PR = 2.34), and a cohabiting partner (PR = 1.57). Within the schizophrenia group, sex differences were significant for cognitive social capital (men: PR = 3.45; women: PR = 1.43) and cohabiting partners (men: PR = 2.26; women: PR = 1.25), whereas no significant age differences were found. Factors demonstrating a stronger association in participants with schizophrenia than in those without schizophrenia included: Ikigai (with, PR = 5.02; without, PR = 2.91), cognitive social capital (with, PR = 2.07; without, PR = 1.49), and structural social capital (with, PR = 1.70; without, PR = 1.24). Conclusion: Happiness in individuals with schizophrenia is associated with physical, mental, and social factors, with social factors exhibiting sex-related differences.