41. THE RELATIONSHIP OF LONELINESS WITH INFLAMMATION AND HEALTH OUTCOMES ACROSS THE ADULT LIFESPAN AMONG PEOPLE LIVING WITH SCHIZOPHRENIA

Abstract

Introduction

Loneliness is distress that arises from a perceived gap between desired and actual social connections. Loneliness has negative health effects, which are particularly impactful among older adults. People living with schizophrenia (PwS) report higher rates of loneliness than non-psychiatric controls (NCs). Loneliness is associated with more severe depressive, positive, and negative symptoms, as well as worse social functioning and physical health. Furthermore, in NCs, loneliness has been linked to elevated levels of inflammatory plasma biomarkers such as IL-6, TNF-α, and CRP; however, the relationship between loneliness and inflammation in PwS remains under-explored. This study examined the association between loneliness and inflammation in PwS and NCs, as well as between loneliness and health outcomes in PwS, including symptom severity (depressive, positive, and negative), well-being, and sleep quality. The aim was to enhance our understanding of how loneliness relates to both mental and physical health in this population. Our hypotheses were: 1) PwS would have higher loneliness, inflammation, and worse health outcomes compared to NCs; 2) higher loneliness would correlate with higher inflammation in PwS and NCs; and 3) in PwS, higher loneliness would be linked to worse health outcomes.

Methods

Subsamples were utilized in this study from an overall participant pool of 111 individuals with a diagnosis with schizophrenia or schizoaffective disorder, and a non-psychiatric comparison group of 108 people with no history of serious psychiatric illness. Loneliness among participants was assessed using the UCLA Loneliness Scale, depression with the Calgary Depression Scale (CDS), positive and negative symptoms of schizophrenia with the Scales for Assessment of Positive and Negative Symptoms (SAPS and SANS), physical and mental well-being with the 36-Item Short Form Health Survey (SF-36) composite scores, and sleep quality with the Pittsburgh Sleep Quality Index (PSQI). Biomarkers (IL-6, TNF-α, hs-CRP) were assayed from fasting blood samples to assess inflammation, and biomarker data was log-transformed for normalization. Statistical analyses included T-tests, Chi-Square tests, and general linear models, with age, sex, race, and education as covariates.

Results

The final study sample for hypotheses 1 and 2 included 89 PwS and 68 NCs, of which 49% were women, and the age range was 27-76 years old. PwS had higher overall loneliness (p < 0.001, d = 0.89) and greater assayed levels of IL-6 (p = 0.002, d = 0.509), TNF-α (p = 0.005, d = 0.47), and hs-CRP (p = 0.044, d = 0.33). PwS were also more depressed and had worse physical well-being and mental well-being compared to NCs (p’s < 0.001). PwS had similar sleep quality to NCs. No relationship was found between loneliness and levels of inflammatory biomarkers for PwS or NCs.

The study sample for hypothesis 3 was pulled from the original dataset and included 73 PwS, of which 46% were women and the age range was 32-73 years old. Higher loneliness was associated with increased depression (B = 0.133, SE = 0.030, p < 0.001, ηp2 = 0.160), positive symptoms (B = 0.079, SE = 0.033, p = 0.017, ηp2 = 0.055), and negative symptoms (B = 0.070, SE = 0.027, p = 0.012, ηp2 = 0.060). Higher loneliness was associated with worse physical well-being (B = -0.208, SE = 0.083, p = 0.014, ηp2 = 0.058), mental well-being (B = -0.439, SE = 0.096, p LESS THAN 0.001, ηp2 = 0.170), and sleep quality (B = 0.079, SE = 0.031, p = 0.012, ηp2 = 0.061).

Conclusions

PwS in our study demonstrated significantly higher loneliness, baseline inflammation, depression, and worse overall well-being compared to NCs. This higher reported loneliness may reflect the unique challenges PwS face, such as limited social relationships, and living in structured environments like board and care facilities. Additionally, among PwS, loneliness was associated with worse mental and physical health. Addressing loneliness in PwS through targeted interventions could not only improve mental health outcomes but also enhance physical health and overall well-being. For the inflammatory biomarker analysis, the cross-sectional nature of our study may have limited our ability to find a relationship between loneliness and inflammation in both PwS and NCs. A longitudinal approach could better capture variations in loneliness over time and help clarify its impact on inflammatory processes. While further research is needed to explore this potential connection, reducing loneliness may present a valuable opportunity to improve quality of life in PwS.