Intolerance of uncertainty and decision fatigue among family members of gastric cancer patients: a latent profile analysis and chain mediation model

Background Intolerance of uncertainty and decision fatigue are key negative psychological experiences for family members of gastric cancer patients when making clinical decisions; to date, few studies have simultaneously examined the relationships between family members’ intolerance of uncertainty, decision self-efficacy, perceived social support and decision fatigue. Objective This study aims to investigate the relationship between family members’ intolerance of uncertainty and decision fatigue among gastric cancer patients, to analyse the chained mediating effects of decision self-efficacy and perceived social support, and to provide a theoretical basis and practical guidance for alleviating decision fatigue among family members and safeguarding their mental health. Methods This study employed a cross-sectional design. A convenience sample of 322 family members of gastric cancer patients who were receiving inpatient treatment at the First Affiliated Hospital of Anhui Medical University in Hefei, Anhui Province, China, between December 2025 and May 2026, was recruited. Participants completed a demographic questionnaire, the Intolerance of Uncertainty Scale (IUS-12), the Decision Self-Efficacy Scale (DSES), the Perceived Social Support Scale (PSSS) and the Decision Fatigue Scale (DFS). Latent profile analysis (LPA) was used to identify subgroups based on intolerance of uncertainty, and a chained mediation model was employed to test serial mediation effects. Results Decision fatigue among family members of gastric cancer patients was positively correlated with intolerance of uncertainty, and negatively correlated with decision self-efficacy and perceived social support. Perceived social support and decision self-efficacy each independently mediated the relationship between intolerance of uncertainty and decision fatigue, accounting for 16.18% and 26.86% of the total effect, respectively; there was also a chained mediation pathway, accounting for 11.96% of the total effect. LPA identified three distinct subtypes characterised by low levels of IU (41%), moderate levels of IU (43%) and high levels of IU (16%). The mean decision fatigue scores were (16.47 ± 2.05), (17.88 ± 1.52) and (20.82 ± 3.04) for the low-, moderate-, and high-IU groups, respectively, with the high-IU group showing the highest level of decision fatigue. Conclusion Intolerance of uncertainty was indirectly associated with decision fatigue among family members of gastric cancer patients through a chained mediation relationship involving decision self-efficacy and perceived social support. Clinical healthcare professionals should recognise the heterogeneity in intolerance of uncertainty among family members of gastric cancer patients and incorporate psychological indicators, including intolerance of uncertainty, decision self-efficacy, and perceived social support, into routine psychological assessments for this population.