Self-mastery buffers associations between stressful life events and mental quality of life and fatigue in people living with multiple sclerosis

BACKGROUND: Multiple sclerosis (MS) is a chronic immune-mediated inflammatory disease of the central nervous system, often accompanied by fatigue and reduced quality of life (QoL). Stressful life events (SLEs) may heighten stress in people with MS (pwMS), compounding the challenges of living with the condition. While mastery is acknowledged as a psychological resource for resilience, its protective role against SLEs remains unclear. We examined whether mastery modifies associations between SLEs and QoL and fatigue in pwMS. METHODS: We analysed cross-sectional survey data from an international sample of 948 pwMS. Mastery (Pearlin mastery scale) was categorised into tertiles (low, moderate, high). QoL (MSQoL-54) was summarised as mental and physical composite scores. Clinically significant fatigue was defined as fatigue severity scale (FSS) > 5. SLEs exposure (Holmes-Rahe social readjustment rating scale) was assessed as total number and load (severity). Multivariable regression models assessed associations between SLEs and outcomes, and interaction terms tested effect modification by mastery. RESULTS: Higher number and load of SLEs were associated with clinically meaningful lower mental QoL (- 7 to - 8 points) among pwMS with low or moderate mastery, but not among pwMS with high mastery. Higher number and load of SLEs were also associated with 3- 5 fold higher odds of clinically significant fatigue, primarily among pwMS with low mastery. CONCLUSION: Higher mastery may buffer adverse associations between SLEs exposure and mental QoL and fatigue. Prospective studies are needed to confirm temporal relationships; however, interventions that support mastery may help mitigate stress-related impacts on wellbeing in MS.