Objective: To examine the relative association between daily change in pain, fatigue, depressed mood, and cognitive function and 4 outcomes-positive affect and well-being, ability to participate in social roles and activities, upper extremity (UE) functioning, and lower extremity (LE) functioning.

Design: Data analysis, multilevel mixed modeling.

Setting: General community.

Participants: Ambulatory adults (N=102) with multiple sclerosis.

Interventions: Not applicable.

Main outcome measures: Customized short-forms of the Quality of Life in Neurological Disorders positive affect and well-being, UE functioning, and LE functioning item banks and the Patient-Reported Outcomes Measurement Information System ability to participate in social roles and activities item bank adapted for daily use and administered as end-of-day diaries.

Results: Above and beyond the effects of demographic and clinical covariates, daily pain was associated with 3 of the 4 outcomes; days of higher than usual pain were related to lower same-day social participation (unstandardized β, B=-1.00; P=.002), UE functioning (B=-1.04; P=.01), and LE functioning (B=-.71; P=.04). Daily fatigue and depressed mood were independently related to daily positive affect and well-being; days of worse fatigue (B=-.54; P=.006) and depressed mood (B=-1.17; P<.0001) were related to lower same-day well-being.

Conclusions: The results indicate the role of fluctuations in symptoms in daily functioning and quality of life of individuals with multiple sclerosis. Daily increases in pain intensity are related to social and physical functioning, whereas increases in fatigue and depressed mood are related to lower daily well-being. Findings implicate a person-centered approach to monitoring and treating symptoms.