Pattern and Predictors of Change in Depressive Symptoms Over 30 Months in MS

Background: Depression is a common symptom in relapsing-remitting multiple sclerosis (RRMS). To date, there is very little information about naturally-occurring changes in depressive symptoms over time, and even less is known about predictors of such changes in this population.

Objectives: This study examined naturally-occurring changes in depressive symptoms over a 30-month period and the associated demographic, clinical, and behavioral predictors of such change in RRMS.

Methods: The sample of 269 persons with confirmed RRMS completed the Hospital Anxiety and Depression Scale (HADS) as well as a standard demographic/clinical scale, Godin Leisure-Time Exercise Questionnaire (GLTEQ), and Patient Determined Disease Steps (PDDS) scale every 6 months over a 30 month period of time. The data were analyzed using unconditional and conditional latent growth modeling (LGM) and latent class growth modeling (LCGM) in Mplus.

Results: The unconditional LGM analyses did not indicate linear or quadratic changes in depression scores from the HADS over time. The unconditional LCGM identified a two-class model for describing linear changes in depression scores from the HADS over time. Class 1 was described by higher initial status (i.e. more depressive symptoms) and linear increases in depressive symptoms over time (i.e. worsening HADS scores), whereas Class 2 was described by lower initial status (i.e. less depressive symptoms) and linear decreases in depressive symptoms over time (i.e. improving HADS scores). Separate conditional LCGMs indicated that GLTEQ scores (physical activity), PDDS scores (disability status), and employment status predicted the two classes of HADS scores, whereas sex, age, marital status, race, education, and disease duration did not predict class membership. The final conditional LCGM with all three significant predictors indicated that physical activity and disability status, but not employment status, independently predicted the two classes of HADS scores. Those with lower GLTEQ scores and higher PDDS scores had an increased likelihood of being in Class 1 (i.e. high initial depressive symptoms that worsen over time)

Conclusions: Our results suggest that the promotion of physical activity might represent a behavioral approach for mitigating the worsening of depressive symptoms, even after considering disability status.

Disclosure: The authors report no conflicts of interest.

Funding: This research was supported by a grant from the National Multiple Sclerosis Society (RG 3926A2/1)