Course of depressive symptoms over time in multiple sclerosis.
|Title||Course of depressive symptoms over time in multiple sclerosis.|
|Publication Type||Journal Article|
|Authors||Johnson KL, Amtmann D, Cook KF, Bombardier CH, Salem R, McMullen KA, Molton IR|
Introduction: Research indicates a high prevalence of depression in multiple sclerosis (MS); however, its course is poorly understood. The purpose of the study was to examine depressive symptoms in MS over 28 months and to examine how baseline variables predict depression 2 years and 4 months later. Methods: Individuals with MS (n=458, 97% response rate) in Seattle, WA, USA, responded to self-report mailed surveys. Depression was assessed 7 times 4 months apart using the Patient Health Questionnaire 9 (PHQ9). Those who completed PHQ9 at least 4 times were included. Latent variable growth modeling and regression analyses were used to examine the trajectory of depression and to identify variables associated with the level of depressive symptoms. Demographic variables, general health (SF8), duration of disease, mobility, pain, fatigue, sleep, stress at baseline and the use of antidepressants at time 3 were evaluated as predictors of depression at the last time point. Results: The mean level of depression was mild and ranged from 5.4 to 8.0 across the study. The proportion of participants with moderately severe or severe depression ranged from 8% to12%. At the end of 28 months, 50% of the sample had the same level of depression as at baseline, 32% were less depressed and 18% were more depressed. The mean group trajectory was flat over time (no significant increase or decrease in the level of depression). Greater fatigue, stress, sleep problems, vision loss, side effects from medications and use of antidepressants were statistically significant predictors of higher levels of depressive symptoms at the end of the study. According to PHQ9 depression algorithm, the percentage of participants with major depressive disorder decreased over time (14.9% at time point 1 and 9.7% at the last time point). The percentage of those with significant depressive symptoms also decreased, with 34.8% at baseline and 24.3% at last follow-up. In regression analyses, lower fatigue at baseline was associated with remission of major depression at last followup. Conclusions: Results indicated that depressive symptoms fluctuated over time but group values did not change significantly. Users of antidepressants were more likely to report greater depressive symptoms. Future studies should examine long-term effectiveness of antidepressants in reducing symptoms. Effects of attrition of those experiencing the most significant symptoms needs to be addressed in longitudinal studies.