The link between early depression and disability in multiple sclerosis
A new study published in Scientific Reports1 examines the relationship between early depressive symptoms and disability accrual in people with multiple sclerosis (MS).
The study aims to understand the factors that influence the long-term disability outcomes in MS, which is a chronic neurological condition that affects millions of people worldwide. MS causes inflammation and damage to the protective coating of nerve fibers, leading to various symptoms such as vision problems, fatigue, pain, and mobility issues.
One of the challenges in MS research is to identify the predictors of disability progression, which varies widely among individuals. Previous studies have suggested a link between depression and disability in MS, but the direction and causality of this association are unclear.
Depression is a common psychiatric comorbidity in MS, affecting up to 50% of patients at some point. Depression can have a negative impact on the quality of life, adherence to treatment, and cognitive function of people with MS. However, it is also possible that depression is a consequence of disability, rather than a cause.
The researchers used data from the UK MS Register (UKMSR), which is a large online platform that collects information from people with MS across the UK. They analyzed data from 862 people with MS who completed online questionnaires about their symptoms, disability level, and quality of life.
The researchers measured depressive symptoms using the Hospital Anxiety and Depression Scale (HADS), which is a widely used screening tool for anxiety and depression. They measured disability level using the Expanded Disability Status Scale (EDSS), which is a standard scale for assessing physical impairment in MS.
The researchers followed up the participants for an average of 3.5 years and recorded their EDSS scores over time. They used statistical methods to evaluate whether early depressive symptoms predicted subsequent disability worsening, defined as reaching an EDSS score of 6.0 or higher. This score indicates that a person needs assistance to walk.
The results showed that early depressive symptoms were associated with an increased risk of reaching an EDSS score of 6.0 or higher. However, this effect disappeared when adjusting for baseline EDSS score, which means that early depressive symptoms did not predict disability worsening independently of initial disability level.
The researchers concluded that their study suggests that early depressive symptoms in MS are associated with subsequent disability accrual, but are likely the result of disability rather than its cause. They suggested that treating depression in MS may improve quality of life, but may not prevent disability progression.
Why is this study important?
MS is a major cause of neurological disability among young adults, affecting their physical, mental, and social well-being. Understanding the factors that influence disability progression in MS is important for developing effective interventions and improving prognosis.
Depression is a common and serious condition that affects many people with MS. Depression can have a negative impact on various aspects of life, such as mood, cognition, motivation, and social relationships. Depression can also affect adherence to treatment and participation in rehabilitation programs.
Previous studies have suggested a link between depression and disability in MS, but the nature and direction of this link are unclear. Some studies have suggested that depression may contribute to disability progression by affecting immune function, inflammation, or neurodegeneration. Other studies have suggested that depression may be a consequence of disability progression by affecting coping skills, self-esteem, or social support.
The study by Jacobs et al. is one of the first to examine the relationship between early depressive symptoms and disability accrual in MS using data from a large online platform. The study provides evidence that early depressive symptoms are associated with subsequent disability accrual, but are likely the result of disability rather than its cause.
What are the limitations and future directions?
The study by Jacobs et al. has some limitations that need to be addressed in future research. First, the study used self-reported measures of depressive symptoms and disability level, which may be subject to bias or error. It is possible that some participants may have underreported or overreported their symptoms or impairment due to social desirability or recall bias.
Second, the study did not measure other factors that may influence disability progression in MS, such as genetic factors, environmental factors, comorbidities, or treatment history. It is possible that these factors may confound or mediate the relationship between depression and disability in MS.
Third, the study did not investigate the mechanisms or pathways involved in depression and disability in MS. It is possible that there may be biological or psychological processes that link depression and disability in MS, such as inflammation, neurodegeneration, coping skills, or resilience.
Finally, the study did not test the effectiveness or safety of interventions for depression in MS. It is possible that treating depression in MS may have beneficial effects on other outcomes besides disability progression, such as quality of life, cognitive function, or social relationships.
1: Jacobs BM, Daruwalla C, McKeon MO, et al. Early depressive symptoms and disability accrual in Multiple Sclerosis: a UK MS Register study. Sci Rep. 2023;13(1):8227. doi:10.1038/s41598-023-34545-6