Background
Multiple Sclerosis (MS) is a multidimensional disorder with a wide range of symptoms. Some are readily apparent – for instance, changes to how a person walks or muscle weakness and tremors – while others are less so. These ‘hidden’ symptoms include pain, depression, poor sleep, and fatigue. Though less visible, these symptoms are no less a concern – 50% to 60% of people living with MS experience neurological pain, nearly 80% report extreme fatigue, and 50% experienced disrupted sleep. Roughly half of all individuals with MS will also experience depression at some point in their lives.
MS symptoms do not exist in isolation, but rather influence one another. In an effort to explore this interplay, an international team of researchers gathered data from hundreds of individuals living with MS. Their goal was twofold: first, to identify possible relationships among MS-related symptoms including physical/cognitive disability, depression, pain, sleep and fatigue. Secondly, they aimed to uncover potential risk factors influencing MS-related symptoms. Their work was published in The Clinical Journal of Pain.
The Study
424 individuals with MS, recruited from the Greater Northwest Washington chapter of the National Multiple Sclerosis Society, took part in the study. All participants completed a detailed questionnaire. Questions ranged from the participants’ gender, age, and level of education, to the presence and severity of general MS symptoms. The category “general symptoms” measured the decline in physical, sensory (vision and speech), and cognitive (learning and memory) capabilities. Participants also reported levels of pain, depression, and fatigue, as well as sleep quality and pain interference. Pain interference is a measure of pain’s impact on someone’s day-to-day life, such as forcing a change in activities or missing work.
The data was analyzed for possible relationships between symptoms. For example, the authors asked questions like: were older participants, or those who had lived with MS for long periods of time, more likely to suffer from pain or fatigue? Were MS-related symptoms more closely linked to a person’s socioeconomic status?
Results
The authors found that the presence and severity of physical, sensory and cognitive MS symptoms could predict the appearance of pain, depression and fatigue – the worse a participant’s general MS symptoms, the more likely they were to suffer from pain, depression, and fatigue.
With depression, participants reported having poor sleep quality and increased amounts of fatigue.
In contrast, physical pain was minimally associated with depression, sleep quality, and fatigue. However, those living with pain or depression were more likely to experience pain interference on a daily basis.
The team also identified two potential risk factors affecting MS-related symptoms; participant education and relationship status. Participants with lower levels of education were more likely to have greater pain intensity, to experience more severe general MS symptoms, and to suffer from depression. Those without a committed/marital relationship were more likely to experience pain and depression, both outcomes that interfered with the participant’s ability to partake in daily life.
The authors found no link between pain intensity and the duration of the disorder, nor between pain and the participant’s age or gender.
Comment
This study highlights the interactions between a variety of physical and psychological symptoms experienced by those with MS. Dr. Jensen and his team found that “hidden” symptoms – pain, depression, sleep impairment, and fatigue – can perpetuate a vicious cycle that leads to progressively worse outcomes. The authors stressed the need for health care providers to take these symptoms into consideration when discussing MS treatment plans. Depression, in particular, was of interest to the researchers, as it influenced nearly all other measured outcomes, including sleep, fatigue, and pain interference. Dr. Jensen and his team suggested that more work is needed to determine the extent to which treating depression would improve physical and psychological well-being in MS.
Also emerging from the study were two social risk factors linked to worsening pain intensity and depression in MS; education and relationship status. Although the reason for this relationship is still unclear, the authors advocated for clinical guidelines to identify at-risk individuals and to assist physicians in optimizing MS treatments for those at-risk.
Source
Day MA et al. (2016). An empirical investigation of a biopsychosocial model of pain in multiple sclerosis. Clinical Journal of Pain. 32(2): 155-63.