Background
This paper provides a brief literature review concerning the relationship between physiological difficulties associated with Multiple Sclerosis (MS) and psychological interventions intended to remediate or otherwise improve functionality and quality of life. Our specific focus is the unearthing of evidence that psychological or behavioral treatments have an impact on both the psychological well-being and the physiological consequences of the disease. We are also interested in exploring the relationship between MS symptoms and psychological issues within the broader framework of the mind-body connection. The paper summarizes the structure of this framework along with the trends in the literature; presents the etiology and primary physiological consequences of MS; a summary of its psychological consequences investigated thus far; and an application of the mind/body hypothesis in the MS field. We identify some key gaps in related research and propose potential areas for further work to address these gaps.
Consciousness and the Brain: The Mind-body Connection
The classic mind-body problem searches for an understanding of the distinctions – or lack thereof – between physical and mental entities: Is the physical brain a distinct entity from its mental processes? How do we know, how is it defined, and what implications are there for how we understand and treat our health?
Conceptions of a dualistic framework follow the early work of Descartes who proposed that the mind is a nonphysical substance distinct from the brain, that our mind (and all it encompasses) is different from our physical brain in its fundamental composition as matter. In contrast to that is the argument for materialism proposing that because the world consists only of matter, there is no true distinction between the mental and the physical, i.e., that all mental states, properties, and processes are connected and interact with physical states, properties, and processes. Much of Western culture continues to preserve a belief in the dichotomy between mind and body.
We see dualism in medical science, which maintains the notion that disorders stem from either the physical or the mental, treating the mind and the body separately. Although there was an appeal that from the field of psychiatry is now beginning to extend over different medical specialties for a more comprehensive treatment model (i.e., a bio-psycho-social approach), a strictly biomedical approach to physical illnesses persists, treating physical bodily symptoms to the exclusion of mental health. Findings from more current research suggest that is changing in several areas, proposing correlations between consciousness and the brain; that negative emotions (e.g., depression and anxiety) are highly associated with the development of coronary heart disease; and that such emotions have a negative effect on cardiovascular and immune system responses. Further research suggests that negative emotions can produce direct and indirect influence on state and trait pain and fatigue. Similarly, Pressman and Cohen suggest that positive emotions can lead to an improvement in physical health, such as increased physical functioning in adults, protection against infectious illness, and lower mortality rates.
The link between mind and body has been proposed going back as far as the 1970s, when Ellen Langer conducted one of the first tests of the mind/body unity theory on disease and ageing. Langer suggested that a healthy mind would put the body in a healthier place, forming the basis for the 1980 "counterclockwise study", in which Langer and her students studied what effects of turning back the clock psychologically would have on the physiological states of the participants. The results of this study changed the way we view not only aging (the cohort being elderly men) but also of traditional western notions of "limits" - that biology is not destiny, that "it is not primarily our physical selves that limit us but rather our mindset about our physical limits".
Physiology and Key Psychological Consequences of Multiple Sclerosis
Multiple Sclerosis is a chronic degenerative disease of the central nervous system that involves functionality of the brain and spinal cord, with physical, sensory, cognitive and emotional responses ranging from mild to severe. The relatively high variability in symptomology is determined primarily by the location of the lesions in the brain and spinal cord. Lesions in the frontal and parietal lobes result in cognitive and emotional problems; plaque in the cerebrum, brain stem and spinal cord result in functional limitations of extremities. In this sense, MS is a highly individual disease, prompting interventions targeting broad categories of disease progression and psychosocial impacts. The National Multiple Sclerosis Society (NMSS) estimates prevalence of MS in the United States at 400,000, and global prevalence at over 2 million people.
A diagnosis of MS often has profound social and psychological consequences. Because MS usually strikes individuals in their most productive years, its impact can be overwhelming. The unpredictable and variable nature of MS also makes it particularly difficult to accept. The newly diagnosed individual is faced first with the shock of a disease, which is chronic and unpredictable in its course, often with progressive impacts on critical spheres of functioning. The future undoubtedly promises reduced physical function and disability, along with disruptions in education, employment, sexual and family functioning, friendships and activities of daily living. The grim prognosis and the added unpredictability of day-to-day health in relapse-remitting MS and side effects of medication greatly impacts upon quality of life.
Multiple Sclerosis can also have a considerable influence on the individual's sense of self. Physical changes and functional limitations may lead to a sense of loss of identity or role strain especially when the individual can no longer perform previously valued activities. It is frequently necessary to redefine one's self-image in order to incorporate the limitations imposed by MS. Each time the individual experiences a new loss of function this sense of loss may be renewed. One of the major sources of psychological distress related to the physical impairments is sexual dysfunction. The most frequent complaints are erectile and ejaculatory dysfunctions in men, vaginal lubrication in women, and a loss of libido and difficulty in achieving orgasm in both genders. This problem covers significant aspects of life and can arise at any time during the course of MS, with a prevalence that varies between 50% and 90%.
Depressive features are often reported by people who have MS. Lifetime prevalence of major depressive disorder (MDD) is approximately 50%. This is three times the rate reported in the general population; the high prevalence may have multiple etiologies, including psychosocial factors such as the difficulty to deal with one's emotions, and lack of social support. Depression is one of the main determinants of quality of life and may further compromise cognitive function, and may lead to suicidal intent. It often impairs relationships and reduces compliance with disease- modifying treatments. In addition, people with MS and MDD have been found to suffer from high levels of anxiety.
Relationship Between Physiological and Psychological Features in Multiple Sclerosis
Depressive features following the onset of MS physiological symptoms may not be a simple psychological reaction to MS, but instead may be related to biological aspects of the illness itself. Biological processes such as inflammation, neuroendocrine dysfunction or regional brain damage are likely to be at least partly responsible for depressive features.
The relationship between psychological issues and MS symptoms has been underestimated in the past, but there is growing evidence of increased interest within the scientific community. For example, a number of prospective studies suggest that psychological stress increases relapse risk in MS. We believe that more focused investigations into the physiological outcomes of a psychological intervention may lead to a better understanding of therapeutic options for people with MS.
It is also possible that the relationship between the underlying biological mechanism of MS and depressive symptoms works in two directions. If that is the case, successful treatment of depression utilizing behavioral approaches could also affect the underlying MS physiology, encouraging consideration of psychological interventions that could reduce the symptomatology of the illness and moving from a palliative care framework for behavioral treatments to a potentially therapeutic one. There is little direct evidence for this hypothesis currently, primarily because behavioral interventions rarely include biological markers or even consider symptoms assessment among the outcomes. Thus far, psychological outcomes are most often the only ones expected and assessed at the end of a behavioral treatment, without considering the possibility that an intervention could impact physiological measures.