Charlotte Stephens, Research Correspondent, ME Association
We show below brief summaries of the research studies about ME/CFS that have been published in the last week, followed by the abstracts from those studies.
This week, 5 new research studies have been published, including a study from the University of Bristol looking at sleep problems in adolescents with ME/CFS and a study from London looking at activity levels in patients with ME/CFS in relation to their level of disability. There is also an interesting review of the various biological mechanisms thought to be involved in the pathology of ME/CFS and highlights treatment options and directions for future research.
ME/CFS Research references and abstracts
1. Anderson G and Maes M (2020)
Progress in Neuropsychopharmacological and Biological Psychiatry [Epub ahead of print].
It is widely accepted that the pathophysiology and treatment of myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) could be considerably improved. The heterogeneity of ME/CFS and the confusion over its classification have undoubtedly contributed to this, although this would seem a consequence of the complexity of the array of ME/CFS presentations and high levels of diverse comorbidities.
This article reviews the biological underpinnings of ME/CFS presentations, including the interacting roles of the gut microbiome/permeability, endogenous opioidergic system, immune cell mitochondria, autonomic nervous system, microRNA-155, viral infection/re-awakening and leptin as well as melatonin and the circadian rhythm. This details not only relevant pathophysiological processes and treatment options, but also highlights future research directions.
Due to the complexity of interacting systems in ME/CFS pathophysiology, clarification as to its biological underpinnings is likely to considerably contribute to the understanding and treatment of other complex and poorly managed conditions, including fibromyalgia, depression, migraine, and dementia. The gut and immune cell mitochondria are proposed to be two important hubs that interact with the circadian rhythm in driving ME/CFS pathophysiology.
2. King E et al. (2020)
Journal of Psychosomatic Research [Epub ahead of print].
Objectives: To classify patients with chronic fatigue syndrome (CFS) by pattern of physical activity and determine the clinical associations of each type.
Methods: 579 out of 641 participants with CFS from the PACE (Pacing, graded Activity, Cognitive behavioural therapy: a randomised Evaluation) trial wore an Actiwatch (accelerometer) for between 3 and 7 days before any trial treatments, which provided a measure of physical activity. Participants' activity was categorised into one of four patterns (pervasively inactive, pervasively active, boom and bust, or indeterminate) using a priori definitions of activity. Clinical associations were sought with each group using an exploratory binomial regression with the indeterminate activity group being the reference group.
Results: 124 (21%) of the participants were classified as pervasively inactive, 65 (11%) as pervasively active, 172 (30%) showed a ‘boom and bust’ pattern of activity, and 218 (38%) had an indeterminate pattern. Pervasively inactive patients were more physically disabled, those in the pervasively active group were more anxious, and those in the boom and bust group had more sleep disturbance.
Conclusion: We were able to classify patients with CFS into groups by their daytime activity pattern. The different patterns of activity were associated with important clinical variables, suggesting that they might be helpful in determining prognosis and targeting treatments. These associations need replication.
3. Loades ME et al. (2020)
Journal of Affective Disorders [Epub ahead of print].
Background: Co-morbid anxiety and/or depression is common in adolescents with Chronic Fatigue Syndrome (CFS/ME). Adolescents with psychopathology typically endorse more negative cognitive errors. We don't know whether they make negative cognitive errors in response to fatigue. We examined the thinking patterns of adolescents with CFS/ME and co-morbid psychopathology compared to those without this co-morbidity.
Methods: This cross-sectional study recruited 205 adolescents (age 11-18) with CFS/ME, who completed measures of anxiety and depression, information processing biases and responses to fatigue. We grouped participants as having co-morbid psychopathology (or not) by applying a threshold score. We compared groups’ thinking pattern subscale scores using independent samples T tests. We examined the association between psychopathology and general negative thinking and specific responses to fatigue symptoms.
Results: Adolescents with CFS/ME with co-morbid psychopathology more strongly endorsed general negative cognitive errors (d = 0.61-1.31). They also more strongly endorsed damage beliefs (d = 0.49), embarrassment avoidance (d = 1.05), catastrophising (d = 0.97) and symptom focusing (d = 0.75) in response to fatigue but did not differ significantly on fear avoidance from those without co-morbid psychopathology. Both negative cognitive errors and unhelpful responses to symptoms explained 43% of the variance in psychopathology.
Conclusions: Adolescents with CFS/ME with co-morbid psychopathology tend to be negatively biased in their thinking, both generally and about their symptoms of fatigue specifically. This may have implications for the sequencing of cognitive and behavioural strategies to address both fatigue and psychopathology.
4. Loades ME et al. (2020)
Clinical Child Psychology and Psychiatry [Epub ahead of print].
Sleep problems have a negative impact on a range of outcomes and are very common in adolescents with chronic fatigue syndrome (CFS). We aimed to (a) establish whether adolescents with CFS have more self-reported sleep problems than illness controls as well as healthy controls, (b) investigate changes in sleep problems and (c) explore the extent to which sleep problems at baseline predict fatigue and functioning at follow-up in adolescents with CFS.
The Insomnia Scale was completed by 121 adolescents with CFS, 78 healthy adolescents and 27 adolescents with asthma. Eighty (66%) treatment-naïve adolescents with CFS completed questionnaires approximately 3 months later. Adolescents with CFS reported increased sleep problems compared to healthy controls and adolescents with asthma. In CFS, there was no significant change in sleep problems without treatment over a 3-month follow-up. Sleep problems at baseline predicted a significant proportion of the variance in sleep problems at follow-up.
Sleep problems should be targeted in treatment. Regulating the ‘body clock' via the regulation of sleep could influence outcomes not assessed in this study such as school attainment.
5. Lubet S and Tuller D (2020)
Medical Humanities [Epub ahead of print].
In a recent article in Medical Humanities, Sharpe and Greco characterise myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) as an ‘illness without disease', citing the absence of identified diagnostic markers. They attribute patients' rejection of psychological and behavioural interventions, such as cognitive-behavioural therapy (CBT) and graded exercise therapy (GET), to a ‘paradox' resulting from a supposed failure to acknowledge that ‘there is no good objective evidence of bodily disease'.
In response, we explain that understandings about the causes of and treatments for medical complaints have shifted across centuries, and that conditions once thought to be ‘psychosomatic' have later been determined to have physiological causes. We also note that Sharpe and Greco do not disclose that leading scientists and physicians believe that ME/CFS is a biomedical disease, and that numerous experts, not just patients, have rejected the research underlying the CBT/GET treatment approach.
In conclusion, we remind investigators that medical classifications are always subject to revision based on subsequent research, and we therefore call for more humility before declaring categorically that patients are experiencing ‘illness without disease'.
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