Chronic fatigue syndrome treatment
Treatment of chronic fatigue syndrome (CFS) is variable and uncertain, and the condition is primarily managed rather than cured. Only two treatments, cognitive behavioral therapy and graded exercise therapy, have demonstrated reproducible evidence for their efficacy in ambulant (non-severely affected) patients. Other proposed treatments include medications, medical treatments, and alternative medicine. Even when treated, the prognosis of CFS is often poor. In one study, poor early management was reported to be a main risk factor for severe CFS (delayed diagnosis, poor response to analgesics, physiotherapy, or alternative medicine), with associated variables including a poor relationship with the GP before and after diagnosis, and the involvement of a psychiatrist in initial treatment.
- 1 Management techniques
- 2 Antiviral Treatments
- 3 Pharmacological treatments
- 4 Alternative medicine
- 5 Placebo response
- 6 Recovery
- 7 References
CFS management techniques include behavioral interventions such as cognitive behavioral therapy (CBT, a form of psychological therapy), and graded exercise therapy (GET). Based on evidence from multiple randomized clinical trials (RCTs), a systematic review published in the Journal of the Royal Society of Medicine (October 2006) stated that CBT and GET interventions showed promising results, appearing to reduce symptoms and improve function. The review stated that the evidence of effectiveness was inconclusive for most other interventions, with some reporting significant adverse effects. The wide variety of outcome measures used in CFS research was found to be a "fundamental problem" for assessing the effectiveness of interventions in general, and no intervention has proven to be effective in restoring the ability to work.
Recovery is "rare" even after a comprehensive rehabilitation programme.
Cognitive behavioral therapy
According to the cognitive-behavioural model of illness, the patient's interpretation of symptoms plays an important role in shaping their behaviour and perpetuating the illness. There are two main cognitive-behavioural hypotheses for CFS. The first hypothesis assumes that CFS is perpetuated by the patient's cognitions, behaviour and emotions, and attempts to reverse patients symptoms to a more normal condition in a structured program. The second hypothesis assumes that CBT can help the patient cope with their disability by better management of rest and activity within the boundaries of the energy constraints of the disorder, and does not actively attempt to improve the patient’s physical or psychological capacity.
The first trial finding the efficacy of CBT for CFS was published in 1996 by Sharpe and colleagues in Oxford. More recently a systematic review of RCTs found that there is moderate evidence of benefit for CBT in CFS, but that the effectiveness of CBT for CFS outside of specialist settings has been questioned and the quality of the evidence is low. A 2008 Cochrane review of CBT concluded, "CBT is more effective than usual care for reducing fatigue symptoms in adults with CFS, with 40% of participants assigned to CBT showing clinical response at post-treatment, in comparison with 26% assigned to usual care control.", however, it also stated that the benefits of CBT in sustaining clinical response at follow up are inconclusive, and there were no conclusive improvements to physical functioning, depression, anxiety or psychological distress at either post treatment or later follow-up. Data on adverse effects were not systematically presented by any included study. The review also concluded that while the quantity and quality of the evidence has grown in recent years "there is a surprising lack of high quality evidence on the effectiveness of CBT alone or in combination with other treatments to inform the development of clinical management programmes for people with CFS".
Another systematic review on CBT finds that "CBT was associated with a significant positive effect on fatigue, symptoms, physical functioning and school attendance.", but had not proved to be effective in restoring the ability to work. The reviewers state that the quality of many recent trials on CBT are lower quality randomized controlled trials or trials that did not involve random allocation. The reviewers also state that one recent, good quality trial of CBT in children and adolescence supports the effectiveness of CBT. The reviewers state that reasons for withdrawals typically remain unreported, and that a degree of publication bias seems to be present in CFS/ME literature as a whole. In one study, the effect of CBT has been demonstrated up to five years after therapy.
A 2007 meta-analysis found that the effectiveness of CBT depends on the diagnostic criteria used, with studies using the Oxford criteria having a trend towards significantly higher effect sizes that those using the CDC criteria. The review also notes that CBT for chronic fatigue disorders has about the same efficacy as diverse psychological treatments for a variety of psychological disorders.
A 2010 meta-analysis of trials that objectively measured physical activity before and after CBT showed that although CBT effectively reduced patients' fatigue questionnaire scores, activity levels were not improved by CBT and changes in physical activity were not related to changes in fatigue questionnaire scores. They conclude that the effect of CBT on fatigue questionnaire scores is not mediated by a change in physical activity. According to the authors of a 2014 systematic review, the lack of changes to objectively measured physical activity contradict the cognitive behavioural model of CFS and suggest that patients still avoided postexertional symptom exacerbations and adapted to the illness rather than recovered from it.
According to a 2006 systematic review, "very few studies have assessed the effectiveness of interventions for children and young people and for severely affected patients. The effectiveness of CBT for adolescents is supported by a recent high-quality RCT, although this had only 69 participants." Currently there is no research into the effectiveness of CBT for the severely affected, and these patients may be effectively excluded from trials due to the need to attend a clinic. Some CBT trials suffer from large dropout rates, up to 42% in one study, with a mean dropout rate of 16%. This compares to a 17% dropout rate in a trial of 432 patients receiving CBT for anxiety, "so is not unusually high" according to a 2007 meta-analysis.
A 2011 meta-analysis concluded that both CBT and GET are both equally efficacious treatments for CFS, but that CBT may be a more effective treatment when patients have comorbid anxiety or depression.
CBT has been criticised by patients' organisations because of negative reports from some of their members which have indicated that CBT can sometimes make people worse, a common result across multiple patient surveys. One such survey conducted by Action for ME in 2001 found that out of the 285 participants who reported using CBT, 7% reported it to be helpful, 67% reported no change, and 26% reported that it made their condition worse. A subsequent survey in 2008 reported that 50% of patients found CBT helpful, 38% reported no change, and 12% felt that it made their illness worse, though it remained among the lowest-rated treatments in the survey despite the significant increase.
A systematic study conducted at the behest of the Belgian government of over 800 CFS patients treated in four reference centers which tested CBT and GET in a clinical setting concluded that although patient motivation for treatment seemed to be high and that in 71% the supervising team considered the patient to have reached their maximal capacity, "No patient had been cured. Therapy provided systematically included CBT and GET. After treatment duration of 41 to 62 hours of rehabilitation per patient of which 83% group based, spread over 6 to 12 months, patients’ subjective feelings of fatigue were improved, but results concerning quality of life were equivocal. Psychological problems or psychiatric co-morbidities improved, but still fell outside the range of healthy adults. Physical capacity did not change; employment status decreased at the end of the therapy." The report noted that "It is difficult however, to judge these results, since no control group had been included."
A 2008 Cochrane systematic review included 4 studies which used group CBT and concluded that it was less effective than individual CBT at reducing fatigue at post-treatment. A 2007 meta-analysis stated that the one included study which tested group CBT had produced a similar effect to the other studies using individual CBT. In a more recent study of a multidisciplinary intervention which combined group CBT and GET with pharmacological treatment, at 12 months after completion this intervention was "slightly inferior" to usual care alone, resulting in no improvements to fatigue or health related quality of life, and worse physical function and bodily pain scores.
Alternatives to CBT
Some CFS patients have comorbid depression and/or anxiety. Children have been successfully treated using antidepressants and therapy. A 2009 survey of two Norwegian patient organizations (ME-association and MENiN) had found that out of 828 participants with CFS, 57% of those who had received help to "identify and challenge negative thought patterns" regarded this as useful.
Graded exercise therapy
Two systematic reviews cautiously conclude that some patients may benefit from graded exercise therapy (GET), although there are some limitations with the evidence and the generalizability of the findings. A 2012 systematic review concluded that despite the consistent positive outcomes of exercise therapy studies for CFS, "exercise therapy is not a cure for CFS", and "full recovery from CFS is rare".
A 2004 Cochrane systematic review included 5 eligible studies on GET and found statistically significant improvements to self-reported fatigue severity and physical functioning. This benefit was sustained after 6 months but became non-significant compared to the control group who did not receive GET. Functional work capacity was not significantly improved. GET had a tendency towards higher dropout rates, and although there was no evidence that exercise therapy worsened outcomes on average, no data was reported for adverse effects. The authors state that the evidence base and the precision of the results are limited, and encourage higher quality studies "that involve different patient groups and settings, and that measure additional outcomes such as adverse effects, quality of life and cost effectiveness over longer periods of time".
A 2006 systematic review published in the Journal of the Royal Society of Medicine included 5 eligible studies on GET and found an overall effect in the reduction of symptoms and improvement to physical functioning. GET had not been proven to restore the ability to work. Withdrawals were noted in some GET studies but difficult to interpret due to the poor reporting of adverse effects. The protocols for many clinical studies may have biased the sample towards those with less severe symptoms, and severely affected patients were not included in the studies of GET. The authors state the need for research to "define the characteristics of patients who would benefit from specific interventions and to develop clinically relevant objective outcome measures."
A New Zealand study suggests that GET may result in self-reported improvement in part by "reducing the degree to which patients focus on their symptoms." To avoid detrimental effects from GET, care must be taken to avoid the exacerbation of symptoms while catering the program to individual capabilities and the fluctuating nature of symptoms.
Patient organisations' surveys commonly report adverse effects with a survey of two Norwegian patient organizations (ME-association and MENiN) reporting that 79% of those with experience with graded training regarded this to worsen their health status.
Pragmatic rehabilitation is "a programme of gradually increasing activity designed collaboratively by the patient and the therapist". In response to an earlier successful trial, a larger trial was conducted, known as Fatigue Intervention by Nurses Evaluation. In the FINE trial, patients fulfilling Oxford 1991 CFS criteria who were allocated to pragmatic rehabilitation reported a statistically significant but "clinically modest" improvement in fatigue when compared to patients allocated to either "supportive listening" or "treatment as usual", but after 12 months follow-up there were no statistically significant differences. There was no significant improvement to physical functioning at any time. About 10% of the trial participants were non-ambulatory and about 30% met London ME criteria, but separate results for these groups were not published. In an accompanying editorial, possible reasons are given for why the earlier success was not replicated in this trial, and further research is encouraged; the patients in this trial had higher comorbidity and disability than patients in the earlier trial or most other trials, and received less sessions than most successful trials of CBT and GET. The question was also raised whether generalists are as successful as specialists in offering behavioural interventions.
Pacing techniques encourage behavioral change, but unlike cognitive behavioural therapy, acknowledge the typical patient fluctuations in symptom severity and delayed exercise recovery. Patients are advised to set manageable daily activity/exercise goals and balance their activity and rest to avoid possible over-doing which may worsen their symptoms. People who can function within their individual limits may then try to gradually increase activity and exercise levels (GET) while maintaining pacing methods. The goal is to increase over time the level of routine functioning of the individual. A small randomised controlled trial concluded pacing with GET had statistically better results than relaxation/flexibility therapy. A 2008 patient survey by Action for ME found pacing to be the most helpful treatment and a 2009 survey of two Norwegian patient organizations (ME-association and MENiN) had found that 96% evaluated pacing as useful.
The PACE trial was a large-scale five-year trial funded by the UK government which compared the efficacy and safety of four treatments: specialist medical care (SMC), SMC with CBT, SMC with GET, and SMC with adaptive pacing therapy (APT). The results were published in February 2011 and showed that CBT and GET were, when combined with SMC, each "moderately" effective compared to SMC alone. APT was not found to be effective when added to SMC.
Out of 3158 potential participants screened for eligibility, about 80% of candidates were excluded and 641 patients meeting the Oxford criteria for CFS were recruited. 160 were assigned to the APT group, 161 to the CBT group, 160 to the GET group and 160 to the SMC group. SMC alone reduced mean fatigue scores by 4.5, SMC with CBT reduced scores by 7.4 and SMC with GET reduced scores by 7.6. The addition of APT made no statistical difference. Physical functioning scores were also improved by CBT and GET compared to APT or SMC alone.
All patients met Oxford criteria, and when further stratified into groups of patients that also met the international CDC criteria and/or the London criteria for ME, a subgroup analysis found no significant differences in outcomes between the groups - in all cases CBT and GET resulted in statistically significant moderate improvements compared to SMC alone or APT.
Average 6 minute walking distance scores improved in the SMC alone group from 314 to 334 meters. The SMC plus CBT group showed no additional improvement over SMC alone. The SMC plus GET group walked an additional 35 meters. This increase was small compared to the distance walked by healthy elderly people, which was shown in one study to be 631 meters.
CBT was done on the basis of the fear avoidance theory of chronic fatigue syndrome. This theory regards CFS as being reversible and that cognitive responses (fear of engaging in activity) and behavioural responses (avoidance of activity) are linked and interact with physiological processes to perpetuate fatigue. The aim of treatment was to change the behavioural and cognitive factors assumed to be responsible for perpetuation of the participant’s symptoms and disability.
Graded exercise therapy (GET) was done on the basis of deconditioning and exercise intolerance theories of chronic fatigue syndrome. These theories assume that CFS is perpetuated by reversible physiological changes of deconditioning and avoidance of activity; these changes result in the deconditioning being maintained and an increased perception of effort during exertion and increased symptoms after unaccustomed activity, leading to further inactivity. The aim of treatment was to help the participant gradually return to appropriate physical activities, reverse the deconditioning, and thereby reduce fatigue and disability.
The trial reported that CBT and GET were "safe". A serious adverse event was defined as either: death, life-threatening, hospitalisation, increased severe disability for at least 4 weeks duration, any episode of deliberate self-harm. Serious adverse reactions to the therapies were recorded in two (1%) of the 159 patients in the APT group, three (2%) of the 161 patients in the CBT group, 2 (1%) of the 160 patients in the GET group and two (1%) of the 160 patients in the SMC group.
An analysis was done to determine the proportion of patients who recovered after each type of treatment during the PACE trial. Two measures of "recovery" were used: "trial recovery", meaning that the patient was in the normal range for fatigue and physical function, didn't meet the Oxford definition for CFS, and had a self-rated overall health score of "much better" or "very much better". The second measure of recovery, "clinical recovery", required that the patient not meet the CDC criteria for CFS or the London criteria for ME (in addition to the criteria for "trial recovery"). The figures for meeting "trial recovery" were: 22% after CBT, 22% after GET, 8% after APT and 7% after SMC. For "clinical recovery" the figures were very similar. The study only looked at recovery from the "current episode of the illness", and the CDC criteria were modified to only look at symptoms in the past week rather than the previous six months. According to the authors, "Our finding that 22–56% of participants met various composite or single criteria for recovery or improvement a year after starting either CBT or GET is therefore consistent with previously published studies. The NNT of 7 for recovery after both CBT and GET is within the range of the effects found for drug treatments in both general medical and psychiatric conditions"
Another paper examined cost-effectiveness and changes in service usage. Both CBT and GET passed common criteria for cost-effectiveness, and also had a higher probability of being the most cost-effective when compared to the APT and SMC groups. APT was not found to be cost-effective. However, there were no statistically significant differences between groups in measures for employment/production losses and total service/societal usage or costs. Moreover, welfare benefits or other financial payments increased for all groups during the trial, with no significant differences between groups. These latter costs were excluded from the cost-analyses, but the authors still reported them "given that they are important financial outlays".
Limitations of the trial included: patients younger than 18 years of age and those not able to attend hospital were excluded; and as with any therapy trial, participants, therapists, doctors, and research assessors were not masked to treatment allocation, resulting in an unblinded trial. The authors note that the primary outcomes were subjective and rated by participants, which could be subject to biases.
The publication of the trial results generated a vigorous response. Letters to the editor by some specialists and patient advocates expressed concern over generalisability of the results and questioned protocol changes during the course of the trial that resulted in some participants meeting criteria for “trial recovery” at baseline. The authors of the paper responded in a letter which stated that the protocol changes and other decisions were approved by the Trial Steering Committee. Patient groups expressed disappointment over news media interpreting the definition of “recovery to normal by trial criteria" as “cured”. Professor Malcolm Hooper submitted a 442 page response to the Medical Research Council and a shorter 43-page complaint to the Lancet. The MRC and the Lancet considered the submissions but rejected them. A Lancet editorial expressed suspicions of an active campaign to discredit the research."
In subsets of patients, various viruses have been reported as the causative agents of CFS, see Pathophysiology of chronic fatigue syndrome although so far consistent and compelling supportive evidence is still lacking. Others consider that treatment studies of subtypes may reduce the inconsistencies  A number of antiviral treatment studies have been conducted with inconsistent results.
Nucleic acid (double-stranded RNA) compounds represent a potential new class of pharmaceutical products that are designed to act at the molecular level, it is an inducer of interferon and is considered to be antiviral and immunomodulatory.
One RCT evaluated Ampligen and found an overall beneficial effect. In December 2009 the U.S. Food and Drug Administration (FDA) refused to approve a New Drug Application (NDA) to market and sell Ampligen for treatment of CFS. The FDA concluded that the two RCTs submitted "did not provide credible evidence of efficacy."
Hemispherx Biopharma performed additional analyses on their data and submitted a new NDA to the FDA in 2012. After reviewing the data, the FDA rejected the new application due to "insufficient safety and efficacy data".
A small 1988 RCT compared acyclovir against placebo and found that an equal proportion of patients improved from placebo and with active treatment. The authors concluded that the improvement reflected either spontaneous remission or the placebo effect. Three people withdrew from acyclovir treatment due to reversible renal failure.
A systematic review found two small RCTs that evaluated interferon. One RCT found an overall beneficial effect and the other showed some positive effects in relation to immunological outcomes only. The quality of both of these studies was considered poor. A 2007 review of research needs for CFS concluded that trials for interferon beta are an important priority.
A systematic review found five RCTs to have assessed the effects of immunoglobulin treatment for CFS; of these, two RCTs showed an overall beneficial effect and two RCTs showed some positive results, although in one of the studies this was for physiological effects only. The largest of the RCTs found no effect for the treatment. Another review concluded that "Given the weak evidence of benefit for immunotherapy, the potential harms indicate that it should not be offered as a treatment for CFS."
There is a striking paucity of RCTs evaluating pharmacological treatments in CFS. No pharmacological treatments have been established as a cure for CFS, but various drugs are used to manage the symptoms of CFS.
Antidepressants are often prescribed to CFS patients. Their purpose can be to treat secondary depression or mood swings, but low dosage tricyclic antidepressants are sometimes prescribed to improve sleep quality and reduce pain.
The evidence for antidepressants is mixed and their use remains controversial. In a review of pharmacological treatments for CFS, 5 trials of antidepressants were included but only one of these reported a statistically significant improvement in symptoms and this effect was only observed in patients who received 12 weeks of CBT before starting treatment with mirtazapine.
There have been 7 RCT’s, four trialling hydrocortisone, 2 with fludrocortisone and one with hydrocortisone plus fludrocortisone . Two RCT’s have found overall benefit for hydrocortisone, but it has not been recommended for clinical use.
A 2006 systematic review found one low-quality RCT of hydrocortisone which found a significant difference between groups for fatigue, but two other RCTs found no benefit for steroid treatment.
A randomized, placebo-controlled, double-blind therapeutic trial, conducted between 1992 and 1996 in a tertiary care research institution. 70 patients met the CDC criteria many comorbid with psychiatric diagnosis but who withheld concomitant treatment with other medications. Although hydrocortisone treatment (at a higher dose of 20–30 mg) was associated with some statistical improvement in symptoms of CFS, the authors concluded a degree of adrenal suppression precludes its practical use for CFS.
A double-blind, placebo-controlled crossover study in 26 patients with CFS of reduced nicotinamide adenine dinucleotide NADH reported positive results in 1999. No severe adverse effects were observed related to the study drug. One systemic review concluded that The RCT had several problems with its methods and a review concluded that there is no good evidence that NADH is of benefit for CFS patients.
An October 2011 study from Norway suggests that the cancer chemotherapy rituximab can help patients with chronic fatigue syndrome. A clinical trial has been completed and a new open-label trial has begun.
Staphylococcal toxoid vaccine
There have been 2 RCT’s with staphylococcal toxoid vaccine. A small RCT showed considerable benefit and a large follow up RCT showed overall benefit. However the quality of the follow-up RCT was low and there were relatively high levels of adverse effects. A review concluded that there is insufficient evidence for treatments of this type.
Fecal microbiota transplant
Gut dysfunction commonly co-occurs with CFS and abnormalities in the make up of the gut flora are also commonly found compared to healthy individuals such as unusually low levels of e-coli and unusually large numbers of enterococcus and streptococcus. An uncontrolled study of 60 CFS affected individuals who were given fecal microbiota transplant and followed up 15–20 years later 50 percent had significant improvement of symptoms. Another study involving treating chronic fatigue syndrome affected individuals with fecal microbiota transplant therapy and following the trial subjects over a period of 11–28 months found that 41 percent achieved persistent relief of symptoms.
Alternative medicine usage
People with CFS may use more alternative medicine treatments than people without CFS. In a twin study, 91% of twins with CFS and 71% without CFS used at least one alternative treatment. A large proportion of the study participants said alternative treatments were helpful.
A 2006 updated systematic review concluded that the supplements essential fatty acids and magnesium, have shown beneficial effects but only in one or two trials and further rigorous trials of these interventions would be helpful. A 2008 review found insufficient evidence to recommend dietary supplements as a treatment in chronic fatigue syndrome. One RCT compared a polynutrient supplement (containing several vitamins, minerals, and coenzymes, taken twice daily) with a placebo for 10 weeks, but found no difference in fatigue scores.
L-Carnitine is an amino acid which includes ALC, a group of natural compounds that have an important role in cellular function. It is required for the transport of fatty acids into the mitochondria during the breakdown of lipids(or fats) for the generation of metabolic energy including in muscles and in the brain. Two RCTs found benefit from dietary supplementation with L-carnitine or its esters. A 2006 systematic review reported one RCT with overall benefit, although there was no placebo control.
In 2008 a randomised double blind placebo controlled 6 months trial on 96 aged subjects with CFS symptoms administering Acetyl L Carnitine was reported. By the end of the treatment, significant differences between the two groups were found for both physical and mental fatigue and improvements in both the cognitive status and physical functions.
Essential fatty acids
A randomized controlled trial on patients diagnosed with post viral fatigue syndrome (PVFS) and deficient RBC levels, using essential fatty acids consisting of evening primrose oil containing n-6 GLA together with fishoil concentrate containing n-3 EPA and DHA showed significant overall improvement in symptoms and RBC essential fatty acid levels. However a subsequent RCT trying to replicate this study found no significant differences between the treatment and placebo group after treatment, and no significant differences in pre-treatment red-cell membrane lipids between the two groups. The different results may be explained by the patient selection: the first trial tested people with PVFS, whereas the second used the Oxford criteria for CFS. Also, the first trial used paraffin while the second trial used sunflower oil which is better tolerated and less likely to adversely affect the placebo group. 
Positive results from a trial of magnesium delivered by injection to magnesium-deficient CFS patients were published in 1991, but three subsequent studies did not find magnesium deficiency as a general problem in CFS patients. A 2008 review concluded that there is no good evidence that intramuscular magnesium is of benefit in CFS.
Both oral and injected Vitamin B12 have been suggested as treatments for generalized fatigue since the 1950s, however recent studies do not suggest any benefit from it, either for generalized fatigue or CFS specifically. Further research is needed, however, as studies to date have been small and used inconsistent dosing regimens.
It was previously assumed that placebo response rates in patients with chronic fatigue syndrome (CFS) are unusually high, "at least 30% to 50%", because of the subjective reporting of symptoms and the fluctuating nature of the condition. However, a meta-analysis found that the pooled response rate in the placebo group was 19.6%, lower than the usually reported one third response in other medical conditions. The authors offer possible explanations for this result: CFS is widely understood to be difficult to treat, which could reduce expectations of improvement. In context of evidence showing placebos do not have powerful clinical effects when compared to no treatment, a low rate of spontaneous remission in CFS could contribute to reduced improvement rates in the placebo group. Intervention type also contributed to the heterogeneity of the response, low patient and provider expectations regarding psychological treatment may explain particularly low placebo responses to psychiatric treatments.
A 2014 systematic review reported that estimates of recovery from CFS ranged between 0 and 66% in intervention studies and from 2.6 to 62% in naturalistic studies. There was a lack of consensus in the literature on how recovery should be defined, with almost all of the 22 included studies measuring recovery differently. Recovery was operationally defined by reference to, either alone or in combination: fatigue or related symptoms; function; premorbid function; and/or brief global assessment (which was the most common outcome measure, but does not provide information on symptoms and function, and does not "provide assurance that patients have substantially recovered rather than simply improved"). Focusing on only fatigue or function may overestimate recovery rates, because patients may show selective rather than overall change. A patient with reduced self-reported fatigue may still experience functional disruptions, pain, sleep disturbances, or malaise. "Recovery" in the reviewed studies was often based on limited assessments, less than a full restoration of health, and self-reports with a general lack of more objective measures. In the absence of definitive measures, recovery criteria should set high but reasonable standards for behavioural recovery which approach restoration of pre-morbid health. When objective measures are used, such as the relatively objective behavioural measure of actigraphy, the results have been contrary to the cognitive behavioural model of CFS which predicts increased physical functioning as a result of intervention, as otherwise 'successful' trials did not find significant changes in physical activity. The authors state "a more modest interpretation of 'recovery' might characterize such outcomes as successful adaptation of illness-related behaviour and attitudes to ongoing but perhaps diminished illness", "improved or recovered patients may have continued to avoid activity levels that provoked debilitating postexertional symptom flare-ups", which "would seem to be more consistent with a hypothesis of successful adaptation rather than recovery". It was concluded that more precise and accurate labels other than "recovery" (e.g. clinically significant improvement) may be more appropriate and informative for the improvements reported in previous research, and in keeping with commonly understood conceptions of recovery from illness, recommended a consistent definition of recovery that "captures a broad-based return to health with assessments of both fatigue and function as well as the patient’s perceptions of his/her recovery status" and "the recovery time following physical and mental exertion".
A 2012 systematic review on exercise therapy for CFS reported that exercise therapy is not a cure for CFS. The authors stated that "Despite the consistent positive outcomes of exercise therapy studies for CFS, full recovery from CFS is rare. In addition, exercise therapy is not a sole treatment for people with CFS. A comprehensive treatment for CFS comprises of education of the aetiology and pathophysiology of the illness, stress management, cognitive restructuring, sleep hygiene and GET together with graded activity. But even such a comprehensive rehabilitation programme only rarely results in full recovery."
- Rimes K.A.; Chalder T. (2005). "Treatments for chronic fatigue syndrome.". Occ. Med. (London) 55 (1): 32–9. doi:10.1093/occmed/kqi015. PMID 15699088.
- Luyten, P; Van Houdenhove, B; Pae, CU et al. (December 2008). "Treatment of chronic fatigue syndrome: findings, principles and strategies.". Psychiatry Investig. 5 (4): 209–12. doi:10.4306/pi.2008.5.4.209. PMC 2796012. PMID 20046339.
- Pheby, Derek; Saffron, Lisa (October–December 2009). "Risk factors for severe ME/CFS" (PDF). Biol. Med. 1 (4): 50–74. ISSN 0974-8369.
- Chambers, Duncan; Bagnall, Anne-Marie; Hempel, Susanne; Forbes, Carol (2006). "Interventions for the treatment, management and rehabilitation of patients with chronic fatigue syndrome/myalgic encephalomyelitis: an updated systematic review". J. R. Soc. Med. 99 (10): 506–20. doi:10.1258/jrsm.99.10.506. PMC 1592057. PMID 17021301.
- Van Cauwenbergh D1, De Kooning M, Ickmans K, Nijs J. (2012). "How to exercise people with chronic fatigue syndrome: evidence-based practice guidelines.". Eur J Clin Invest 42 (10): 1136–4. doi:10.1111/j.1365-2362.2012.02701.x. PMID 22725992.
- Price, Jonathan R; Mitchell, Edward; Tidy, Elizabeth; Hunot, Vivien (2008). "Cognitive behaviour therapy for chronic fatigue syndrome in adults". Cochrane Library (3): CD001027. doi:10.1002/14651858.CD001027.pub2. PMID 18646067.
- Sharpe, Michael; Hawton, Keith; Simkin, Sue et al. (January 1996). "Cognitive behaviour therapy for the chronic fatigue syndrome: a randomised controlled trial". BMJ 312 (7022): 22–6. doi:10.1136/bmj.312.7022.22. PMC 2349693. PMID 8555852.
- Reid, Steven; Chalder, Trudie; Cleare, Anthony et al. (26 May 2011). "Chronic fatigue syndrome". Clinical Evidence. BMJ Publishing Group.
- Deale A, Husain K, Chalder T, Wessely S (December 2001). "Long-term outcome of cognitive behavior therapy versus relaxation therapy for chronic fatigue syndrome: a 5-year follow-up study". Am J Psychiatry 158 (12): 2038–42. doi:10.1176/appi.ajp.158.12.2038. PMID 11729022.
- Malouff JM et al. (June 2008). "Efficacy of cognitive behavioral therapy for chronic fatigue syndrome: a meta-analysis". Clin Psychol Rev 28 (5): 736–45. doi:10.1016/j.cpr.2007.10.004. PMID 18060672.
- Wiborg JF, Knoop H, Stulemeijer M, Prins JB, Bleijenberg G (January 2010). "How does cognitive behaviour therapy reduce fatigue in patients with chronic fatigue syndrome? The role of physical activity". Psychol Med 40 (8): 1–7. doi:10.1017/S0033291709992212. PMID 20047707.
- Adamowicz JL, Caikauskaite I, Friedberg F (2014). "Defining recovery in chronic fatigue syndrome: a critical review". Qual Life Res. 23 (9): 2407–16. doi:10.1007/s11136-014-0705-9. PMID 24791749.
- Castell, Bronwyn D.; Kazantzis, Nikolaos; Moss-Morris, Rona E. (1 December 2011). "Cognitive Behavioral Therapy and Graded Exercise for Chronic Fatigue Syndrome: A Meta-Analysis". Clinical Psychology: Science and Practice 18 (4): 311–324. doi:10.1111/j.1468-2850.2011.01262.x.
- Clark C, Buchwald D, MacIntyre A, Sharpe M, Wessely S (2002). "Chronic fatigue syndrome: a step towards agreement" (PDF). Lancet 359 (9301): 97–8. doi:10.1016/S0140-6736(02)07336-1. PMID 11809249.
- White PD, Sharpe MC, Chalder T, DeCesare JC, Walwyn R (2007). "Protocol for the PACE trial: A randomised controlled trial of adaptive pacing, cognitive behaviour therapy, and graded exercise as supplements to standardised specialist medical care versus standardised specialist medical care alone for patients with the chronic fatigue syndrome/myalgic encephalomyelitis or encephalopathy". BMC Neurol 7: 6. doi:10.1186/1471-2377-7-6. PMC 2147058. PMID 17397525.
- Twisk FN, Maes M (August 2009). "A review on cognitive behavorial therapy (CBT) and graded exercise therapy (GET) in myalgic encephalomyelitis (ME) / chronic fatigue syndrome (CFS): CBT/GET is not only ineffective and not evidence-based, but also potentially harmful for many patients with ME/CFS". Neuro Endocrinol Lett 30 (3): 284–299. PMID 19855350.
- Working Party on CFS/ME (January 2002). "Report of the Working Party on CFS/ME to the Chief Medical Officer for England and Wales". Department of Health. alternative URL: 
- "Survey Summary Report 2008" (PDF). Action for ME. 2008. p. 13. Retrieved 8 March 2010.
- Sabine, Stordeur; Nancy, Thiry; Marijke, Eyssen (2008). Chronisch Vermoeidheidssyndroom: diagnose, behandeling en zorgorganisatie [Fatigue Syndrome: diagnosis, treatment and organisation of care] (PDF) (Technical report) (in Dutch). KCE (Belgian Healthcare Knowledge Center). 88A.
- Núñez, Montserrat; Fernández-Solà, Joaquim; Nuñez, Esther; Fernández-Huerta, José-Manuel; Godás-Sieso, Teresa; Gomez-Gil, Esther (March 2011). "Health-related quality of life in patients with chronic fatigue syndrome: group cognitive behavioural therapy and graded exercise versus usual treatment. A randomised controlled trial with 1 year of follow-up". Clin. Rheumatol. 30 (3): 381–9. doi:10.1007/s10067-010-1677-y. PMID 21234629.
- Ridsdale L; Godfrey E; Chalder T et al. (January 2001). "Chronic fatigue in general practice: is counselling as good as cognitive behaviour therapy? A UK randomised trial". Br J Gen Pract 51 (462): 19–24. PMC 1313894. PMID 11271868.
- Youssefi M, Linkowski P (September 2002). "[Chronic fatigue syndrome: psychiatric perspectives]". Revue Médicale de Bruxelles (in French) 23 (4): A299–304. PMID 12422451.
- Patel MX, Smith DG, Chalder T, Wessely S (October 2003). "Chronic fatigue syndrome in children: a cross sectional survey". Arch. Dis. Child. 88 (10): 894–8. doi:10.1136/adc.88.10.894. PMC 1719321. PMID 14500310.
- Bjørkum T, Wang CE, Waterloo K (June 2009). "[Patients' experience with treatment of chronic fatigue syndrome]". Tidsskr nor Laegeforen 129 (12): 1214–6. doi:10.4045/tidsskr.09.35791. PMID 19521443.
- Edmonds M, McGuire H, Price J (2004). Price, Jonathan R, ed. "Exercise therapy for chronic fatigue syndrome". Cochrane Database Syst Rev (3): CD003200. doi:10.1002/14651858.CD003200.pub2. PMID 15266475.
- Moss-Morris R, Sharon C, Tobin R, Baldi JC (March 2005). "A randomized controlled graded exercise trial for chronic fatigue syndrome: outcomes and mechanisms of change". J Health Psychol 10 (2): 245–59. doi:10.1177/1359105305049774. PMID 15723894.
- Nijs J, Paul L, Wallman K (April 2008). "Chronic fatigue syndrome: an approach combining self-management with graded exercise to avoid exacerbations". J Rehabil Med 40 (4): 241–7. doi:10.2340/16501977-0185. PMID 18382818.
- Wearden AJ, Dowrick C, Chew-Graham C, Bentall RP, Morriss RK, Peters S, Riste L, Richardson G, Lovell K, Dunn G; Fatigue Intervention by Nurses Evaluation (FINE) trial writing group and the FINE trial group. Collaborators (23): Bennett C, Bentall R, Booth L, Brocki J, Cahill G, Chapman A, Chew-Graham C, Connell S, Dowrick C, Dunn G, Fleetwood D, Ibbotson L, Jerman D, Lovell K, Mann J, Morriss R, Peters S, Powell P, Quarmby D, Richardson G, Riste L, Wearden A, Williams J. (April 2010). "Nurse led, home based self help treatment for patients in primary care with chronic fatigue syndrome: randomised controlled trial". BMJ 340: c1777. doi:10.1136/bmj.c1777. PMC 2859122. PMID 20418251.
- Moss-Morris R, Hamilton W (April 2010). "Pragmatic rehabilitation for chronic fatigue syndrome". BMJ 340: c1799. doi:10.1136/bmj.c1799. PMID 20418252.
- Nijs J, Meeus M, De Meirleir K (August 2006). "Chronic musculoskeletal pain in chronic fatigue syndrome: recent developments and therapeutic implications". Man Ther 11 (3): 187–91. doi:10.1016/j.math.2006.03.008. PMID 16781183.
- Wallman KE, Morton AR, Goodman C, Grove R, Guilfoyle AM (May 2004). "Randomised controlled trial of graded exercise in chronic fatigue syndrome". Med. J. Aust. 180 (9): 444–8. PMID 15115421.
- "PACE Trial - FAQ". Retrieved 9 May 2014.
- White, P.; Goldsmith, K.; Johnson, A. et al. (2011). "Comparison of adaptive pacing therapy, cognitive behaviour therapy, graded exercise therapy, and specialist medical care for chronic fatigue syndrome (PACE): a randomised trial". The Lancet 377 (9768): 823–836. doi:10.1016/S0140-6736(11)60096-2.
- Kewley, Andrew James (May 2011). "The PACE trial in chronic fatigue syndrome". The Lancet 377 (9780): 1832; author reply 1834–5. doi:10.1016/S0140-6736(11)60681-8. PMID 21592552.
- White, P. D.; Goldsmith, K.; Johnson, A. L.; Chalder, T.; Sharpe, M. (31 January 2013). "Recovery from chronic fatigue syndrome after treatments given in the PACE trial". Psychol. Med.: 1–9. doi:10.1017/S0033291713000020.
- McCrone, Paul; Sharpe, Michael; Chalder, Trudie; Knapp, Martin; Johnson, Anthony L.; Goldsmith, Kimberley A.; White, Peter D. (August 2012). "Adaptive pacing, cognitive behaviour therapy, graded exercise, and specialist medical care for chronic fatigue syndrome: a cost-effectiveness analysis". PLOS ONE 7 (8): e40808. doi:10.1371/journal.pone.0040808. PMC 3411573. PMID 22870204.
- Mitchell, John T (May 2011). "The PACE trial in chronic fatigue syndrome". The Lancet 377 (9780): 1831; author reply 1834–5. doi:10.1016/S0140-6736(11)60683-1. PMID 21592555.
- Feehan, Sarah M (May 2011). "The PACE trial in chronic fatigue syndrome". The Lancet 377 (9780): 1831–2; author reply 1834–5. doi:10.1016/S0140-6736(11)60688-0. PMID 21592556.
- Stouten, Bart; Goudsmit, Ellen M; Riley, Neil (May 2011). "The PACE trial in chronic fatigue syndrome". The Lancet 377 (9780): 1832–3; author reply 1834–5. doi:10.1016/S0140-6736(11)60685-5. PMID 21592558.
- Kindlon, Tom (May 2011). "The PACE trial in chronic fatigue syndrome". The Lancet 377 (9780): 1833; author reply 1834–5. doi:10.1016/S0140-6736(11)60684-3. PMID 21592560.
- Shinohara, Mieko (May 2011). "The PACE trial in chronic fatigue syndrome". The Lancet 377 (9780): 1833–4; author reply 1834–5. doi:10.1016/S0140-6736(11)60686-7. PMID 21592561.
- White, P, Goldsmith, K, Johnson, A et al. (May 2011). "The PACE trial in chronic fatigue syndrome - Author's reply". The Lancet 377 (9780): 1834–5. doi:10.1016/S0140-6736(11)60651-X.
- Shepherd C (August 2013). "Recovery from chronic fatigue syndrome after treatments given in the PACE trial". Psychol. Med. 43 (8): 1790–1. doi:10.1017/S003329171300130X. PMID 23866116.
- "Patients' power and PACE". Editorial. The Lancet 377 (9780): 1808. May 2011. doi:10.1016/S0140-6736(11)60696-X. PMID 21592553.
- Hawkes, Nigel (June 2011). "Dangers of research into chronic fatigue syndrome". Comment. BMJ 342: d3780. doi:10.1136/bmj.d3780. PMID 21697226.
- Sanders P, Korf J (2008). "Neuroaetiology of chronic fatigue syndrome: an overview". World J. Biol. Psychiatry 9 (3): 165–71. doi:10.1080/15622970701310971. PMID 17853290.
- Jason LA, Corradi K, Torres-Harding S, Taylor RR, King C (March 2005). "Chronic fatigue syndrome: the need for subtypes". Neuropsychol Rev 15 (1): 29–58. doi:10.1007/s11065-005-3588-2. PMID 15929497.
- Whiting P, Bagnall AM, Sowden AJ, Cornell JE, Mulrow CD, Ramírez G (September 2001). "Interventions for the treatment and management of chronic fatigue syndrome: a systematic review". JAMA 286 (11): 1360–8. doi:10.1001/jama.286.11.1360. PMID 11560542.
- George, John (Modified: Thursday, December 3, 2009). "FDA rejects Hemispherx's chronic fatigue drug Ampligen". Philadelphia Business Journal. Retrieved 2010-02-12. Check date values in:
- De Clercq E, Neyts J (2009). "Antiviral agents acting as DNA or RNA chain terminators". Handb Exp Pharmacol. Handbook of Experimental Pharmacology 189 (189): 53–84. doi:10.1007/978-3-540-79086-0_3. ISBN 978-3-540-79085-3. PMID 19048197.
- Straus SE; Dale JK; Tobi M et al. (December 1988). "Acyclovir treatment of the chronic fatigue syndrome. Lack of efficacy in a placebo-controlled trial". N. Engl. J. Med. 319 (26): 1692–8. doi:10.1056/NEJM198812293192602. PMID 2849717.
- Kerr JR; Christian P; Hodgetts A et al. (February 2007). "Current research priorities in chronic fatigue syndrome/myalgic encephalomyelitis: disease mechanisms, a diagnostic test and specific treatments". J. Clin. Pathol. 60 (2): 113–6. doi:10.1136/jcp.2006.042374. PMC 1860619. PMID 16935968.
- Kreijkamp-Kaspers S, Brenu EW, Marshall S, Staines D, Van Driel ML. (November 2011). "Treating chronic fatigue syndrome - a study into the scientific evidence for pharmacological treatments" (PDF). Aust Fam Physician 40 (11): 907–12. PMID 22059223.
- Bell, David S. (1994). The Doctor's Guide to Chronic Fatigue Syndrome. Da Capo Press. p. 163. ISBN 0-201-40797-3.
- Jackson JL, O'Malley PG, Kroenke K (March 200). "Antidepressants and cognitive-behavioral therapy for symptom syndromes". CNS Spectr 11 (3): 212–22. PMID 16575378. Check date values in:
- Pae CU, Marks DM, Patkar AA, Masand PS, Luyten P, Serretti A (July 2009). "Pharmacological treatment of chronic fatigue syndrome: focusing on the role of antidepressants". Expert Opin Pharmacother 10 (10): 1561–70. doi:10.1517/14656560902988510. PMID 19514866.
- Chambers D, Bagnall AM, Hempel S, Forbes C (October 2006). "Interventions for the treatment, management and rehabilitation of patients with chronic fatigue syndrome/myalgic encephalomyelitis: an updated systematic review". J R Soc Med 99 (10): 506–20. doi:10.1258/jrsm.99.10.506. PMC 1592057. PMID 17021301.
- McKenzie R; O'Fallon A; Dale J et al. (1998). "Low-dose hydrocortisone for treatment of chronic fatigue syndrome: a randomized controlled trial". JAMA 280 (12): 1061–6. doi:10.1001/jama.280.12.1061. PMID 9757853.
- Forsyth LM, Preuss HG, MacDowell AL, Chiazze L, Birkmayer GD, Bellanti JA (February 1999). "Therapeutic effects of oral NADH on the symptoms of patients with chronic fatigue syndrome". Ann. Allergy Asthma Immunol. 82 (2): 185–91. doi:10.1016/S1081-1206(10)62595-1. PMID 10071523.
- Fluge O, Mella O (July 2009). "Clinical impact of B-cell depletion with the anti-CD20 antibody rituximab in chronic fatigue syndrome: a preliminary case series". BMC Neurology 9: 28. doi:10.1186/1471-2377-9-28. PMC 2711959. PMID 19566965.
- Drug Intervention in Chronic Fatigue Syndrome
- "Rituximab Trial Shows Promise". Retrieved 2011-11-04.
- Andersson, M; Bagby, JR; Dyrehag, L; Gottfries, C (1998). "Effects of staphylococcus toxoid vaccine on pain and fatigue in patients with fibromyalgia/chronic fatigue syndrome". European journal of pain (London, England) 2 (2): 133–142. doi:10.1016/S1090-3801(98)90006-4. PMID 10700309.
- Smits LP, Bouter KE, de Vos WM, Borody TJ, Nieuwdorp M (November 2013). "Therapeutic potential of fecal microbiota transplantation". Gastroenterology 145 (5): 946–53. doi:10.1053/j.gastro.2013.08.058. PMID 24018052.
- Aroniadis OC, Brandt LJ (January 2013). "Fecal microbiota transplantation: past, present and future". Curr. Opin. Gastroenterol. 29 (1): 79–84. doi:10.1097/MOG.0b013e32835a4b3e. PMID 23041678.
- Jones JF, Maloney EM, Boneva RS, Jones AB, Reeves WC (2007). "Complementary and alternative medical therapy utilization by people with chronic fatiguing illnesses in the United States". BMC Complement Altern Med 7: 12. doi:10.1186/1472-6882-7-12. PMC 1878505. PMID 17459162.
- Afari N; Eisenberg DM; Herrell R et al. (2000). "Use of alternative treatments by chronic fatigue syndrome discordant twins". Integr Med 2 (2): 97–103. doi:10.1016/S1096-2190(99)00017-7. PMID 10882883.
- Inazu M, Matsumiya T (June 2008). "[Physiological functions of carnitine and carnitine transporters in the central nervous system]". Nihon Shinkei Seishin Yakurigaku Zasshi (in Japanese) 28 (3): 113–20. PMID 18646596.
- Malaguarnera M; Gargante MP; Cristaldi E et al. (2008). "Acetyl L-carnitine (ALC) treatment in elderly patients with fatigue". Arch Gerontol Geriatr 46 (2): 181–90. doi:10.1016/j.archger.2007.03.012. PMID 17658628.
- Behan PO, Behan WM, Horrobin D (1990). "Effect of high doses of essential fatty acids on the postviral fatigue syndrome". Acta Neurol. Scand. 82 (3): 209–16. doi:10.1111/j.1600-0404.1990.tb04490.x. PMID 2270749.
- Warren G, McKendrick M, Peet M (1999). "The role of essential fatty acids in chronic fatigue syndrome. A case-controlled study of red-cell membrane essential fatty acids (EFA) and a placebo-controlled treatment study with high dose of EFA". Acta Neurol. Scand. 99 (2): 112–6. doi:10.1111/j.1600-0404.1999.tb00667.x. PMID 10071170.
- Cox IM, Campbell MJ, Dowson D (1991). "Red blood cell magnesium and chronic fatigue syndrome". Lancet 337 (8744): 757–60. doi:10.1016/0140-6736(91)91371-Z. PMID 1672392.
- "Does Vitamin B12 Help Relieve Fatigue?". Medscape. Retrieved 2010-12-10.
- Cho HJ, Hotopf M, Wessely S (2005). "The placebo response in the treatment of chronic fatigue syndrome: A systematic review and meta-analysis". Psychosom Med 67 (2): 301–13. doi:10.1097/01.psy.0000156969.76986.e0. PMID 15784798. Retrieved 2008-12-12.