Assessing fatigue in myalgic encephalomyelitis/chronic fatigue syndrome patients before and after treatment with bright light therapy: A prospective randomized controlled crossover study

Abstract:

Objective: The aim of the current study was to test the effectiveness of treatment with bright light therapy (BLT) on fatigue and cognitive function in patients with Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS). A randomized-controlled cross-over study design was chosen in order to provide all patients access to BLT treatment and account for placebo effects.

Methods: In this study, a total of 36 outpatients with a diagnosis of ME/CFS according to the criteria of the Institute of Medicine (2015) were randomly assigned to a cross-over design starting out either with BLT or waitlist for the course of 2 weeks with a washout phase in between. Portable light boxes emitting full-spectrum visible light with a luminance intensity of 10,000 lux were used by the participants at home. Primary outcome of the study was fatigue as assessed by Chalder Fatigue Score (CFQ) and the secondary outcome variable was cognitive function assessed per standardized test battery (Test of Attentional Performance – TAP).

Results: The primary outcome variable fatigue was not significantly improved after treatment with BLT compared to wait list in the full crossover design, although fatigue scores improved immediately after two weeks of BLT. Additionally, patients showed decreased reaction time after treatment with BLT in a subtest of TAP compared to wait list. Over 45 % of patients were diagnosed with postural tachycardia syndrome.

Conclusion: BLT for two weeks is not effective for the treatment of fatigue in ME/CFS, but it might have beneficial effects on attention in patients with ME/CFS. The clinical trial is registered with www.

Clinicaltrials: gov (NCT06635928).

Source: Ludwig B, Hauer L, Böck M, Schillerwein-Kral C, Weyer L, Moser D, Zehetmayer S, Trimmel K, Seidel S. Assessing fatigue in myalgic encephalomyelitis/chronic fatigue syndrome patients before and after treatment with bright light therapy: A prospective randomized controlled crossover study. Sleep Med. 2025 Mar 14;129:369-374. doi: 10.1016/j.sleep.2025.03.003. Epub ahead of print. PMID: 40120538. https://www.sciencedirect.com/science/article/pii/S1389945725001200 (Full text)

Chronic fatigue syndrome and seasonal affective disorder: comorbidity, diagnostic overlap, and implications for treatment

Abstract:

This study aimed to determine symptom patterns in patients with chronic fatigue syndrome (CFS), in summer and winter. Comparison data for patients with seasonal affective disorder (SAD) were used to evaluate seasonal variation in mood and behavior, atypical neurovegetative symptoms characteristic of SAD, and somatic symptoms characteristic of CFS.

Rating scale questionnaires were mailed to patients previously diagnosed with CFS. Instruments included the Personal Inventory for Depression and SAD (PIDS) and the Systematic Assessment for Treatment Emergent Effects (SAFTEE), which catalogs the current severity of a wide range of somatic, behavioral, and affective symptoms. Data sets from 110 CFS patients matched across seasons were entered into the analysis. Symptoms that conform with the Centers for Disease Control and Prevention (CDC) case definition of CFS were rated as moderate to very severe during the winter months by varying proportions of patients (from 43% for lymph node pain or enlargement, to 79% for muscle, joint, or bone pain).

Fatigue was reported by 92%. Prominent affective symptoms included irritability (55%), depressed mood (52%), and anxiety (51%). Retrospective monthly ratings of mood, social activity, energy, sleep duration, amount eaten, and weight change showed a coherent pattern of winter worsening.

Of patients with consistent summer and winter ratings (n = 73), 37% showed high global seasonality scores (GSS) > or = 10. About half this group reported symptoms indicative of major depressive disorder, which was strongly associated with high seasonality.

Hierarchical cluster analysis of wintertime symptoms revealed 2 distinct clinical profiles among CFS patients: (a) those with high seasonality, for whom depressed mood clustered with atypical neurovegetative symptoms of hypersomnia and hyperphagia, as is seen in SAD; and (b) those with low seasonality, who showed a primary clustering of classic CFS symptoms (fatigue, aches, cognitive disturbance), with depressed mood most closely associated with irritability, insomnia, and anxiety.

It appears that a subgroup of patients with CFS shows seasonal variation in symptoms resembling those of SAD, with winter exacerbation. Light therapy may provide patients with CFS an effective treatment alternative or adjunct to antidepressant drugs.

 

Source: Terman M, Levine SM, Terman JS, Doherty S. Chronic fatigue syndrome and seasonal affective disorder: comorbidity, diagnostic overlap, and implications for treatment. Am J Med. 1998 Sep 28;105(3A):115S-124S. http://www.ncbi.nlm.nih.gov/pubmed/9790493

 

Lack of seasonal variation of symptoms in patients with chronic fatigue syndrome

Abstract:

Several of the symptoms involved in chronic fatigue syndrome (CFS) such as fatigue, hypersomnia, hyperphagia, weight gain, and mood show seasonal variations in the general population. The aim of this study was to investigate whether patients with CFS experience seasonal fluctuations in these symptoms as well.

Seasonal variation of symptoms was assessed in a group of 41 patients with CFS and 41 controls closely matched for age, gender, and city of residence. Participants were recruited across the US and were asked to complete the Seasonal Pattern Assessment Questionnaire (SPAQ) and the Profile of Mood States (POMS). CFS patients showed significantly lower scores on multiple SPAQ-derived measures as compared with controls. These included seasonal variation in energy, mood, appetite, weight, and sleep length.

Patients also reported a significantly reduced sensitivity toward sunny, dry, and long days than controls. No association was noted between intensity of seasonal changes and severity of depressive symptoms. Patients with CFS exhibit an abnormally reduced seasonal variation in mood and behavior and would not be expected to benefit from light therapy.

 

Source: García-Borreguero D, Dale JK, Rosenthal NE, Chiara A, O’Fallon A, Bartko JJ, Straus SE. Lack of seasonal variation of symptoms in patients with chronic fatigue syndrome. Psychiatry Res. 1998 Feb 9;77(2):71-7. http://www.ncbi.nlm.nih.gov/pubmed/9541142