Evidence browser

E2 ModerateReviewPEM not requiredReview-Narrative

General practitioners' experience of the chronic fatigue syndrome.

Ho-Yen, D O, McNamara, I·The British journal of general practice : the journal of the Royal College of General Practitioners·1991

Researchers surveyed doctors in Scotland to understand how common ME/CFS is and how they view the condition. Most doctors (71%) believed ME/CFS is real, though some were uncertain. The study found about 1-2 people per 1,000 patients have ME/CFS, with more women affected than men, and it particularly affects people in their 30s and 40s.

Chronic fatigue syndrome in northern Nevada.

Daugherty, S A, Henry, B E, Peterson, D L et al.·Reviews of infectious diseases·1991

Between 1984 and 1988, doctors in northern Nevada identified over 400 patients with ME/CFS and found a common pattern of symptoms and lab abnormalities in those who were moderately to severely ill. The pattern included extreme fatigue, sore throats, memory and concentration problems, muscle pain, and specific changes in immune system markers and brain imaging. Some patients experienced more serious problems like seizures or cognitive decline.

E2 ModerateCohortPEM not requiredCase-Control

A comprehensive immunological analysis in chronic fatigue syndrome.

Gupta, S, Vayuvegula, B·Scandinavian journal of immunology·1991

Researchers compared immune system cells and antibodies in 20 ME/CFS patients and 20 healthy people to see if there were differences. They found that ME/CFS patients had fewer natural killer cells (immune cells that fight infections), some changes in how their immune cells communicate with each other, and weaker responses to certain types of immune challenges. These findings suggest the immune system works differently in ME/CFS.

E2 ModerateCohortPEM not requiredCase-Control

Antibodies to Epstein-Barr virus in patients with chronic fatigue.

Matthews, D A, Lane, T J, Manu, P·Southern medical journal·1991

This study tested whether Epstein-Barr virus (EBV) antibodies in the blood can help identify ME/CFS patients. Researchers compared 35 fatigued patients with signs of chronic EBV infection to 35 matched fatigued patients without these signs. They found very few differences between the groups, suggesting that EBV antibody testing is not particularly useful for diagnosing or understanding chronic fatigue.

E2 ModerateBehavioralPEM not requiredCross-Sectional

Biopsychosocial aspects of chronic fatigue syndrome (myalgic encephalomyelitis).

Yeomans, J D, Conway, S P·The Journal of infection·1991

This study looked at 15 people with chronic fatigue referred by their doctors. Researchers found that while most patients reported feeling emotionally distressed, only a few actually had a diagnosed depression disorder. Many patients struggled with work and daily activities. Tests for infections, blood abnormalities, and immune problems came back normal, suggesting ME/CFS is not simply caused by one medical problem.

E2 ModerateCohortPEM not requiredObservational

Chronic fatigue syndrome in Minnesota.

Peterson, P K, Schenck, C H, Sherman, R·Minnesota medicine·1991

This study looked at 135 people in Minnesota with ME/CFS to understand who gets the disease and how it develops. Most patients reported that their illness started suddenly with what looked like an infection, and fatigue was their worst symptom. When researchers checked in with some patients a year later, none had fully recovered, though about 40% felt somewhat better.

E2 ModerateCohortPEM not requiredCase-Control

Chronic fatigue syndrome: I. Epstein-Barr virus immune response and molecular epidemiology.

Jones, J F, Streib, J, Baker, S et al.·Journal of medical virology·1991

This study looked at how the immune system responds to Epstein-Barr virus (EBV) in ME/CFS patients compared to healthy people who have been infected with EBV. Researchers found that immune cells from ME/CFS patients were much more likely to grow uncontrollably in the lab (30% vs 8%), and patients showed more signs of active viral infection in their blood. These findings suggest that some ME/CFS patients may have difficulty controlling EBV reactivation.

E2 ModerateCohortPEM unclearCross-Sectional

Primary fibromyalgia and the chronic fatigue syndrome.

Wysenbeek, A J, Shapira, Y, Leibovici, L·Rheumatology international·1991

This study looked at 33 people with fibromyalgia to see how many also had ME/CFS. While most reported significant fatigue, only about one in five people met the full criteria for ME/CFS. The researchers found that symptoms like swollen lymph nodes and fever were rare in fibromyalgia patients but might be more common in ME/CFS, suggesting these could help doctors tell the two conditions apart.

Diagnostics

Search for an association between Epstein-Barr virus infection and the chronic fatigue syndrome.

Joncas, J H·Canada diseases weekly report = Rapport hebdomadaire des maladies au Canada·1991

This study looked at whether Epstein-Barr virus (EBV), a common virus that causes mononucleosis, might be connected to ME/CFS. Researchers compared people with ME/CFS to other groups to see if they had different levels of EBV infection or antibodies. This was one of the early investigations into potential viral causes of ME/CFS.

Virology laboratory diagnosis of chronic fatigue syndrome.

McLaughlin, B·Canada diseases weekly report = Rapport hebdomadaire des maladies au Canada·1991

This 1991 study examined how laboratory tests using virology (the study of viruses) could help diagnose ME/CFS. The research looked at whether finding certain viruses in patients' blood or other samples could confirm whether someone has ME/CFS. This was an important early step in trying to understand if viruses play a role in this illness.

E2 ModerateBehavioralPEM not requiredCross-Sectional

Depression and somatization in the chronic fatigue syndrome.

Lane, T J, Manu, P, Matthews, D A·The American journal of medicine·1991

This study looked at 60 patients diagnosed with chronic fatigue syndrome (CFS) to see how often they had depression or other psychiatric conditions. Researchers found that most CFS patients (78%) had some kind of mental health disorder, similar to a control group of fatigued people without CFS. However, CFS patients were more likely to have somatization disorder (believing physical symptoms have a physical cause) and were more likely to attribute their illness to a physical problem rather than psychological stress.

No association of HLA class II antigens in chronic fatigue syndrome.

Middleton, D, Savage, D A, Smith, D G·Disease markers·1991

This study examined whether certain immune system markers called HLA class II antigens were associated with ME/CFS. Researchers compared these markers in people with ME/CFS and healthy controls. The study found no link between these particular immune markers and ME/CFS, suggesting that HLA class II antigens are not a defining feature of the condition.

E2 ModerateReviewPEM unclearReview-Narrative

Symptoms and signs of chronic fatigue syndrome.

Komaroff, A L, Buchwald, D·Reviews of infectious diseases·1991

This review summarizes what doctors have learned about chronic fatigue syndrome (ME/CFS) by studying approximately 510 patients. The hallmark features include a sudden illness-like onset, long-lasting exhaustion that severely limits daily activities, and a unique symptom called postexertional malaise—where patients feel much worse after physical or mental activity. Many patients also experience fever, sore throat, swollen lymph nodes, muscle pain, sleep problems, and difficulty concentrating.

Post-Exertional Malaise

Chronic fatigue syndrome: clinical condition associated with immune activation.

Landay, A L, Jessop, C, Lennette, E T et al.·Lancet (London, England)·1991

Researchers used specialized tests to examine immune cells from 147 people with ME/CFS and compared them to healthy people. They found that people with ME/CFS had lower levels of certain immune cells (CD8 suppressor cells) and higher levels of immune activation markers on other immune cells. These differences were not seen in healthy people, contacts of patients, or people with other illnesses, suggesting that immune system activation may be involved in ME/CFS.

E2 ModerateBehavioralPEM not requiredCross-Sectional

A comparative psychiatric assessment of patients with chronic fatigue syndrome and muscle disease.

Wood, G C, Bentall, R P, Göpfert, M et al.·Psychological medicine·1991

This study compared the mental health of 34 patients with ME/CFS to 24 patients with muscle disease. Researchers found that people with ME/CFS were more likely to have psychiatric conditions like depression or anxiety—about 41% had clear psychiatric diagnoses and another 27% had partial ones. In contrast, only about 17% of muscle disease patients had psychiatric conditions. This suggests ME/CFS patients face a higher risk of developing psychiatric issues, though the study doesn't explain why.

Chronic fatigue syndrome: lack of association with hepatitis C virus infection.

Dale, J K, Di Bisceglie, A M, Hoofnagle, J H et al.·Journal of medical virology·1991

Researchers tested whether hepatitis C virus (HCV), a virus that affects the liver, might be a cause of ME/CFS. They compared blood tests from 36 ME/CFS patients and 14 healthy controls. They found that only one ME/CFS patient showed signs of past HCV infection, while none of the healthy people did. This suggests that hepatitis C is not a common cause of ME/CFS.

E2 ModerateCohortPEM unclearCross-Sectional

Frequent double infection with Epstein-Barr virus and human herpesvirus-6 in patients with acute infectious mononucleosis.

Bertram, G, Dreiner, N, Krueger, G R et al.·In vivo (Athens, Greece)·1991

This study looked at 215 patients with infectious mononucleosis to see which viruses were causing their illness. Researchers found that most patients had Epstein-Barr virus (EBV), but many also had human herpesvirus-6 (HHV-6) at the same time. About 40% of patients had active infection with both viruses, and some had a third virus (CMV) as well. Patients were followed for two years to track changes in their virus levels.

Aerobic work capacity in patients with chronic fatigue syndrome.

Riley, M S, O'Brien, C J, McCluskey, D R et al.·BMJ (Clinical research ed.)·1990

This study tested how much physical activity patients with ME/CFS could manage on a treadmill and compared them to healthy people and those with irritable bowel syndrome. Researchers found that ME/CFS patients got tired much faster, had higher heart rates during exercise, and felt like they were working much harder than the other groups—even though they weren't doing as much activity.

Post-Exertional Malaise

The psychiatric status of patients with the chronic fatigue syndrome.

Hickie, I, Lloyd, A, Wakefield, D et al.·The British journal of psychiatry : the journal of mental science·1990

This study looked at whether people with ME/CFS have higher rates of depression and other mental health conditions than the general population. Researchers found that while some patients developed depression after getting ME/CFS, their rates of pre-existing mental illness were similar to everyone else. The study suggests that depression in ME/CFS patients is likely a response to having the illness, not a cause of it.

Immunoglobulin subclass abnormalities in patients with chronic fatigue syndrome.

Wakefield, D, Lloyd, A, Brockman, A·The Pediatric infectious disease journal·1990

This study examined whether people with ME/CFS have unusual patterns in their antibodies—proteins the immune system makes to fight infection. Researchers looked at different types of antibodies in ME/CFS patients compared to healthy people. The findings suggested that ME/CFS patients may have immune system imbalances that differ from the general population.