Myalgic encephalomyelitis / chronic fatigue syndrome (ME/CFS) is as complex as its name is difficult to pronounce. It’s sometimes referred to as simply “chronic fatigue”, but this is just one of its symptoms.

In fact, ME/CFS is a complex neurological disease, recognised by the World Health Organization, that affects nearly every system in the body.

The name refers to muscle pain (myalgia), inflammation of the brain (encephalomyelitis), and a profound, disabling fatigue that rest can’t relieve.

However, the illness’s complexity – and its disproportionate impact on women – means ME/CFS has often been incorrectly labelled as a psychological disorder.

What is ME/CFS?

ME/CFS affects people of all ages but is most commonly diagnosed in middle age. It is two to three times more common in women than men.

While the exact cause is unknown, ME/CFS is commonly triggered by an infection.

The condition has two core symptoms: a disabling, long-lasting fatigue that rest doesn’t relieve, and a worsening of symptoms after physical or mental exertion.

This is known as post-exertional malaise. It means even slight exertion can make symptoms much worse, and take much longer than expected to recover.

This varies between people, but could mean simply having a shower or attending a social event triggers worse symptoms, either immediately or days later.

These symptoms include pain, sleep issues, cognitive difficulties (such as thinking, memory and decision-making), flu-like symptoms, dizziness, gastrointestinal problems, heart rate fluctuations and many more.

For some people, symptoms can be managed in a way that allows them to work. For others, the disease is so severe it can leave them housebound or bedridden.

Symptoms can fluctuate, changing over time and in intensity, making ME/CFS a particularly unpredictable and misunderstood condition.

Not just ‘in your head’

A growing body of scientific evidence, however, clearly shows ME/CFS is a biological, not mental, illness.

Neuroimaging studies have revealed differences in the brain activity and structure of people with ME/CFS, including poor blood flow and lower levels of neurotransmitters (chemical messengers in the nervous system).

Other research indicates the condition affects how the body produces energy (the metabolism), fights infection (the immune system), delivers oxygen to muscles and tissues, and regulates blood pressure and heart rate (the vascular system).

Issues with criteria

To diagnose ME/CFS, a clinician will also exclude other possible causes of fatigue, which can be a lengthy process. A patient needs to meet a set of clinical criteria.

But one of the major challenges in researching ME/CFS is that the diagnostic criteria clinicians use vary worldwide.

Some criteria focus solely on fatigue and include people with alternate reasons for fatigue, such as a psychiatric disorder.

Others are more narrow and may only capture ME/CFS patients with more severe symptoms.

As a result, it can be very difficult to compare across different studies, as the reasons they include or exclude participants vary so much.

Changes to the guidelines

In Australia, doctors often receive little formal education about ME/CFS.

Most commonly, they follow the Royal Australian College of General Practitioners’ clinical guidelines to diagnose and manage ME/CFS. These are based on the Canadian Consensus Criteria which are considered more stringent than other ME/CFS diagnostic criteria.

They include post-exertional malaise and fatigue for more than six months as core symptoms.

However, these guidelines are outdated and rely heavily on controversial studies that assumed the primary cause of ME/CFS was “deconditioning” – a loss of physical strength due to a fear or avoidance of exercise.

These guidelines recommend ME/CFS should be treated with cognitive behavioural therapy – a common psychotherapy which focuses on changing unhealthy thoughts and behaviours – and graded exercise therapy, which gradually introduces more demanding physical activity.

While cognitive behaviour therapy can be effective for some people managing ME/CFS, it’s important not to frame this condition primarily as a psychological issue.

Graded exercise therapy can encourage people to push beyond their “energy envelope”, which means they do more than their body can manage. This can trigger post-exertional malaise and a worsening of symptoms.

In June 2024, the Australian government announced A$1.1 million towards developing new clinical guidelines for diagnosing and managing ME/CFS.

Leading organisations have scrapped the recommendation of graded exercise therapy in the United States (in 2015) and the United Kingdom (in 2021). Hopefully Australia will follow suit.

What can people with ME/CFS do?

While we wait for updated clinical guidelines, “pacing” – or working within your energy envelope – has shown some success in managing symptoms. This means monitoring and limiting how much energy you expend.

Some evidence also suggests people who rest in the early stages of their initial illness often experience better long-term outcomes with ME/CFS.

This is especially relevant after the COVID pandemic and with the emergence of long COVID. Studies indicate more than half of those affected meet stringent clinical criteria for ME/CFS.

In times of acute illness we should resist the temptation to push through. Choosing to rest may be a crucial step in preventing a condition that is much more debilitating than the original infection.

Sarah Annesley, Senior Postdoctoral Research Fellow in Cell and Molecular Biology, La Trobe University

This article is republished from The Conversation under a Creative Commons license. Read the original article.