Medically Unexplained Symptoms (MUS) - What Are They?

Scenarios

Joanne is 38 years old and has been dealing with fatigue for the past two to three years. She recently joined Mentor Clinic after being on the Need a Family Practice Registry for two years. Some days, she feels so tired she has to miss work. As a single mom with two young kids, she often relies on friends for help. Joanne is sure something is wrong. She left her family doctor after a year of tests and specialist visits didn’t find any medical explanation. “It’s not all in my head,” she says.

Bill, 45, developed severe neck pain and headaches eight months ago. He’s a chef at a high-end restaurant. When his pain flares up, he can’t work in the kitchen. He thinks the problem came from lifting heavy pots. Despite normal physical exams, x-rays, scans, and seeing a physiotherapist, chiropractor, osteopath, and massage therapist, he still worries something was missed—like a fracture or even cancer.

Carol is 23 years old and has had on-and-off stomach pain, nausea, and vomiting for over a year. She’s had multiple exams, blood tests, an ultrasound, and a scan, but nothing has been found. Medications haven’t helped much. She is worried because her uncle died of liver cancer. She’s waiting to see a gastroenterologist, but the wait is around 18 months.

MUS

These are all examples of medically unexplained symptoms (MUS)—physical symptoms that don’t have a clear medical cause, even after proper testing. MUS is common and can be frustrating for both patients and healthcare providers. About one in four people who visit a primary care provider with physical symptoms end up with MUS.

You sometimes hear about someone who was told “everything is normal” only to be diagnosed with a serious illness later. This makes patients worry. The healthcare system is under pressure, people feel confused, and trust is low. Patients with MUS often have some background of anxiety, worry, or depression—which is very common in our stressful society. So, when a Nurse Practitioner (NP) or Family Doctor says “all the tests are normal,” it's understandable for patients to wonder, “What are they missing? Wasn’t Uncle Joe told the same thing before he died?”

But it’s not just patients who worry—care providers worry too:

- “What if I’m missing something?”

- “Will they complain about me?”

- “Could I be sued?”

This fear can lead to more tests, medication trials, and referrals to specialists with long wait times. Talking about stress, anxiety, past trauma, or substance use is difficult and takes time. Even though mental health awareness is growing, there’s still stigma. Many people prefer a simple medical answer—a pill, a test, or a scan. As a result, providers may avoid exploring psychological causes to prevent upsetting patients.

This shared anxiety between patients and providers can make MUS worse over time. Symptoms may grow more severe, leading to even more testing. It becomes a cycle—patients suffer, providers feel stuck, and costs increase.

The mind and body are closely connected. Stress and emotions can cause physical symptoms anywhere in the body, but also signs like rashes, fast heartbeat, shaking, or even seizures. These can be very real and disabling. Psychology and biology often work together to cause ongoing symptoms.

Healthcare providers need to consider both physical causes (like infections, cancer, or injuries) and psychological ones (like stress or anxiety). Even if mental health isn’t the main cause, it can still make things worse.

Taking a good history, doing a focused exam, and doing some testing is important—but so is asking about someone’s life, job, relationships, and past experiences.

Most health problems are not purely physical or mental. They’re often a mix.

For example:

·       A person breaks a leg in a biking accident. They need surgery and can’t work for weeks. They have no insurance and care for a parent with dementia. Their muscles weaken, pain continues, and they develop a dependency on pain meds. A simple injury becomes a much bigger issue.

·       A person has seen their NP about 20 different symptoms over two years. No cause has been found, even after many tests. When they show up with symptom number 21, there’s a risk it will be dismissed as MUS—when it might actually be something new and treatable. That’s why providers must stay open-minded and careful.

A benefit of team-based care is having many types of professionals in one place, all offering different views. This helps catch anything that might be missed and can reduce patient worry, wait times, and healthcare costs.

MUS is very common. If your NP or doctor asks about stress or mental health when you’re expecting a CAT scan, try to keep an open mind. They’re trying to look at the full picture—to help find the real cause of your symptoms.