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When the Brain Can't Sleep: Understanding Fatal Familial Insomnia

Jessica Chen

Introduction

Sleep is one of the most important necessities for human survival and plays a crucial role in both physical and mental health. It is not optional—it is essential for mental health, repairing brain function, lowering stress levels, and regulating hormones. Without sleep, the human’s ability to concentrate would be negatively affected, the risks of developing heart diseases would increase, and the immune system would weaken. But imagine one day, you come home from a long, exhausting day and finally get into bed, expecting to fall asleep, but sleep never comes no matter how hard you try. In rare cases, this could be caused by a neurological condition that prevents the brain from sleeping, called Fatal Familial Insomnia. Although it affects only a small number of families in the world, studying FFI helps us understand how neurodegenerative diseases affect the brain.

What is Fatal Familial Insomnia?

Fatal Familial Insomnia (FFI) is an extremely rare prion disease that affects an individual’s brain and central nervous system, causing the inability to sleep. This is caused by a mutation or change in the prion protein gene (PRNP), which is essential for making prion proteins (PrPC) in the brain's thalamus to regulate sleep. When the gene is mutated, the protein misfolds and becomes toxic to the cells in your nervous system, causing damage to the brain’s tissues and the loss of neurons. Additionally, FFI is autosomal dominant, which requires only one parent to pass down the mutated gene to inherit the condition. It is important to know that FFI is a degenerative disease, meaning that the brain will progressively lose its ability to enter sleep cycles and symptoms will gradually worsen. As of today, the disease has no cure and will lead to death; however, scientists are continuing to research treatment options to slow the progression of symptoms and reduce the buildup of abnormal prion proteins.

Symptoms

Early on, symptoms of Fatal Familial Insomnia (FFI) resemble symptoms of other neurodegenerative diseases such as Dementia and Alzheimer’s. Individuals usually experience insomnia as their first symptom, finding it difficult to sleep at first. These symptoms will start subtly and progressively worsen over the next few months. As the disease progresses, additional symptoms may be encountered:

• Tachycardia and high blood pressure.

• High anxiety levels.

• Loss of memory, thoughts, speech, and behaviors.

• Severe weight loss.

In some cases, individuals may experience symptoms that are similar to those of Parkinson’s disease, such as double vision, rapid/jerky eye and muscle movement, and difficulty swallowing.

Diagnosis 

Since Fatal Familial Insomnia (FFI) is extremely rare, many doctors may not suspect it at first. However, if the symptoms are reviewed and approved to take tests, several tests could be used to confirm the diagnosis:

• Polysomnography: a test that tracks abnormal patterns in an individual when sleeping.

• Neuroimaging scans: Positron Emission Tomography (PET), Computed Tomography (CT), or Magnetic Resonance Imaging (MRI).

• Electroencephalogram: a test that tracks the electrical activity of your brain.

• Cerebrospinal Fluid Analysis: a test that analyzes cerebrospinal fluid to determine if it contains abnormal substances.

• Molecular genetic testing: a test that detects the targeted, abnormal variant in the PRNP gene.

Treatments

While there is currently no cure for Fatal Familial Insomnia (FFI), there are many treatments that can extend FFI patients’ lives and allow comfort and relief when experiencing symptoms. There are several treatments:

• Taking clonazepam to prevent twitchy muscle movements

• Taking anti-seizure medications 

• Hospice care

• Psychosocial therapy

Many researchers are actively studying for new treatments and designing therapies to prevent abnormal prion proteins. One study has confirmed that Doxycycline, an antibiotic, has helped extend the life of people diagnosed with FFI. It is also important to provide nutritional support, as FFI patients will have difficulty swallowing food and liquids. Therefore, there may be a need for a feeding tube.

How common is Fatal Familial Insomnia?

Prion diseases are extremely rare, so Fatal Familial Insomnia (FFI) is not a common disease and only affects 1 to 2 people out of a million worldwide every year, and approximately 50 to 70 families carry the genetic mutation that causes the condition. Additionally, FFI affects individuals of all genders, usually between the ages of 45 and 50 years old, and has been found in many areas, mainly in Europe and Asia. Because FFI is not common, it is very difficult to diagnose it and many doctors may mistake it for other neurological diseases. It also makes it harder for scientists to develop treatments and study the disease.

Conclusion and Why Fatal Familial Insomnia Is Significant

Fatal Familial Insomnia is indeed one of the most devastating neurological diseases as it will gradually destroy the brain's ability to sleep, affecting both people’s mental and physical health. It is understandable when emotional stress takes over families as they care and grieve for their loved ones. Although there is currently no cure, there are ongoing researchers looking for potential treatments. Studying FFI is not only helpful for the few families in the world struggling with the disease, but it also offers crucial information on why sleep is important for the human body and how the brain controls sleep. 

Works Cited

Khan, Z., & Bollu, P. C. (2019, June 3). Fatal Familial Insomnia. Nih.Gov; StatPearls Publishing. https://www.ncbi.nlm.nih.gov/books/NBK482208/ 

Cleveland Clinic. (2023, April 28). Fatal Familial Insomnia: Symptoms, Causes & Outlook. Cleveland Clinic. 

https://my.clevelandclinic.org/health/diseases/25001-fatal-familial-insomnia 

National Organization for Rare Disorders. (2018). Fatal familial insomnia - NORD (national organization for rare disorders). NORD (National Organization for Rare Disorders); NORD. https://rarediseases.org/rare-diseases/fatal-familial-insomnia/ 

Fatal Familial Insomnia | Baptist Health. (2026). Baptist Health. https://www.baptisthealth.com/care-services/conditions-treatments/fatal-familial-insomnia 

Summer, J. (2021, October 29). Fatal Insomnia. Sleep Foundation. https://www.sleepfoundation.org/insomnia/fatal-insomnia