June 3, 2025, 8:58 am | Read time: 7 minutes

Imagine your body losing the ability to sleep—forever. It grows weaker, your mind becomes clouded, and you can no longer regenerate. Fatal familial insomnia is an extremely rare but incurable disease that causes exactly this. Its insidious and mysterious nature both fascinates and chills. Our expert, Prof. Dr. Hartmut Göbel, a neurologist, psychologist, and chief physician at the Pain Clinic Kiel, explains what lies behind this deadly insomnia.

What Is Insomnia and What Types Are There?

Insomnia (sleep disorder) describes the condition where it is difficult to fall asleep, stay asleep, or even sleep at all. There are different forms and manifestations.

• Acute insomnia: Short-term sleep disorder, usually triggered by restlessness, stress, or jet lag.
• Chronic insomnia: Sleep problems occurring at least three times a week for more than three months.
• Psychophysiological insomnia: The link between stress, anxiety, and sleep disorder, the typical vicious cycle of brooding and inability to sleep.
• Secondary insomnia: Sleeplessness as a result of a condition such as depression, anxiety disorder, or chronic pain.
• Paradoxical insomnia: Individuals believe they are not sleeping, although they actually have sleep phases.
• Sporadic fatal insomnia (SFI): A similarly fatal but not genetically inherited form.
• Fatal familial insomnia (FFI): A rare, genetically determined, and fatal form where the brain gradually loses the ability to generate sleep

Are All Types of Insomnia Dangerous?

“Fortunately, not every sleep disorder is automatically life-threatening. Most forms of insomnia can be well treated or disappear on their own. However, it becomes critical when sleep deprivation persists over a long period. Then it can promote cardiovascular diseases, a weakened immune system, and psychological problems,” says Prof. Dr. Göbel.

Fatal Familial Insomnia

Fatal familial insomnia (FFI) is a genetically determined disease. The term “fatal” means “deadly,” “familial” indicates heritability, and “insomnia” describes the main symptom: complete loss of the ability to sleep, where the brain increasingly loses the ability to generate physiologically restorative sleep. The condition was first discovered in 1986 in an Italian family where several members were affected over generations.

What FFI Has to Do with Dementia

“FFI is one of the prion-related dementia diseases, as it is caused by misfolded prion proteins that destroy nerve cells by converting other proteins into the same harmful structure. This creates a fatal domino effect in the brain,” explains Prof. Dr. Göbel. “In addition to severe sleep disorders, affected individuals show typical dementia symptoms such as memory loss, confusion, and personality changes as the disease progresses. The disease thus affects not only sleep but also leads to rapid mental decline.”

Also interesting: Astonishing connection between pulse and dementia

How Does Fatal Familial Insomnia Develop?

FFI is caused by a mutation in the PRNP gene. This gene provides the blueprint for the prion protein (PrP), which plays a role in the nervous system. Due to the mutation, PrP is misfolded and accumulates in the brain, particularly in the thalamus, which controls the sleep-wake cycle. The deposits lead to the death of nerve cells.

The Symptoms of FFI

• Progressive insomnia with initially shortened deep sleep phases, then complete inability to sleep.
• Autonomic dysfunction such as irregular blood pressure, excessive sweating, fever, and rapid heartbeat.
• Neuropsychiatric symptoms such as anxiety, hallucinations, irritability, and eventually dementia-like conditions.
• Coordination disorders when walking and moving (ataxia).
• Involuntary muscle twitches (myoclonus), which occur especially in advanced stages of the disease and further impair nighttime behavior.

What Makes This Sleep Disorder So Insidious?

The gradual onset and nonspecific symptoms make diagnosis difficult. The disease often initially disguises itself as burnout, depression, or anxiety disorder. It also initially seems harmless because sleeplessness is considered annoying but not dangerous. However, when the body can no longer regenerate without sleep, it leads to relentless physical and mental decline.

Who Is Affected?

“Those affected are primarily people with a familial, genetic predisposition. FFI is inherited in an autosomal dominant manner. This means that if one parent carries the altered gene, there is a 50 percent chance of passing it on,” says Prof. Dr. Göbel. “The first symptoms usually appear between the ages of 30 and 60.”

Course of the Disease

Although FFI is rare, its course is well documented medically. The entire course of the disease averages seven to 73 months after the onset of symptoms and goes through four phases.

1. Initially, sleep disturbances occur, accompanied by so-called autonomic disorders such as sweating, rapid heartbeat, blood pressure fluctuations, and fever.
2. In the second phase, insomnia increasingly worsens. Affected individuals suffer from hallucinations, panic attacks, and nighttime confusion.
3. In the third phase, they eventually lose the ability to sleep completely. Cognitive deficits such as speech disorders, memory loss, and coordination problems are added.
4. The final phase is characterized by complete physical and mental decline, eventually leading to coma and death.

Chances of Recovery and Life Expectancy

There is currently no cure, and therapies can only slightly slow the progression.

Treatment

Medical

“The therapy is primarily symptomatic and includes sleep-inducing medications, antidepressants, and sedatives, which usually show only limited effectiveness. In addition, experimental approaches such as immunotherapies and so-called prion inhibitors are being researched, but so far, without breakthrough success. Therefore, purely palliative treatment is often the focus, which means alleviating pain, anxiety, and other distressing symptoms, as well as providing support in the final phase of the disease,” explains Prof. Dr. Göbel.

What You Can Do Yourself

In cases of familial predisposition, early genetic counseling is advisable to better assess risks. Seek psychological support as an affected person or relative to cope with the emotional burden.

What Happens if FFI Is Not Treated?

Since there is no effective causal therapy, the disease ends fatally—regardless of medical measures. Without palliative support, however, the course can be particularly agonizing. Therefore, alleviating symptoms and providing support during the dying process is essential.

Can the Disease Be Prevented?

Since it is a genetic disease, its development cannot be prevented. However, if there is a known familial burden, a genetic test can provide clarity, and genetic counseling is advisable, especially for couples wishing to have children.

First Warning Signs

Early warning signs can appear gradually but should be taken seriously, especially with familial predisposition. These include sudden and persistent insomnia despite physical exhaustion, as well as unexplained rapid heartbeat, excessive sweating, or anxiety without an apparent cause. Increasing forgetfulness or coordination difficulties can also be warning signs. If you notice such symptoms in yourself, you should seek a neurological specialist clinic early to clarify possible causes.

Is It True That Sleep Disorders Are Psychological Disorders?

Many forms of insomnia are indeed psychologically based, such as those caused by stress, anxiety, or depression. FFI, however, is an organic neurodegenerative disease, meaning a physically caused disease of the nervous system.

Self-test: Could I Be Affected?

• Has anyone in my family suddenly lost the ability to sleep?
• Was there a rapidly progressing dementia in my family?
• Do I suffer from unexplained sleep problems and distressing neurological symptoms?

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Conclusion

Fatal familial insomnia is one of the most puzzling and tragic diseases of modern medicine. It is extremely rare but highly complex and a shocking example of how central sleep is to our lives. Those affected fight not only against physical and mental decline but also against the complete loss of a basic human need: sleep. Therefore, it is all the more important to be vigilant with familial predisposition.