Genealogy, or your family’s genetic history, isn’t necessarily the first thing that comes to mind when looking to understand sleep and sleep disorders. It’s far more common to consider environmental factors such as diet and stress. An often overlooked factor contributing to sleep quality and disturbance is whether certain sleep issues are inherited. As scientists explore the link between sleep and genetics, new research suggests that heredity plays a strong role in sleep/wake cycles and related disorders.
This guide will explore the connection between genealogy and various sleep disorders in order to understand how certain shared genes within a family can signal a predisposition towards certain sleep illnesses.
The Genetics of Sleep
Even now, scientists are still trying to understand why humans sleep. It’s a complicated subject for which there is no one definite answer. Because there is still a lot to know about sleep illnesses and how long we need to sleep, it’s a blind spot that makes it tough to comprehend and universally treat sleep disorders.
In 2017, Washington State University researchers uncovered an important gene linked to sleep known as gene FABP7. The group successfully determined that mutations to this specific gene led to poor sleep quality.
Scientists looked at genes in mice that changed expression over the day during the sleep/wake cycle and found that the FABP7 gene changed significantly in the brains of these mice. Additionally, by removing the gene from mice, they observed that the animals slept more fitfully than those with an intact FABP7 gene.
When affiliated scientists in Japan repeated this research with 300 human volunteers, they found those with a mutated FABP7 gene also slept fitfully, frequently waking during the night.
Studies like this are crucial to proving that poor sleep quality isn’t solely a factor of one’s environment, behaviors, or even non-sleep-related health issues. Additionally, if some sleep disorders are directly tied to genealogy, it opens the door to understanding poor sleep, and which genes could play a role in the development of certain sleep illnesses.
Inherited Mental and Physical Illnesses
Before looking further into sleep disorders that run in families, it’s crucial to understand other inherited traits with the potential to impact your sleep. Certain mental and physical health issues are proven to cause sleep problems; and as these illnesses could be inherited, sleep problems might arise from genetic defects that aren’t directly linked to sleep genes.
Understanding how these non-sleep related factors affect one’s health is important in ruling out other environmental or genetic factors before linking them to sleep genes.
Below are hereditary-linked mental and physical ailments with the potential to cause sleep-related issues.
Studies show that obesity often interferes with your overall sleep patterns. The consequences include reduced insulin resistance and the development of sleep apnea. Just as obesity can influence sleep, poor sleep quality itself is blamed for vulnerability to becoming obese.
Often obesity is thought of as a result of one’s environment and habits, but scientists found that some people are genetically predisposed to gaining weight. If your parents or grandparents struggled with excessive weight gain, it’s possible for them to pass down genes that make you more likely to become obese.
Although such individuals are at a higher risk of excess weight gain, it’s not absolutely definite that they’ll become obese. The solutions to these issues include a focus on nutrition, creating a sufficient calorie deficit to lose weight, and getting at least 30 minutes of physical exercise daily.
Anxiety & Depression
When suffering from depression or anxiety, getting a good night’s sleep can be especially challenging. Nearly 40 percent of patients seeking help for sleep disorders have a psychiatric condition.
Mental health issues are more common than many realize, as one in every five Americans is currently living with a mental illness. While anxiety and depression can contribute to sleep problems, it’s possible for such issues to develop as a result of chronic sleep issues. Additionally, a family history of these conditions can increase your likelihood of developing anxiety or depression in your lifetime. However, while some patients are part of families that exhibit regularly exhibit symptoms of anxiety and depression, others have no family history.
Attention-deficit/hyperactivity disorder or ADHD is a condition that you might associate with energetic children who struggle to concentrate in school. In reality, the condition follows some ADHD sufferers well into adulthood. Research shows that the disorder can run in families; those with parents or siblings that have ADHD are more likely to develop the condition themselves.
As much as 50 percent of those with ADHD report trouble sleeping, and nearly 75 percent of adults with ADHD experience insomnia. It’s hard to treat ADHD-related sleep disorders because often treatments for ADHD can cause sleep-related health issues. Medical professionals now know that medicines such as Adderall, Dexedrine, or Focalin, all of which are stimulants, cause insomnia or otherwise disrupt sleep patterns.
One alternative for ADHD patients includes cognitive behavioral therapy (CBT). CBT is a form psychotherapy which allows you to recognize thought patterns well enough to better manage them, allowing you to minimize hyperactive or anxiety-related thoughts prior to bedtime.
Other options include meditation and deep breathing exercises.
Whether a person’s vulnerability to drug and alcohol addiction stems from nature or nurture continues to be a source of debate, though scientists believe the likelihood of developing an addiction is either moderately or very strongly linked to your genes. When it comes to addiction and sleep, studies show that drug and alcohol use does affect sleep.
Alcohol is a depressant, meaning it inhibits functions of the central nervous system, causing symptoms such as drowsiness. Because of this, up to 20 percent of Americans admit to using alcohol as a sleep aid. Insomniacs are likely to consume alcohol in an effort to get some rest. Despite the nature of alcohol, it’s more likely to cause sleep problems than it is to treat them.
Research shows that addiction to drugs or alcohol often results in comorbid sleep disorders or disorders where the symptoms of addiction lead to sleep-related issues which further encourages sufferers to self-medicate in harmful ways. In addition to the negative health risks associated with excessive drug or alcohol abuse, there’s also an increased risk of multiple health problems brought on by chronic sleep disorders.
Understandably, chronic pain makes it difficult to get comfortable enough to fall or stay asleep. Some conditions are much worse than others, but all can lead to poorer sleep quality.
- Migraines: Migraines are extreme headaches often accompanied with symptoms such as nausea or stomach pain, sensitivity to light, vertigo, and fatigue. Migraines can last anywhere from a few hours to a few days. They tend to run in families, and scientists even discovered that migraine sufferers share a gene mutation in common with those diagnosed with advanced sleep phase syndrome.
- Fibromyalgia: People with this condition feel pain more acutely than others. Because fibromyalgia tends to run in families, it’s plausible that genetic factors determine how likely someone is to develop the condition. However, scientists have yet to identify the genetic basis for fibromyalgia. Genes aside, individuals can develop fibromyalgia due to infection or illness.
- Arthritis: Much of the time, arthritis gets heavily associated with painful inflammation and stiffness of the joints. Rheumatoid arthritis can cause inflammation in unexpected places such as the eyes, lungs, and blood vessels. The condition develops in mid to late adulthood and is punctuated by periods of severe symptoms or “flare-ups.” These periods are usually followed by periods without any symptoms (remissions).
- Menstrual Cramps: In the days before a woman’s period starts, hormone levels drop, which can cause insomnia. Additionally, women who experience cramps, nausea, and bloating during their menstrual cycle will often struggle to feel comfortable enough to sleep. Methods of coping with cramps include taking pain medication or using a heat pad or bottle filled with hot water to relieve symptoms. Doctors recommend sleeping in the fetal position as it takes the pressure off the abdominal muscles.
Genealogy and Sleep Disorders
An estimated one-third of the population copes with sleep disorders. In addition to social, economic, and medical issues, scientists now believe these disorders are passed down genetically.
Despite this conclusion, the amount of published research on genealogy and sleep is somewhat rare, especially in humans. For now, much of the research is concentrated on sleep behaviors in mice, dogs, and other animals. Yet as scientists pursue the groundbreaking research into how genes control sleep, they learn more about which disorders are inherited and open the door to better treatment options for those with sleep-related illnesses.
Read on to learn about sleep disorders and the ways in which they might be genetically passed down.
Dyssomnias (including insomnia and hypersomnias)
Dyssomnias cover a wide range of sleep disorders that involve a person’s ability to fall asleep, stay asleep, or avoid sleeping excessively.
The most commonly known dyssomnia is insomnia, which affects up to 20 percent of Americans at any given time. You’re likely suffering from insomnia if you have trouble falling asleep at least three nights per week. Short-term insomnia is a condition experienced for less than three months while chronic insomnia stretches on for longer. For chronic sufferers, the associated health risks are severe, such as obesity, diabetes, and cardiovascular disease — including an increased risk of heart attacks. Insomnia sufferers are also 2.8 times more likely than the rest of the population to die in a car crash.
On the opposite end of the spectrum are hypersomnia sufferers, people who sleep more than 9 hours in a 24 hour period. One of the main symptoms of the condition is daytime sleepiness. While it might not be as talked about as insomnia in society, nearly half of adults are thought to experience hypersomnia at some point in their lives.
Another well-known, though often misunderstood dyssomnia is narcolepsy, Those with the disorder may get the recommended amount of sleep and feel otherwise rested upon waking up but still experience excessive sleepiness and an uncontrollable urge to sleep throughout the day. It’s quite rare, with less than 200,000 Americans reportedly suffering from the disorder.
Other dyssomnias include breathing-related sleep disorders such as sleep apnea.
It’s possible for you to develop a dyssomnia-related sleep disorder during your life due to factors ranging from medication side-effects to hormone fluctuations in pregnant women. But research demonstrates that some individuals are predisposed to dyssomnia conditions because of a family history.
A 1972 study looked at the families of patients diagnosed with hypersomnia or narcolepsy. The family members responded to a series of questionnaires and underwent clinical examinations. The results showed that in more than one-third of these cases, family members had similar sleep-related issues. These type of studies point towards a very real genetic link to a raised predisposition for developing dyssomnias.
Additionally, scientists now know that sleep/wake patterns are genetically regulated, making it easier to theorize that certain dyssomnias are the result of familial genes rather than medication side-effects or poor sleep hygiene.
Because of this, genetic factors should be taken into consideration when attempting to understand why someone might develop insomnia, hypersomnia, or a related sleep disorder during their lifetime.
Parasomnias are sleep disorders that share common symptoms with dyssomnias such as daytime sleepiness and the inability to concentrate. However, while dyssomnias are more likely to affect your ability to fall asleep or readily awaken, parasomnias represent abnormalities and unwanted behaviors that occur between the sleep stages.
Upwards of 66 percent of adults will experience parasomnia at some point in their lifetime, and around 12 percent will have five or more experiences. The likelihood of developing at least one parasomnia can be elevated by traumatic experiences, chronic pain, alcohol consumption, or as a side effect of certain medications such as stimulants, sedative-hypnotics, neuroleptics, trazodone, and zolpidem (Ambien).
There’s evidence that parasomnia disorders run in families. One 2008 study looked at the association of parasomnias and dyssomnias between eight-year-old twins in an effort to estimate genetic and environmental influences on their condition. The research revealed that while shared genes can predispose someone towards developing a parasomnia disorder, it also showed that family members might not develop the same type of disorder. One could develop a parasomnia while another suffered from dyssomnia disorders. Environmental factors can play crucial roles in determining what type of parasomnia develops within a family.
In understanding how familial genes predispose a person towards developing sleep disorders, these studies might be able to predict what types of stressors, side-effects, or other environmental conditions cause you to develop one parasomnia over another.
Circadian Rhythm Disorders
The circadian rhythm is the means by which your body naturally regulates your daily sleep and wake cycle. Circadian rhythm disorders are sleep disorders that repeatedly interfere with when you sleep and wake up. Symptoms include the inability to fall asleep, difficulty staying asleep, or daytime fatigue, as well as the inability to concentrate.
People who are blind or work the night shift are among the most vulnerable to developing a circadian rhythm disorder. It’s also possible to experience a temporary disorder called jet lag after rapidly traveling across time zones by airplane.
In recent years, scientists have made huge steps in understanding which genes are directly tied to our circadian rhythm and how those genetic mutations can not only disrupt our sleep/wake patterns but cause other mental illnesses to develop alongside sleep disorders.
For instance, mood spectrum disorders such as bipolar disorder and depression are often accompanied by altered circadian rhythms. Some researchers believe that altered circadian rhythms might serve as biological markers for these mood disorders. Scientists have thus far found connections between circadian genes such as CLOCK, ARNTL1, NPAS2, PER3 and NR1D1 and bipolar disorders. To a lesser extent, these genes also yielded some connection to the presence of depression and seasonal affective disorders.
These new studies reveal how disruptions to your daily circadian rhythm are related not only to sleep disorders but can cause various non-sleep related health ailments.
Your Genetics and How Much Sleep You Need
Not everyone requires the same amount of sleep to be at their best the next day. Despite the common claim that eight hours is best, the CDC recommends anywhere from seven to nine hours of sleep for adults.
Your genes are another crucial factor in determining the right amount of sleep. A much-cited 2018 study determined how genes can factor into how much sleep you need. Researchers identified a human gene called DEC2 that plays a crucial role in the body’s sleep/wake cycle. Mutations in the DEC2 gene can cause people to have abnormally short periods of sleep.
In 2009, scientists examined a family that shared a mutation in the DEC2 gene, all of whom tended to fall asleep between 11 p.m. and midnight but all woke up around 5 a.m. in the morning. The family in the study didn’t intentionally try to sleep so little; instead, their low sleep requirement represented their natural sleep cycle. Despite their abnormally short amount of sleep, which averaged 6.25 hours a night, they functioned in much the same way as those receiving the recommended 7-9 hours.
The condition is indeed unusual, affecting less than five percent of the general population.
What’s interesting about the DEC2 gene is that it regulates circadian rhythms in different animals, including the fruit fly, a creature that’s at least 40 million years old. The presence of this gene in fruit flies supports the theories that sleep/wake patterns are much older than even early man, and that the need for a circadian rhythm is much older and more complex than previously realized. Particularly as scientists find that this particular “short-sleeper” mutation allows for much more efficient sleep than what the average sleeper currently gets.
Scientists are still trying to identify subjects with an abnormal DEC2 gene; it’s believed that understanding genetic mutations of this kind and their familial links can better help researchers determine ways to develop treatments for those with predispositions to sleep disorders.
Aspects of sleep continue to remain a mystery, but research into ties between genealogy and sleep have helped scientists begin to understand how certain disorders arise from one’s environment and which conditions might have familial ties. While additional discussion and research into genealogy and sleep are needed, it’s important remember that not all sleep disorders are inherited. Even if multiple close relatives suffer from sleep-related issues, it doesn’t automatically mean that you’ll deal with the same sleep problems yourself. Nevertheless, this area of research represents groundbreaking opportunities for scientists to better understand why we humans experience sleep illnesses, as well as how a predisposition to certain sleep disorders might determine which treatment options are more likely to succeed.
If you’ve found this guide helpful and want to learn more about sleep health and disorders, check out additional links below: