Insomnia is a common sleep disorder, affecting up to one-third of the adult population globally.

It is characterized by difficulty falling asleep, staying asleep, or experiencing non-restorative sleep, causing daytime fatigue, mood changes, and impaired cognitive performance. While there are various triggers for insomnia, including stress, lifestyle, and environmental factors, recent studies suggest that genetics may also play a significant role in the development and severity of insomnia.

What is Insomnia?

Insomnia is defined as a sleep disorder that causes difficulty falling asleep, staying asleep, or waking up too early and not being able to get back to sleep.

Insomnia can be a short-term problem, known as acute insomnia, or a long-term disorder typically lasting three or more months, known as chronic insomnia. The former is often triggered by temporary stressors such as work deadlines, relationship problems, or emotional issues.

The latter is attributed to a combination of factors, including chronic medical conditions, psychological disorders, and medication use.

The Genetics of Insomnia

The connection between genetics and insomnia has been studied for several years, with various research studies pointing towards genetic factors that may increase an individual’s susceptibility to insomnia.

These studies indicate that insomnia can be inherited through genetic mutations that impact the production and regulation of certain brain chemicals that play a critical role in regulating the sleep-wake cycle.

One such complex chemical system responsible for regulating the sleep-wake cycle is the circadian rhythm system. The circadian rhythm is a molecular process that controls our body’s 24-hour internal clock.

Studies have identified that certain genes involved in the regulation of circadian rhythms and the sleep-wake cycle are associated with insomnia. For instance, a missense mutation in the CLOCK gene variant has been linked to increased vulnerability to insomnia and circadian rhythm disorders.

Another gene that has been linked to insomnia is PER1. The PER1 gene plays a critical role in regulating the circadian rhythm and is associated with sleep-wake cycle disturbances.

Emerging studies have shown that single nucleotide polymorphisms (SNPs) within the PER1 gene could be linked to the development of sleep disorders like insomnia.

What is the Polygenic Risk Score?

Polygenic risk score (PRS) refers to a calculation that estimates an individual’s likelihood of developing a particular trait or disease based on their genetic makeup.

This score analyzes multiple genetic variants spread across the genome that have been associated with a particular trait, including insomnia.

The PRS can be calculated using a genome-wide association study (GWAS), which is a large-scale genetic study that analyzes the DNA of thousands of individuals to identify genetic variants associated with a particular condition.

The more genetic variants associated with insomnia that an individual possesses, the higher their PRS, indicating a greater genetic susceptibility to insomnia.

Evaluating the Risk of Insomnia with PRS

A study conducted in 2018 evaluated the role of polygenic risk factors in the development and severity of insomnia.

The researchers collected data from a population-based study of individuals aged 20 to 100 years old, with over 400,000 participants in the study. The study identified 956 genetic variants that were associated with a risk of insomnia. The researchers then calculated the PRS for each participant using these genetic variants and compared it to their insomnia status.

The study found that individuals with a high PRS had a 5.6 times higher risk of developing insomnia compared to individuals with a low PRS.

The researchers also found that the PRS score was directly correlated with the severity of insomnia symptoms, suggesting that genetics may play a key role in the development of insomnia.

Other Factors Involved in Insomnia

While genetics plays a significant role in the development and severity of insomnia, it is important to note that other factors are also involved.

Environmental and lifestyle factors such as work schedules, stress levels, diet, caffeine intake, and exposure to screen time before bedtime can all impact sleep quality and duration.

Other medical conditions, such as sleep apnea, restless leg syndrome, and chronic pain, can also contribute to insomnia. Mental health conditions, such as depression, anxiety, and PTSD, may also increase the risk of developing insomnia.

Treatment for Insomnia

Treatment of insomnia may vary depending on its severity, cause, and underlying medical conditions.

Lifestyle changes such as following a sleep schedule, avoiding caffeine and alcohol, and incorporating relaxation techniques like meditation may help to improve sleep quality. Prescribed medication such as sedatives, antidepressants, and antianxiety medications may be used to treat chronic insomnia.

Therapies such as cognitive-behavioral therapy for insomnia (CBT-I) and sleep restriction therapy may also be employed to treat sleep disorders.

CBT-I is often used to effectively modify negative thoughts and behaviors associated with insomnia, while sleep restriction therapy focuses on restricting the time spent in bed to promote more refreshing sleep.

Conclusion

Insomnia is a common sleep disorder that affects millions of people worldwide. Studies suggest that there may be a genetic link responsible for its development and severity.

Understanding the genetic factors associated with insomnia can potentially lead to the development of novel treatment options that target these genetic variants, thereby improving sleep quality for individuals affected by the disorder.