The 4 main causes of insomnia

These are the causes of insomnia, from genetic, physiological, environmental and psychological.

Insomnia is a very common pathology in the general population.. This experience is defined as a sleep disorder consisting of the inability to initiate sleep, to maintain it over time or, failing that, an inability to achieve a quality of rest adequate to restore the patient's energy and normal wakefulness. According to epidemiological studies, approximately 30% of the adult population presents one or more symptoms of insomnia.

As indicated by other medical sources, the overall prevalence of insomnia disorders is 10-15% of the general population. Without going any further, more than 5.5 million annual physician visits are reported in the United States alone for this type of clinical event. This is not surprising, since lack of sleep reduces the patient's productivity and, in addition, promotes fatigue, irritability, anxiety and cyclical worries.

To address any pathology (whether purely physical or psychological), it is necessary to know the underlying causes that lead to the symptoms to be solved. For that reason, in this opportunity we gather the main causes of the insomnia supported by the science.

What are the causes of insomnia?

First of all, it is necessary to emphasize that there are several types of insomnia. Based on its duration, we can distinguish a transient or acute variant (lasts less than 7 days), another of short duration (1-3 weeks) and a chronic (more than 3 weeks). Depending on its nature, insomnia can be of conciliation, maintenance, early awakening or general.

In order to address this series of clinical pictures in any of its variants, it is necessary to know the etiological causative agent. Below, we present to you all the fronts that can favor insomnia in patients.

1. Genetics

Epidemiological studies show significant evidence that insomnia is moderately heritable. It is estimated that the range of heritability of the characteristics that promote its onset is approximately 22 to 25%. We go even further, since it has been possible to isolate genes that cause sleep deprivation in Drosophila flies, which have a pattern of insomnia similar to that of humans.

One of these genes is PER3, part of the group of genes responsible for maintaining the correct circadian rhythm in living beings. In experimental settings, mutations in PER3 have been associated with a tendency to morningness and generalized anxiety.. This type of data shows that, without a doubt, genetics must play a more or less relevant role in the development of insomnia.

On the other hand, it should be noted that there is an inheritable fatal disease whose main clinical sign is persistent insomnia. This pathology is known as "fatal familial insomnia" and is due to a mutation of the PRNP gene, located on human chromosome 20. It is an autosomal dominant pathology, i.e. the coding gene is located on a non-sex chromosome and is expressed independently of the complementary allele.

• You may be interested in "What is the genetic code and how does it work?".

Physiology 2.

Insomnia has historically been associated with hyperarousal: a state of increased activity at the somatic, cognitive and cortical levels.. People with insomnia often experience abnormal arousal in the central and peripheral nervous system, which can be measured by physiological parameters such as increased cortisol concentration, accelerated heart rate and changes in brain bioelectrical activity.

We are not moving into purely conjectural terrain, since multiple studies have analyzed the concentrations of the hormone cortisol throughout the day in patients with chronic insomnia.. Normally, the lowest point of this hormone is in the middle of the night, but it appears that people with sleep difficulties have higher circulating concentrations in the afternoon/evening. There is still a lot of research to be done in this area, but the basis for causality is established.

This makes a lot of sense on a physiological level, as cortisol is the main stress hormone in humans. It increases Blood sugar levels (glycemia), suppresses immune activity and promotes the metabolism of fats, proteins and carbohydrates, among many other things. In short, it prepares us to fight or flee in dangerous situations. As you can imagine, all these physiological mechanisms can impede rest.

3. Psychological disorders

When exploring this type of pathology, it is necessary to understand that the physical and behavioral go hand in hand. Stress is not only a subjective feeling, because as we have seen in the previous section, it can be associated with changes in hormone concentrations and many other quantifiable events.

Therefore, it is more than clear that insomnia is related to psychological illnesses and, therefore, to specific neuronal or metabolic events.. For example, 90% of patients with major depressive disorder suffer from insomnia, 33% of panic attacks occur at night and up to 80% of schizophrenic people suffer from sleep problems. With these data in hand, it is impossible not to establish an unequivocal correlation between mental disorders and difficulty resting.

4. Environment

The physical conditions of the space in which one rests can also be conducive to acute insomnia events.. As obvious as it may seem, poor posture, external noise, a hyper-stimulating environment and many other factors can prevent the patient from resting, whether the patient is aware of it or not.

A curious case is that of cell phones and other devices in constant use. Melatonin is a hormone produced naturally by multiple living beings that is associated with the sleep cycle in humans, but it appears that exposure to bright light before bedtime reduces its synthesis.

In an experiment conducted in 2017 by the University of Houston, it was shown that a group of volunteers wearing special glasses (which block the incidence of blue light) produced up to 58% more melatonin than the control group if they wore them three hours before bedtime for two weeks. This makes it clear that the screens hyperstimulate our organism.

Insomnia is a multifactorial entity

As you have been able to see, explaining insomnia is an enormously complex task, as it is an entity that is due to genetic, physiological, psychological and environmental factors. As science advances and studies report more information, we are increasingly able to link more emotional disorders to quantifiable physiological patterns.

Bibliographic references:

• Hirotsu, C., Tufik, S., & Andersen, M. L. (2015). Interactions between sleep, stress, and metabolism: From physiological to pathological conditions. Sleep Science, 8(3): pp. 143 - 152.
• Kaur, H., Spurling, B. C., & Bollu, P. C. (2020). Chronic insomnia. StatPearls [Internet].
• Lind, M. J., & Gehrman, P. R. (2016). Genetic pathways to insomnia. Brain sciences, 6(4): 64.
• Lopez, C. O. (2020, December). Sleep macrostructure and cognitive functions in patients with major depression and insomnia. In XIV Congreso de Posgrado en Psicología | UNAM| 2020.
• Roth, T. (2007). Insomnia: definition, prevalence, etiology, and consequences. Journal of clinical sleep medicine, 3(5 suppl): S7-S10.
• Sarrais, F., & de Castro Manglano, P. (2007). Insomnia. In Anales del sistema sanitario de Navarra (Vol. 30, pp. 121-134). Government of Navarra. Department of Health.