The 4 main causes of insomnia

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

As other medical sources indicate, the general prevalence of insomnia disorders is 10-15% of the general population. Without going any further, more than 5.5 million annual visits to the doctor are reported in the United States alone for this type of clinical event. It is not for less, because the lack of sleep decreases the productivity of the patient and, in addition, promotes fatigue, irritability, anxiety and cyclical worries.

To address any pathology (be it merely physical or also psychological), it is necessary to know the underlying causes that lead to the symptoms to be solved. Therefore, this time we collect the main causes of insomnia backed by science.

• Related article: "The 7 main sleep disorders"

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 transitory or acute variant (lasts less than 7 days), another of short duration (1-3 weeks) and a chronic variant (more than 3 weeks). Depending on its nature, insomnia can be conciliation, maintenance, early or general awakening.

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

1. Genetics

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

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

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

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

2. Physiology

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

We are not moving on purely conjectural grounds, since multiple studies have analyzed the levels of the hormone cortisol throughout the day in patients with chronic insomnia. Normally, the lowest point for this hormone is in the middle of the night, but it seems that people with sleeping difficulties have higher circulating concentrations in the afternoon / night. There is still much to investigate regarding this issue, but the bases of causality are established.

This makes a lot of sense at a physiological level, since cortisol is the main stress hormone in humans. This is responsible for increasing the level of sugar in the blood (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 of these physiological mechanisms can prevent 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 just a subjective feeling, because as we have seen in the previous section, it can be associated with changes in hormonal concentrations and many other quantifiable events.

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

4. Atmosphere

The physical conditions of the space in which you rest can also lead to acute insomnia events. As obvious as it may seem, poor posture, external noise, a hyperstimulating environment and many other factors can prevent the patient from resting, whether or not they are aware of it.

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

In an experiment conducted in 2017 by the University of Houston, it was shown that a group of volunteers with 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 going to bed During two weeks. This makes it clear that screens hyperstimulate our body.

Insomnia is a multifactorial entity

As you have seen, explaining insomnia is an enormously complex task, since it is an entity that is due to both 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.
• López, C. OR. (2020, December). Sleep macrostructure and cognitive functions in patients with major depression and insomnia. In XIV Postgraduate Congress in Psychology | 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). The insomnia. In Annals of the Navarra health system (Vol. 30, pp. 121-134). Government of Navarra. Health Department.