Insomnia is a problem that affects millions of people around the world and to solve it, it is important to first know what are the types of insomnia that exist. Although the consequence is the same in all cases (not being able to sleep) the causes can be different and therefore, the solution.
Despite the high prevalence, the considerable heritability of insomnia and the identification of genes that confer an associated risk, it has been difficult to characterize insomnia consistently with respect to cognition, mood, family history, events of life, personality, among other factors. \
Such inconsistencies suggest unrecognized subtypes of insomnia disorder and delay progress in understanding their underlying mechanisms, an understanding that could improve interventions.
Using thousands of volunteers, a research team from the Netherlands Institute of Neuroscience (NIN) conducted a study on insomnia whose results revealed why it has been so difficult to find consistent brain mechanisms behind the problem and treatment effects.
“While we have always considered that insomnia is a disorder, it actually represents five different disorders. The underlying brain mechanisms can be very different,” says Dr. Tessa Blanken, an academic in the Department of Sleep and Cognition of the NIN.
The researchers identified subtypes with a vision that surpasses traditional sleep complaints. For this purpose, the team evaluated dozens of questionnaires about personality traits that are known to be rooted in the structure and function of the brain. By studying the profiles of personality traits, the team has identified 5 subtypes of insomnia.
People with Type 1 insomnia have a high score on many distressing traits, such as neuroticism, depression or tension. People with types 2 and 3 are less distressed and were distinguished by their low sensitivity to reward (weak responses to pleasurable emotions). Types 4 and 5 experienced even less distress and differed in the way their sleep responded to the stressful events of life.
The volunteers who were examined again after five years, mostly retained their own type of insomnia, suggesting an anchoring in the brain.
The establishment of subtypes has clinical relevance. The effectiveness of the treatment with sleeping pills or cognitive behavioral therapy differed according to the type, and the risk of developing a depression varied dramatically.