Evening chronotype individuals show higher vulnerability to anxiety and related disorders

The study shows that the greater vulnerability of individuals with evening chronotype (individual with the propensity to be more productive at night or at dawn) to anxiety and related disorders may be mediated by impaired emotional learning.

Do you know what your chronotype is? Chronotypes are our circadian preference profiles, that is, they refer to the differences in performance that each person has in relation to periods of sleep and wakefulness throughout the 24 hours of the day. We can be morning type (if we prefer to get up early and perform well in activities that start in the morning), evening type (if we are more productive at night or early in the morning and prefer to stay up later), or intermediate (if we We easily adapt to morning and afternoon schedules).

Circadian rhythms have been increasingly studied because they can help understand the onset of mental disorders such as anxiety and post-traumatic stress disorder (PTSD). In this sense, the researchers Chiara Lucifora, Giorgio M. Grasso, Michael A. Nitsche, Giovanni D’Italia, Mauro Sortino, Mohammad A. Salehinejad, Alessandra Falzone, Alessio Avenanti and Carmelo M. Vicario resorted to the classic Pavlovian paradigm of the conditioning of the fear. study the neurocognitive basis of the association between chronotype and fear responses in healthy humans.

In the article “Enhanced fear acquisition in individuals with evening chronotype. A virtual reality fear conditioning/extinction study,” published in the Journal of Affective Disorders, August 2022, researchers from the Università Degli Studi di Messina and the Università di Bologna (Italy), Leibniz Research Center for Working Environment and Human Factors (Germany) and the Catholic University of Maule (Chile) explain that they used 40 participants recruited from students at the University of Messina, 20 with evening chronotype and 20 controls (i.e. intermediate chronotype) to complete a 2-day Pavlovian fear learning and extinction virtual reality task.

To our knowledge, only one study (Pace-Schott et al., 2015) to date explored the role of chronotypes in fear acquisition and extinction in healthy humans, but did not test intermediate chronotypes, the ideal control group already which are the most frequent chronotype in the population (Partonen, 2015).”

Carmelo M. Vicario, Researcher, BIAL Foundation

The results obtained in the two groups showed a greater fear acquisition response in evening chronotype individuals, compared to intermediate chronotype participants, confirming previous evidence associating the evening chronotype with a higher risk of anxiety disorders. (Alvaro et al., 2014; Park et al., 2015) and PTSD (eg, Hasler et al., 2013; Yun et al., 2015).

“This study provides new insights into the influence of circadian rhythms on cognitive and affective processes, suggesting that the increased vulnerability of the evening chronotype to anxiety and related disorders may be mediated by altered fear acquisition,” says Vicario. .