Night owls show increased acquisition of fear, which may increase the risk of developing anxiety

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

Chronotypes are our circadian preference profiles; that is, they refer to the differences in each person’s performance with respect to periods of sleep and wakefulness throughout the 24 hours of the day. We can be the morning type if we prefer to get up early and perform well in activities that start in the morning; evening types if we are more productive at night or at dawn and prefer to stay up later); or intermediate if you easily adapt to morning and evening schedules.

Circadian rhythms are increasingly studied because they can help understand the onset of mental disorders such as anxiety and post-traumatic stress disorder (PTSD). In this vein, 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 have consulted the classical Pavlovian paradigm of conditioning of fear to study the neurocognitive basis of the association between chronotype and fear reactions in healthy humans.

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

“To the best of our knowledge, only one study to date has explored the role of chronotypes on the acquisition and extinction of fear in healthy humans, but did not test intermediate chronotypes, the control group ideal because they are the most frequent chronotype in the population.” explains researcher Carmelo M. Vicario.

The results obtained in both groups showed a higher fear acquisition response in individuals of the evening chronotype than in participants of the intermediate chronotype, confirming previous evidence that associated the evening chronotype with a higher risk of disorders. anxiety and PTSD.

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

Provided by the BIAL Foundation