The impact of COVID-19 on a college freshman sample reveals genetic and nongenetic forms of susceptibility and resilience to stress

COVID-19 lockdown effects on adolescent brain structure suggest accelerated maturation that is more pronounced in females than in males

Adolescence is a period of substantial social-emotional development, accompanied by dramatic changes to brain structure and function. Social isolation due to lockdowns that were imposed because of the COVID-19 pandemic had a detrimental impact on adolescent mental health, with the mental health of females more affected than males. We assessed the impact of the COVID-19 pandemic lockdowns on adolescent brain structure with a focus on sex differences. We collected MRI structural data longitudinally from adolescents prior to and after the pandemic lockdowns. The pre-COVID data were used to create a normative model of cortical thickness change with age during typical adolescent development. Cortical thickness values in the post-COVID data were compared to this normative model. The analysis revealed accelerated cortical thinning in the post-COVID brain, which was more widespread throughout the brain and greater in magnitude in females than in males. When measured in terms of equivalent years of development, the mean acceleration was found to be 4.2 y in females and 1.4 y in males. Accelerated brain maturation as a result of chronic stress or adversity during development has been well documented. These findings suggest that the lifestyle disruptions associated with the COVID-19 pandemic lockdowns caused changes in brain biology and had a more severe impact on the female than the male brain.

Neurobiological basis of stress resilience

A majority of humans faced with severe stress maintain normal physiological and behavioral function, a process referred to as resilience. Such stress resilience has been modeled in laboratory animals and, over the past 15 years, has transformed our understanding of stress responses and how to approach the treatment of human stress disorders such as depression, post-traumatic stress disorder (PTSD), and anxiety disorders. Work in rodents has demonstrated that resilience to chronic stress is an active process that involves much more than simply avoiding the deleterious effects of the stress. Rather, resilience is mediated largely by the induction of adaptations that are associated uniquely with resilience. Such mechanisms of natural resilience in rodents are being characterized at the molecular, cellular, and circuit levels, with an increasing number being validated in human investigations. Such discoveries raise the novel possibility that treatments for human stress disorders, in addition to being geared toward reversing the damaging effects of stress, can also be based on inducing mechanisms of natural resilience in individuals who are inherently more susceptible. This review provides a progress report on this evolving field.

A 2-year mental health follow-up study subsequent to COVID-19

The COVID-19 pandemic has profoundly impacted the mental health and education of college students. This study examined the interrelationships among loneliness, resilience, and COVID-19 fear among college students in Northern Michigan, a region of the United States severely affected by the pandemic. Data were collected from two student cohorts (n = 258), with half surveyed in early 2022 and the other half in mid-2022, two years after pandemic's onset. The Omicron wave peaked in Michigan in January 2022, but by June 2022, cases, hospitalizations, and deaths had significantly declined. Students completed measures of loneliness, resilience, learning difficulty, and psychological symptoms. Key findings are: 1) Participants' fear, loneliness, and academic difficulty decreased over time, reflecting fluctuations in acute situational and emotional states; 2) Unexpectedly, resilience declined from early to mid-2022, suggesting its diminishing protective role under prolonged, pandemic-induced stress; 3) Despite improvements, students continued reporting high academic difficulties. Loneliness, heightened fear, and dampened happiness together contributed to greater academic difficulties; 4) Pre-existing sex differences equalized two years after the pandemic's onset. While modest improvements were noted, enduring academic and mental health impacts signal a need for continued support.