The relationship between salivary Fibroblast Growth Factor-2 and cortisol reactivity and psychological outcomes prior to and during the COVID-19 pandemic

J Affect Disord Rep. 2023 Jul:13:100606. doi: 10.1016/j.jadr.2023.100606. Epub 2023 Jun 7.

Abstract

Background: Fibroblast growth factor-2 (FGF2) is a biomarker that is associated with depression, anxiety and stress in rodents. In humans, we have previously demonstrated that salivary FGF2 increased following stress in a similar pattern to cortisol, and FGF2 (but not cortisol) reactivity predicted repetitive negative thinking, a transdiagnostic risk factor for mental illness. The current study assessed the relationship between FGF2, cortisol, and mental health before and during the COVID-19 pandemic.

Methods: We employed a longitudinal correlational design using a convenience sample. We assessed whether FGF2 and cortisol reactivity following the Trier Social Stress Task (TSST) were associated with DASS-21 depression, anxiety and stress, measured at the time of the TSST in 2019-20 (n = 87; time 1), and then again in May 2020 during the first wave of COVID-19 in Sydney (n = 34 of the original sample; time 2).

Results: FGF2 reactivity (but not absolute FGF2 levels) at time 1 predicted depression, anxiety, and stress across timepoints. Cortisol reactivity at time 1 was associated with stress over timepoints, and absolute cortisol levels were associated with depression across timepoints.

Limitations: The sample was comprised of mostly healthy participants from a student population, and there was high attrition between timepoints. The outcomes need to be replicated in larger, more diverse, samples.

Conclusions: FGF2 and cortisol may be uniquely predictive of mental health outcomes in healthy samples, potentially allowing for early identification of at-risk individuals.

Keywords: COVID-19; Cortisol; Fibroblast growth factor-2; Mental health; Salivary biomarker; Stress.