Relationships between adverse childhood experiences, oxidative stress, and development of mental disorders: A systematic review of animal and human studies.

Adverse childhood experiences (ACE) are common risk factors for many psychiatric disorders. Their underlying biological mechanisms may involve oxidative stress (OS), which has deleterious effects on cells through its own actions and through its interactions with inflammation and the stress axes, particularly in the brain. In order to assess the role of OS in the association between ACE and psychopathology, we performed a systematic review of animal and human research (PROSPERO CRD42023378418 and CRD42022378376), funded by the Swiss National Science Foundation (grant number 204033). PubMed, Web of Science, PsycInfo, Scopus and Embase were searched from inception until 31 October 2024. We included 130 studies involving animal models exposed to stressor-paradigms recognized as ACE analogs before they reached adulthood, or human participants with a history of ACE and assessment of psychopathology, and reporting outcomes on OS-related markers. Animal studies overall show increased OS and psychopathology after stress, thus supporting the hypothesis that OS mediates the relationship between ACE and psychopathology. Human studies are heterogeneous and less conclusive. Although the association between ACE exposure and OS, in animals and humans, was likely affected by the nature, the timing, and the intensity of the exposure, these parameters were only evaluated in a small fraction of studies. Similarly, though some studies hinted at sex differences in the OS response to ACE in animals, the majority of studies did not address this issue. Further research, using longitudinal designs and more thorough examination of ACE history in participants, is therefore needed.