Early adversity affects cerebellar structure and function – A systematic review of human and animal studies

Recent research has highlighted cerebellar involvement in cognition and several psychiatric conditions such as mood and anxiety disorders, and schizophrenia. Attention deficit-hyperactivity disorder and autism spectrum disorder have been linked to reduced cerebellar volume as well. Notably, cerebellar alterations are frequently present after early adversity in humans and animals, but a systematic integration of results is lacking. To this end, a systematic literature search was conducted in the PubMed database using the keywords ‘early adversity OR early life stress’ AND ‘cerebellum OR cerebellar’. 33 publications met the inclusion criteria. Of these, 17 studies investigated human subjects and 16 reported results from animal models. Findings in healthy subjects show bilateral volume reduction and decreased functional connectivity within the cerebellum and between the cerebellum and frontal regions after adversity throughout life, especially when adversity was assessed with the Childhood Trauma Questionnaire. In clinical populations, adults demonstrate increased cerebellar volume and functional connectivity after adversity, while pediatric patients show reduced cerebellar volume. Animal findings reveal cerebellar alterations without cooccurring pathological behavior, highlighting alterations in stress hormone receptor levels, cell density, and neuroinflammation markers. Cerebellar alterations after early adversity are a robust finding across human and animal studies and occur independent of clinical symptoms.