Introduction
Neuroprogression has been proposed as the pathological rewiring of the brain that takes place in parallel with clinical and neurocognitive deterioration in the course of psychiatric disorders. This study aims to review the biological underpinnings and clinical outcomes related to neuroprogression in post-traumatic stress disorder (PTSD). 

Methods
We performed a systematic review by searching PubMed, Embase, and Web of Science for articles published between January 1, 1960, and January 6, 2020. Inclusion criteria were met when articles assessed brain changes, neurocognition, functioning, inflammation, oxidative stress, and neurotrophins in patients with PTSD. Narrative review articles, case reports, and preclinical studies were excluded. 

Results
A total of 965 abstracts were identified and 15 articles were included in our systematic review. It seems that for a subset of patients whose symptoms worsen or are maintained at a high intensity there is a progressive change in the frontal lobe, especially the prefrontal cortex, and worsening of both neurocognition (verbal memory and facial recognition) and functioning (physical, psychological, social and environmental). 

Conclusion
Although current findings associate progressive reduction in frontal lobe size with neurocognitive impairment, further research is needed to characterize PTSD as a neuroprogressive disorder.