NPS and post-traumatic stress disorder: We synthesise the state of this evidence in this mini review focusing on the evidence for sex differences in (1) genetic and epigenetic factors; (2) other biological factors including (i) brain structure and function, (ii) immunological, neuroendocrine, and neuropeptide responses, and (iii) the role of sleep; (3) rates of recovery and response to treatment; and (4) medical and psychiatric comorbidities, in PTSD.