CHRNA7 and post-traumatic stress disorder: Cotinine, an active metabolite of nicotine has drawn significant attention in the recent past as a potential positive modulator of α7 nicotinic acetylcholine receptor (α7nAChR), and in a mice PTSD model, it actively enhances the fear extinction and reduces anxiety and depressive behaviour in an α7nAChR-dependent manner (Barreto et al. 2015; Mendoza et al. 2018; Aliev et al. 2020).