PTSD symptoms can include dissociation, fatigue, and 'checking out,' which are parasympathetic responses.

“in terms of autonomic arousal right things like dissociation fatigue um kind of checking out which I realize this dissociation but things that uh are more akin to kind of parasympathetic right for those that don't know the sympathetic parasympathetic represents the Continuum of autonomic interaction sympathetic having nothing to do with emotional sympathy it's all about um fight ORF flight type responses although at lower levels it's what's responsible for us being alert here but not in fight ORF flight and parasympathetic being more of the rest and digest even leading into sleep type responses”