Problems sleeping are common after exposure to highly threatening experiences and can occur
with and without a diagnosis of posttraumatic stress disorder (PTSD). Established treatments
for PTSD are limited for addressing insomnia and many insomnia treatments appear to be
limited in the context of PTSD. Suvorexant is FDA approved for insomnia and among approved
drugs has a unique mechanism of action that may be well suited for targetting arousal at
night dysregulated by trauma. The investigators will evaluate the efficacy of suvorexant for
insomnia that developed in relation to trauma exposure, utilizing a placebo control, and
polysomnography to identify biomarkers of response, in a six week trial.