5.4.2. Post-Traumatic Stress Disorder

The fear response associated with a trauma-related stimulus may be targeted by ketamine. In addition, rodent models have demonstrated ketamine's ability to promote fear extinction, which is suggested to occur via mTORC1 signalling [88]. Thus, it may be appropriate as an adjunct to extinction therapies, whereby a fear-associated cue is exposed to patients with the aim to form a new memory associated with it via inhibitory learning [89]. In this way, ketamine treatment may be especially efficacious for PTSD when "harnessing a window of ketamine-induced neuroplasticity" [90].

Early studies of ketamine for PTSD in humans administered the drug immediately after exposure to trauma, which produced mixed findings [91]. Later studies have investigated its use to treat chronic PTSD, and whilst, to date, there are few randomisedcontrolled trials (RCTs), the results are promising. For example, in one double-blinded RCT of 41 chronic PTSD patients, the PTSD symptoms and depression improved in response to ketamine as opposed to midazolam [15]. Another study found increases in the length of the clinical response to a mindfulness-based extinction and reconsolidation cognitive therapy in patients given IV ketamine relative to a saline placebo [92]. Overall, these preliminary findings were promising, and ketamine is likely a viable treatment option for patients who have experienced trauma.
