Hexadecanal as an Addon to Cognitive Processing Therapy for PTSD

This study is testing whether exposure to a naturally occurring odor molecule called hexadecanal — which humans produce themselves — can boost the effectiveness of a trauma-focused therapy called Cognitive Processing Therapy (CPT) for people with PTSD. **You may be eligible if...** - You are 18 or older with a diagnosis of PTSD according to standard criteria - You are eligible to receive CPT therapy at the National Center for Traumatic Stress and Resilience - You do not have any known allergies to the scent compound **You may NOT be eligible if...** - You have bipolar disorder, psychosis, or a neurological condition - You have an active drug addiction - You are currently receiving another form of psychotherapy - You were born without the ability to smell (congenital anosmia) Talk to your doctor to see if this trial is right for you.