Participants arriving to the ED following a potentially traumatic event such as a motor vehicle accident will be recruited into the study. Inclusion criteria: aged 18-65, Hebrew as a first language, no current psychiatric disorder. Exclusion criteria: loss of consciousness, unable to understand study procedure. Participants will answer self report questionnaires in the ED. They will be invited for a follow up interview 2 weeks and six months post trauma. Between 2 weeks and 6 months they will be folllowed up via online questionnaires. At the interviews, they will encounter 20 different olfactory stimuli, answer self-report questionnaires, and a clinical interview assessing Axis 1 disorders and PTSD will be completed. At six month, participants with PTSD will be offered therapy in the embedded RCT. Patients will receive VRET (Virtual reality exposure therapy) with or without olfaction.

The goal of this project is to carry out a systematic longitudinal study with an embedded RCT examining olfactory memories in PTSD, in order to test the following hypotheses. Firstly, olfactory memories occur after all traumatic events; secondly, olfactory memories are predictors of PTSD development and thirdly, adding olfaction to PTSD treatment will enhance treatment outcome. The project comprises of a longitudinal study recruiting participants in the Emergency Room within hours of a traumatic event, assessing them at two weeks post trauma for olfactory memories, and at six months for PTSD. This will allow the first two hypotheses to be examined. Participants with PTSD and olfactory memories will be offered treatment and will be randomized to a Virtual Reality Exposure Therapy with and without added odors. Post treatment assessments will examine the third hypothesis.

Inclusion Criteria:

• hebrew native speaker
• understand study requirements

Exclusion Criteria:

• current psychiatric disorder
• suicidality
• vertigo
• epilepsy