The Efficacy of a Single Dose of Intranasal Oxytocin in the Prevention of Post Traumatic Stress Disorder (PTSD)

Inclusion Criteria: 1. Persons over the age of 18, who have been exposed to an event meeting the DSM-IV "A.1" criterion for trauma exposure, expressing marked anxiety, and/ or emotional distress and/or dissociation, as assessed by the Visual Analog Scales 2. The traumatic event occured up to six hour prior to the arrival to the emergency room 3. The person can and is willing to provide written, informed consent to participate in the study. Exclusion Criteria: 1. Physical injury that would contraindicate participation or interfere with a subject's ability to give informed consent or cooperate with the screening or collection of initial measures. Examples include severe burn injury, life-threatening medical or surgical condition, condition requiring surgical intervention under general anesthesia, as indicated by Abbreviated Injury Scale (AIS), or by clinical judgment; 2. Head injury involving confusion, loss of consciousness, or amnesia; 3. Medical conditions in which oxytocin administration might cause harm to the patient such as patients with a cardiovascular disease or intracranial mass. 4. Weight below 45 or above 100 kg. 5. Pregnancy (in suggestive cases, a pregnancy test will be performed); 6. Traumatic exposure that reflects ongoing victimization (e.g., domestic violence) to which the subject is likely to be re-exposed during the study period. 7. Overt psychopathology, intoxication, or under the influence of substances. 8. Evidence or history of schizophrenia, bipolar, other psychotic condition, autism; 9. Prior history of PTSD; 10. Current or past history of dementia, amnesia, or other cognitive disorder predating trauma exposure; 11. Assessed serious suicide risk.