Clearance of fear memory from the hippocampus through neurogenesis by omega-3 fatty acids: a novel preventive strategy for posttraumatic stress disorder?

Posttraumatic stress disorder (PTSD) is a serious public health problem. Approximately 6.8% of persons in the United States develop PTSD at some time in their lives [1]. PTSD most often develops from traumatic events such as rape, assault and combat, and results far less frequently from experiencing natural disasters and accidents [2]. However, accidental injury is a frequent event and represents a considerable public health burden worldwide. According to the Global Burden of Disease Study, the top three contributors to worldwide burden of disease in the year 2020 are expected to be ischemic heart disease, major depression and motor vehicle accidents (MVAs) [3]. From the Japanese perspective, in 2008 approximately one million individuals were severely injured in MVAs, and recent advances in critical care medicine have increased the number of seriously injured patients who are able to survive their injuries [4]. Over the past decade, increasing attention has been devoted to psychiatric morbidity after accidental injury [5-12] as well as other critical illness requiring treatment in the intensive care unit (ICU) [13]. Indeed, important roles for mental health professionals in general hospitals are the early identification of injured patients who are at risk for developing PTSD and the prevention of the disorder.It is difficult to eliminate traumatic antecedents altogether, but preventive intervention for PTSD does seem possible. Secondary prevention involves intervening in the aftermath of a traumatic event to forestall the development of PTSD [14]. At the present time, the most well-known and evidence-based secondary preventive intervention for PTSD is cognitive behavioral therapy (CBT). A study by Roberts and colleagues [15] found that trauma-focused CBT within 3 months of a traumatic event appeared to be effective for individuals with traumatic stress symptoms, especially those who met the threshold for a clinical diagnosis. Furthermore, a brochure on bereavement d