of soundness is applied , if the Secretary is unable to rebut the presumption , the disease or injury that manifested in service is deemed incurred in service , such that the second element of service connection is established . At that point , however , a veteran still must establish that he has a current disability that is related to the in - service injury or disease . This nexus determination is based on a weighing of the evidence by the preponderance of the evidence standard , with the benefit of the doubt given to the veteran . It is error to apply the presumption of soundness without first addressing or finding whether the Veteran ' s psychiatric disability manifested in service . See Gilbert v .