is entitled to service connection for PTSD . For the following reasons , the Board finds service connection is warranted . Service connection will be granted if the evidence demonstrates that a current disability resulted from an injury or disease incurred in or aggravated by active service . 38 U . S . C . A . § § 1110 , 1131 ; 38 C . F . R . § 3 . 303 ( a ) . Establishing service connection generally requires competent evidence of three things : ( 1 ) a current disability ; ( 2 ) in - service incurrence or aggravation of a disease or injury ; and ( 3 ) a causal relationship , i . e . , a nexus , between