to her in - service experiences is testimony as to an internal psychiatric process , unlike the immediately observable cause - and - effect relationship of the type as to which the courts have found lay evidence to be competent . Compare Clemons v . Shinseki , 23 Vet . App . 1 , 6 ( 2009 ) ( " It is generally the province of medical professionals to diagnose or label a mental condition , not the claimant " ) with Jandreau , 492 F . 3 d at 1376 ( lay witness capable of diagnosing dislocated shoulder ) ; Falzone v . Brown , 8 Vet . App . 398 , 403 ( 1995 ) ( lay person competent to testify to pain and visible flatness