Chris never had shell shock?

I recently taught Rebecca West's WWI novel The Return of the Soldier (using the new Broadview contextual edition) in conjunction with Pat Barker's Regeneration--a terrific combination by the way. Interestingly, one of my graduate students claimed that Chris is not actually a victim of shell shock but is either shamming or simply mis-diagnosed by his doctors. She came to this conclusion after reading both Regeneration and W.H.R. Rivers's essay "The Repression of War Experience," seeing in Chris none of the symptoms of actual repressed war trauma as are described in these two other texts. Such a revisionist reading would open new, intriguing ways of approaching the novel, notably suggesting that Chris is suffering from a condition that is not directly related to the Great War. Any comments are welcome.