In Regeneration, mutism functions as a symbolic manifestation of the disempowerment and helplessness the men feel. Both Prior and Callan are affected by mutism after extremely horrifying incidents. Rivers reasons that mutism might be caused by an inability to voice dissent or express opinion over any part of one's own life. He notes that mutism occurs most often among regular soldiers, not officers—men who are entirely at the mercy of their commanders. Mutism, however, is in itself an assertion of power. Through silence, these men are disobeying those who have power over them. How Rivers and Yealland differently handle mutism is a reflection on their own need to reinforce control over their patients.
Trenches are symbolic in the novel, much as they are in the poetry of the Great War. The trenches are likened, both literally and figuratively, to graves. Many of the patients have terrible experiences and memories involving trenches. Prior, most notably, remembers waking up in a trench one morning, only to turn around and find two of his men killed by an exploded shell. The trench became the men's grave, as Prior was forced to mix their remains with lyme and use them to reinforce the walls of the trench.