This dissertation explores the links between contemporary First World War poetry, modern fiction on the Great War and psychology in their historical context. At the time of the Great War, psychological ailments known under the header ‘neurasthenia’ or ‘shell shock’ were a relatively new phenomenon which puzzled society at the time. By comparing actual case files of renowned doctors and psychologists of the time—such as W.H. Rivers—with the works of selected War poets—such as Siegfried Sassoon, Wilfred Owen and C.H. Sorley—the extent of the pervasiveness of shell shock becomes apparent. Psychological issues such as muteness, repression, suppression and war dreams are amply referred to in First World War poetry, which demonstrates the level of exposure of the poets to these ailments, and its subsequent importance. In this dissertation it becomes clear that modern fiction draws on the same methods and themes as the works written at the time of the war. The Regeneration trilogy by Pat Barker is analyzed in the same way as the poetry, since she worked from a neurasthenic viewpoint and focused on a historicized reading of the works of the War poets. She employed similar techniques and psychological themes as the poets to engage her reader, and to accurately portray a World War I setting. However, it is clear that she is a modern author, and deviates from ideas from the time at certain points.