Final answer:
Shell shock, also known as battle fatigue or post-traumatic stress disorder (PTSD), was a common condition for soldiers in the trenches of World War I.
Step-by-step explanation:
The common condition for soldiers in the trenches of World War I was shell shock. Shell shock, also known as battle fatigue or post-traumatic stress disorder (PTSD), was caused by the intense psychological pressures of war rather than the actual shelling. Symptoms of shell shock included shaking hands, constant twitches, flashbacks to battle, inability to speak, loss of contact with reality, and fear of unexpected sounds. Treatment for shell shock was slow and focused on helping soldiers reenter peacetime society.