Shell-shock is a term used to describe the psychological trauma experienced by soldiers during and after warfare. It is also known as combat stress reaction, battle fatigue, or post-traumatic stress disorder. The term 'shell-shock' was first used in World War I to describe the physical and psychological effects of the intense bombardment of artillery shells. The term 'STUN' is often used to describe the physical and psychological effects of shell-shock, which can include confusion, disorientation, anxiety, depression, and nightmares.