Background. ‘Forward psychiatry’ was introduced by the French Army in 1915 to stem the loss of troops to base hospitals. Also known by the acronym PIE (proximity to the battle, immediacy of treatment and expectancy of recovery, including return to duty), it was subsequently used by the British and Americans in both World Wars. The US Army used PIE techniques in Korea and Vietnam. Although widely accepted as an effective intervention, forward psychiatry is not amenable to random-controlled trials and only one controlled outcome study has been conducted.

Method. All 3580 soldiers with shell shock admitted to 4 Stationary Hospital between January and November 1917 were recorded. Unit details, military experience, length of stay and outcomes were analysed. Soldiers were categorized into combat, combat-support and non-combatant groups. Admissions were correlated with military operations to compare the impact of defensive and offensive phases of warfare.

Results. Rates of admission for shell shock rose significantly during offensives when physical casualties escalated. Combat troops were disproportionately represented. Over 50% of admissions had less than 9 months service in France and 21% broke down within 3 months of going overseas. Less than 20% returned directly to combat units, most going to other hospitals, convalescent depots or base duties.

Conclusions. Forward psychiatry was not effective in returning combat troops to fighting units but, by allocating soldiers to support roles, it prevented discharge from the armed forces. Uncertainties remain about relapses, including other routes that servicemen used to escape from a combat zone.