The mass expulsion and exile of Bhutanese de facto refugees to displaced camps in Nepal represents one of the world's most neglected humanitarian crises. We aimed to summarize the impact of the long-term displacement on refugee mental illness using systematic review techniques, a methodology seldom used in the humanitarian field. In order to examine the impact among the population and the association between tortured refugees over non-tortured refugees, we searched 11 electronic databases from inception to 12 May 2006. We additionally contacted researchers at the United Nations High Commission for Refugees (UNHCR) and at the Centre for Victims of Torture, Kathmandu, and searched the websites of Amnesty International, Human Rights Watch, Relief-Web, and the US State Department. We included any studies that use a pre-defined protocol to determine mental illness within this population. Six studies met our inclusion criteria. All were conducted amongst the Bhutanese populations residing in Nepalese refugee ca...