Background. The current study provides the first epidemiological estimates of lifetime mental disorders across NI based on DSM-IV criteria. Risk factors, delays in treatment and the experience of conflict are also examined.Method. Nationally representative face-to-face household survey of 4340 individuals aged o18 years in NI using the Composite International Diagnostic Interview. Analyses were implemented using SAS and STATA software.Results. Lifetime prevalence of any disorder was 39.1% while projected lifetime risk was 48.6%. Individuals who experienced conflict were more likely to have had an anxiety, mood or impulse-control disorder. Treatment delays were substantial for anxiety and substance disorders.Conclusions. Results from this study show that mental disorders are highly prevalent in Northern Ireland. The elevated rates of post-traumatic stress disorder in relation to other countries and the association of living ‘ in a region of terror ’ disorders suggests that civil conflict has had an additional impact on mental health. Given substantial delays in treatment, further research is required to investigate the factors associated with failure and delay in treatment seeking.