To improve the safety of healthcare systems, it is necessary to understand harm-related events that occur in these systems. In mental health services, particular attention is paid to harm arising from the actions of patients against themselves or others. The primary intention of examining these adverse events is to inform changes to care provision so as to reduce the likelihood of the recurrence of such events. The predominant approach to investigating adverse incidents has relied on the cause-and-effect conceptualisation of past events. Whilst the merits of approaches which are reliant on cause-and-effect narratives have been questioned, alternatives models to explain adverse incidents in health settings have not been theoretically or empirically tested. This novel article (i) examines the notion of causation (and the related notion of omission) in the context of explaining adverse events in mental health settings, and (ii) draws on a long-established discipline devoted to the study of how the past is interpreted (namely historiography) to theoretically investigate the innovative application of two historiographical approaches (i.e. counterfactual analysis and historical materialism) to understanding adverse events in mental health settings.