The complexity of delayed diagnosis in bipolar disorder. A systematic review of associated precursors, outcomes, and suggested avenues for improvement.

There are widespread stakeholder concerns about adverse consequences of persistent long delays in diagnosing and treating bipolar disorder. Average five-to-ten-year delays are substantiated by previous evidence synthesis, which has focused primarily on quantifying scale. Nevertheless, we lack a complex and broad understanding of diagnostic delay. This review incorporates a complex intervention framework, using co-produced narrative synthesis of quantitative and qualitative studies to identify associated precursors, outcomes, and suggested avenues for improvement. We searched four databases and included 49 generally high-quality studies from high or middle-income countries. This review reinforces some findings from previous reviews regarding scale of delayed diagnosis and key associated precursors, including: history of depression, suicide attempts, earlier onset, female sex, BD-II presentation. However, we also identify a wider range of associated factors and proposed strategies for improvement, which lead us to conclude that future research and interventions should examine delayed diagnosis in terms of its breadth and complex interrelationships with other aspects of bipolar disorder which remain insufficiently understood. These include: mixed, hypomanic, atypical, and rapid cycling presentations; suicidality in bipolar and its interrelationship with diagnosis, acknowledging the persistence of suicide risk following diagnosis; interrelationship with diverse mental and physical health conditions; attitudes and management of bipolar; the diagnostic process in lower-and-middle income countries; clinical pathways associated with diagnosis and the complex interplay of socio-economic, cultural, and demographic factors and diagnosis. Our review also highlights the need for deeper insight into stakeholder experiences and attitudes toward bipolar management and diagnosis, particularly through qualitative, mixed-methods, and co-produced research.