Urban living and bipolar disorder: a review of the recent evidence

Recent evidence has expanded understanding of how urbanization influences bipolar disorder, yet findings remain inconsistent due in part to heterogeneous definitions of urbanicity. This review synthesizes recent studies using a structured framework encompassing interconnected constructs, timing of exposure, and community-level mechanisms. The aim is to clarify potential mediating factors underlying the relationship between urban environments and bipolar disorder.

Few recent studies focus specifically on bipolar disorder, but most report a positive association between urbanicity and bipolar disorder risk or clinical encounters. Conventional urbanicity measures show limited associations with bipolar disorder related outcomes. In contrast, timing effects such as the interaction between urban birth and longest rural residence appear relevant. Community-level mechanisms constitute the most active domain of new research. Air pollution, high ambient temperatures, limited greenspace, and high walkability are associated with increased bipolar disorder risk or service use, while virtual exposure to nature appears beneficial.

Environmental and community-level characteristics may play a more significant role in bipolar disorder than traditional geographic definitions of urbanicity. However, findings remain fragmented due to variable operationalization, small study numbers, and limited replication. Future work requires clearer differentiation between urbanization constructs, adoption of standardized or context-specific measures, investigation of macro- and micro-environmental mechanisms, and comparative analyses across bipolar disorder subtypes and related disorders.