BD overall is associated with excess mortality from both natural and unnatural causes. Meta-analytic evidence suggests that all-cause mortality is approximately doubled, with particularly high relative risks for suicide (12-fold) and other unnatural causes (7-fold) alongside a substantial increase in natural-cause deaths (2-fold).⁹ However, most mortality studies have not separated BD-II from BD-I, leaving BD-II’s specific mortality profile uncertain. Limited data indicate substantial premature mortality in BD-II, for example, an estimated 10- to 20-year reduction in life expectancy,¹ with cardiovascular disease a major contributor to natural-cause deaths.^10,11 This is likely predicated by shared risk factors and operative biological pathways as well as adverse effects of prescribed agents.¹² Unnatural causes, especially suicide, also appear elevated. A large Swedish registry¹³ reported more frequent suicide attempts in BD-II than BD-I, yet meta-analytic work¹⁴ suggests that the risk of suicide death is broadly similar across the 2 subtypes. Many BD-II–focused studies have been underpowered or have not analyzed BD-II separately,^11,15–17 rendering conclusions tentative. Whether BD-II differs from BD-I in all-cause or cause-specific mortality remains largely unresolved because direct comparisons are scarce.¹⁸

Conclusions and Relevance  In this cohort study, BD-II was associated with a significant risk of premature mortality across multiple causes; even after accounting for shared familial factors and relative to BD-I, all-cause mortality remained elevated. These findings underscore the importance of comprehensive psychiatric care for individuals with BD-II.

All-Cause and Cause-Specific Mortality in Patients With Bipolar II Disorder – https://jamanetwork.com/journals/jamanetworkopen/fullarticle/2847398