Bipolar II Disorder Linked to Increased Premature Mortality: JAMA
Taiwan: Researchers have found in a new study that bipolar disorder, particularly bipolar II, is associated with accelerated biological aging and a higher risk of premature mortality from both natural and unnatural causes. These findings highlight the importance of integrated psychiatric and medical care to improve outcomes.
A large population-based study published in JAMA Network Open provides robust evidence linking bipolar II disorder (BD-II) to significantly increased long-term mortality. While bipolar disorders are known to impact overall health, most prior research has not clearly distinguished between bipolar I and bipolar II. This study specifically focused on BD-II, offering more precise insights into its long-term risks.
The research, led by Chih-Wei Hsu and colleagues, analyzed data from Taiwan’s National Health Insurance Database spanning over two decades. The study included 11,427 individuals diagnosed with BD-II and compared them with more than 45,000 matched controls without the disorder. Participants were followed for an average of 7.3 years to assess mortality outcomes.
The study revealed the following findings:
- Individuals with bipolar II disorder had a significantly higher risk of all-cause mortality compared to those without the condition.
- Over the follow-up period, more than 1,000 patients with BD-II died, with an approximately 62% higher risk of death than controls.
- Increased mortality was observed for both natural and unnatural causes.
- Natural-cause deaths included cardiovascular, respiratory, digestive, metabolic, and mental health–related conditions.
- Unnatural-cause mortality was markedly elevated, with over a fourfold increase, mainly due to suicide, unintentional injuries, and violence.
- The elevated mortality risk was consistent across age groups, sexes, and in individuals with coexisting psychiatric conditions.
- Within-family comparisons also showed higher mortality in BD-II, indicating that the association is not solely due to shared genetic or environmental factors.
- Compared with bipolar I disorder, BD-II was associated with higher overall mortality and greater natural-cause mortality.
- The risk of death from unnatural causes was similar between BD-II and bipolar I disorder.
- These findings highlight that BD-II carries a substantial health burden and is not necessarily a milder form of bipolar disorder.
The authors acknowledged certain limitations, including the lack of detailed clinical data such as symptom severity, lifestyle factors, and treatment adherence, which could influence mortality. Additionally, the study population was based in Taiwan, which may limit generalizability to other regions with different healthcare systems and lifestyles.
Overall, the study highlights the urgent need for comprehensive care strategies for individuals with BD-II. Strengthening early diagnosis, integrating physical and mental health care, and prioritizing suicide prevention could play a crucial role in reducing the excess mortality associated with this condition.
Reference:
Hsu C, Chen YB, Lai EC, et al. All-Cause and Cause-Specific Mortality in Patients With Bipolar II Disorder. JAMA Netw Open. 2026;9(4):e265535. doi:10.1001/jamanetworkopen.2026.5535
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