Low blood pressure may increase the risk for suicidal ideation, new research shows.
Among more than 10,000 South Korean adults, those with systolic blood pressure (SBP) <100 mm Hg were at higher risk of having suicidal thoughts compared to their peers with normal blood pressure.
“Although previous studies suggested that low blood pressure is associated with neuropsychological problems, including depression and anxiety, no studies have investigated the association between low blood pressure and suicidal ideation, which is an indicator of a negative psychiatric state,” Sung-il Cho, MD, from Seoul National University, said in a statement.
“Our findings suggest that the health implications of low blood pressure may need to be evaluated to take into account potential adverse effects on mental health,” added Cho.
The study was published online in BMC Public Health.
The researchers analyzed data on 10,708 adults who participated in the 2010-2013 Korean National Health and Nutrition Examination Survey. Overall, 1199 (11.2%) had experienced suicidal ideation, identified by asking one of two questions: “Have you ever felt inclined to commit suicide over the last year?” (2010-2012) and “Have you ever considered suicide seriously over the last year?” (2013).
Suicidal ideation was more common in women than men (12.9% vs 7.8%) and in those aged 70 years and older (20.8%).
The researchers used four cut-off values to define low blood pressure: SBP <110 mm Hg, <100 mm Hg, <95 mm Hg, and <90 mm Hg. Altogether, 2569 (24%) adults had low blood pressure, and 8139 (76%) had normal blood pressure.
According to the investigators, 10.8% of people with normal blood pressure had experienced suicidal ideation. For people with low SBP, this proportion increased to 12.5% in those with SBP <100 mm Hg, 13.7% in those with SBP <95 mm Hg, and 16.6% in those with SBP <90 mm Hg.
Compared with the normotensive reference group, the likelihood for suicidal ideation was significantly higher in those hypotensive groups with SBP <100 mm Hg, < 95 mm Hg, and < 90 mm Hg after adjusting for sex, age, body mass index, total cholesterol level, household income, educational level, marital status, current smoking status, alcohol intake, and the interaction between sex and age.
Further adjustment for diabetes, stroke, myocardial infarction/angina pectoris, and depression as covariates had little effect on the strength of these associations, the researchers say. No significant association was found between prehypertension or hypertension and suicidal ideation.
“Although prehypertension may be a risk factor for cardiovascular diseases and should be managed, it does not appear to have a negative impact on mental health. Low blood pressure may pose different health issues compared to high blood pressure, and our study challenges the perception that in terms of mental health, lower blood pressure is really always better,” said Cho.
The researchers caution that this is a cross-sectional study and cannot prove a causal relationship between low blood pressure and suicidal ideation. Also, the use of self-reported survey data may have introduced information and recall bias. In addition, because only levels of SBP were used to define low blood pressure, future studies are needed to explore the relationship between suicidal ideation and diastolic blood pressure.
Despite these limitations and caveats, the researchers note that the findings are in line with several earlier studies suggesting a correlation between low blood pressure and psychological symptoms, such as depression and anxiety.
Taken together, the results support the “BP-emotional dampening hypothesis,” which suggests that BP has an inhibitory effect on overall negative emotional experience and pain perception, they wrote – acknowledging that further research was needed..
REFERENCE: Kyung-in Joung and Sung-il Cho; Association of low blood pressure with suicidal ideation: a cross-sectional study of 10,708 adults with normal or low blood pressure in Korea; https://bmcpublichealth.biomedcentral.com/articles/10.1186/s12889-018-5106-5