Low blood pressure may be associated with suicidal thoughts, also known as suicidal ideation, according to a study involving 10,708 Korean adults aged 19-101 years with normal or low blood pressure, published in the open access journal BMC Public Health.
Researchers at Seoul National University, South Korea found that participants with systolic blood pressure of lower than 100 mmHG had higher odds of suicidal ideation compared to participants with normal blood pressure. mmHG refers to millimeters of Mercury, a common measure for blood pressure.
Professor Sung-il Cho, the corresponding author said: “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. 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.”
The authors found that out of a total 10,708 participants, whose data were used to examine the association between blood pressure and suicidal ideation in a general population, 2,569 (24%) had low blood pressure (lower than 100 mmHG) and 1,199 participants (11.2%) had suicidal ideation. Suicidal ideation was found to be more common in women than men (12.9% of women vs. 7.8% of men) and highest in the oldest age group (20.8% in people aged 70 or over).
Investigating different levels of low blood pressure, the authors found that the proportion of participants with suicidal ideation was higher in groups with lower blood pressure; out of 2,569 participants with systolic blood pressure of lower than 100 mmHG, 320 (12.5%) had suicidal ideation, out of 1,073 participants with systolic blood pressure of lower than 95 mmHG 149 (13.7%) had suicidal ideation and out of 319 participants with systolic blood pressure of lower than 90 mmHG 53 (16.6%) had suicidal ideation, compared to 879 (10.8%) out of 8129 participants with normal blood pressure.
The higher tendency in the groups with low blood pressure to have suicidal ideation suggests that there may be an association between the two, according to the authors. No significant association was found between prehypertension or hypertension and suicidal ideation.
Sung-il Cho said: “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. So 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.”
The authors used data from 2010-2013 from the Korean National Health and Nutrition Examination Survey, a nationwide, large-scale survey aimed at understanding the health and nutritional state of the Korean population. Data collected as part of the survey include a household and health interview, a health behavior survey, and a medical examination. Suicidal ideation was 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).
The authors caution that the cross-sectional nature of the study does not allow for conclusions about cause and effect and that a two-way relationship between low blood pressure and suicidal ideation cannot be ruled out. The study’s use of self-reported survey data may have introduced information and recall bias. As only levels of systolic blood pressure were used to define low blood pressure, future studies are needed to explore the relationship between suicidal ideation and diastolic blood pressure. Further research is also needed into the possible biological mechanisms that may explain the association between blood pressure and suicidal ideation.