In addition to using the Danish Cause of Death Register to determine risk of suicide-related death, Dr. Lund-Sorenson and her team used incidence rate ratios and accompanying 95% Cis to measure relative risk, according to the study. The study’s results found that there was a 42% higher risk of suicide-related death in individuals who were hospitalized with an infection compared to those who were not infected. In addition, the researchers noted that two other factors were also linked to an elevated risk for suicide-related death: the number of infections and the length of the treatment. The more infections the individual had, and the longer they were on a treatment plan, the higher their risk was for suicide-related death.
Drs. Brundin and Grit wrote, “Strengthening the case for a possible causal role of infections in the pathogenic process that leads to suicide, these researchers show that an increased risk of suicide was associated with the length of treatment and with an increasing number of hospitalizations with infections. Individuals with seven or more infections had an increased risk of suicide of almost 300 percent.”
Individuals with the highest risk of suicide were those infected with hepatitis or HIV/AIDs, “which is in line with previous findings that these patients report higher levels of suicidal ideation and behavior than the general population,” according to the study, "[and] HIV or AIDS infection is strongly linked with psychiatric disorders (eg, depression and substance use).” Using a sensitivity analysis, the researchers found that compared to individuals who were diagnosed with a psychiatric disorder but did not have an infection, individuals who had been diagnosed with an infection before any kind of psychiatric disorder showed an increased risk of suicide-related death. However, the researchers do admit that the suicidal risk of a hospitalized patient with severe infection could be influenced by psychological factors.
The researchers were not able to determine if depression and other risk factors for suicide-related deaths could be associated with the individual’s self-care, and thus, could be linked to severity of infection. In addition, they noted that another limitation to their study was that they were unable to determine if disability due to severe infection or hospital treatment itself could explain risks for suicide-related deaths, according to the news release.
In their study, the researchers concluded, “Our findings indicate that infections may have a relevant role in the pathophysiological mechanisms of suicidal behavior. Provided that the association between infection and the risk of death by suicide was causal, identification and early treatment of infections could be explored as a public health measure for prevention of suicide. Still, further efforts are need to clarify the exact mechanisms by which infection influences human behavior and risk of suicide.”
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