Suicide is a staggering, tragic, and growing cause of death in the United States. One out of every 62 Americans will die from suicide, based on the national lifetime prevalence rate.1 More than 42,000 Americans died from suicide in 2014, making suicide the second leading cause of death in individuals age 15 to 34, the fourth leading cause among those age 35 to 54, and the tenth leading cause of death in the country overall.2 The incidence of suicide in the general population of the United States increased by 24% between 1999 and 2014.3 This tragedy obviously is not solving itself.
The proposal
U.S. Centers for Disease Control and Prevention (CDC) publishes statistics about the number of suicides, as well as demographic information, collected from coroners and medical examiners across the country. However, these sources do not provide a biological sample that could be used to gather data concerning DNA, RNA, and other potential blood markers, including those reflecting inflammatory and epigenetic processes. However, such biological samples are commonly collected by the U.S. medicolegal death investigation system. In 2003, this system investigated 450,000 unnatural and/or unexplained deaths (ie, approximately 20% of the 2.4 million deaths in the United States that year).4
Each unnatural or unexplained death is examined, often extensively, by a coroner or medical examiner. This examination system costs more than $600 million annually. Yet the data that are collected are handled on a case-by-case and often county-by-county basis, rather than in aggregate. The essence of the proposal presented here is to take the information and biological samples collected in this process and put them into a National Suicide Database (NSD), which then can serve as a resource for scientists to increase our understanding of the genetic, epigenetic, and other factors underlying death due to suicide. This increased understanding will result in the development more effective tools to detect to those at risk for suicide (ie, risk factor tests), to monitor treatment, and to develop new treatments based on a better understanding of the underlying pathophysiology and pathogenesis of suicide. These tools will reduce:
- the number of lives lost to suicide
- the pain and suffering of loved ones
- lost productivity to society, especially when one considers that suicide disproportionately affects individuals during the most productive period of their lives (ie, age 15 to 54).
The NSD will be organized as a government–private partnership, with the government represented by the National Institutes of Health (NIH) and/or the CDC. The goal will be to take the information that is currently being collected by the nation’s medicolegal death investigation system, including the biological samples, systematize it, enter it into a common database, and make it available to qualified researchers across the country. The administrative arm of the system will be responsible for ensuring systematic data collection, storage in a searchable and integrated database housed within the NIH and/or the CDC, and vetting researchers who will have access to the data, including those with expertise in genomics, molecular biology, suicide, epidemiology, and data-mining. (Currently, the CDC’s National Violent Death Reporting System, which is a state-based surveillance system, pools data on violent deaths from multiple sources into a usable, anonymous database. These sources include state and local medical examiners, coroners, law enforcement, crime labs, and vital statistics records, but they do not include any biological material even though it is collected [personal correspondence with the CDC, July 2016].)
Because information on suicides currently are handled primarily on a county-by-county basis, data concerning these deaths are not facilitating a better understanding of the causes and strategies for preventing suicide. Correcting this situation is the goal of this proposal, as modeled by the National Cancer Institute’s War on Cancer, which has transformed the treatment and the outcomes of cancer. If this proposal is enacted, the same type of transformation will occur and result in a reduction in the suicide rate and better outcomes for the psychiatric illnesses that underlie most instances of suicide.
The proposed NSD will address a major and common problem for researchers in this area—small sample sizes. When considered from the perspective of the size of samples feasible for most independent research teams to collect and study, suicide on an annual basis is rare—however, that is not the case when the incidence of suicide in the nation as a whole is considered. In contrast to the data concerning suicides that individual research teams can collect, the proposed genomic database will grow by approximately 40,000 individuals every year, until a meaningful reduction in deaths due to suicide is achieved.
From a research perspective, suicide, although tragic, is one of the few binary outcomes in psychiatry—that is, life or death. Although there may be >1 genetic and/or epigenetic contributor to suicide, within a relatively short period of time, the proposed database will amass—and continue to amass on an ongoing basis—data from a large population of suicide victims. Researchers then can compare the findings from this database with the normative human genome, looking for variants that are over-represented in the population of those who have died by suicide.
Environmental factors undoubtedly also contribute to the risk of suicide, given that the incidence of suicide increases with age, particularly among white males, and with the addition of psychiatric and medical comorbidities. Inflammatory processes also have been implicated in the pathophysiology of a number of psychiatric disorders, including major depression, which is the primary psychiatric risk factor for suicide. Therefore, consideration should be given to collecting whole blood samples if the time between death and autopsy is within an appropriate limit to obtain interpretable data concerning RNA (ie, gene expression) and even biomarkers of inflammatory and other processes at the time of the suicide. This approach has been used by Niculescu et al5,6 for whole blood gene expression. The rationale for using samples of whole blood is that this strategy could be more easily adapted to clinical practice in contrast to using samples from the target organ (ie, brain) or cerebrospinal fluid.