Two workshops were convened for the committee on the Pathophysiology and Prevention of Adult and Adolescent Suicide of the Institute of Medicine. Workshop I was on Risk Factors for Suicide and convened on March 14, 2001. Workshop II was on Suicide Prevention and Intervention and convened on May 14, 2001. The two workshops were designed to allow invited presenters to share with the committee and other workshop participants their particular expertise in suicide, and to discuss and examine the existing knowledge base.
The two workshops are part of the information-gathering activities that inform the work of the committee. It is the committee’s task to assess the science base of suicide etiology, evaluate the current status of suicide prevention, and examine current strategies for the study of suicide. Its full report, which will include consensus statements on the scientific literature of the causes of and risk factors for suicide, and will illuminate contentious issues and gaps in the knowledge base, should guide prevention efforts and intervention. This is the summary for Workshop II, Suicide Prevention and Intervention.
Participants for Workshop II, Suicide Prevention and Intervention, were selected to represent the following areas: design and analysis of prevention programs, systems interventions for youth, suicide contagion, cognitive approaches to suicide, prevention across psychiatric diagnoses, prevention opportunities in general medical practice, and firearm availability and suicide. Among the different topic areas, the committee hoped to find current knowledge on effectiveness of current prevention and intervention methods and best areas of opportunity for suicide and attempted suicide. Participants were asked to present current and relevant knowledge in each of their expertise areas—knowledge both empirically-derived as well as commonly known from professional experience. The agenda for the workshop is in Appendix A.
This workshop was not intended to be a formal or comprehensive review or analysis of the scientific literature on risk factors for suicide or attempts. No conclusions or recommendations were made from this activity.
This report will summarize major themes that emerged over the course of the one-day workshop. Quotations are provided from the workshop discussions.
Although the workshop participants present from a number of diverse perspectives, all share a fundamental belief in the potential for better suicide prevention.
DESIGN CHOICES AND ANALYTICAL STRATEGIES FOR POPULATION-BASED PROGRAMS: IMPLICATIONS FOR SUICIDE PREVENTION
Dr. C.Hendricks Brown discussed a framework and strategies for suicide prevention research. He discussed how to evaluate programs, and described an early intervention program for violence as a model for suicide prevention. He underscored three challenges facing suicide prevention. (1) Suicide is a low base-rate behavior, approximately 12 per 100,000 in the population at large. Therefore, changes in numbers of suicides must be studied appropriately to ensure that any change is due to the intervention, and not to other factors. (2) Risk factors for suicide are non-specific, since they associated with other undesirable outcomes. Therefore study of simple
causal relationships for suicide is not possible. (3) Risk factors can change in individuals over short periods of time, and across developmental life-stages, further complicating assessment of suicide risk and prevention.
Prevention Framework. Dr. Brown described three levels of the currently most broadly used conceptualization of prevention. (1) Universal interventions are delivered to everyone, regardless of an individual’s vulnerability. The law requiring seat belt use is an example. (2) Selected interventions are delivered to groups at increased risk. Anti-alcohol abuse classes for adolescents is an example. (3) Indicated prevention is given to individuals who have a known risk factor. For suicide prevention, treating a person with depression is an indicated prevention.
If you are doing a selective or indicated intervention, the only impact you are going to have is on those people who you have identified. You have no impact on those who are at risk, but you missed.
According to Dr. Brown the best prevention programs combine interventions on more than one level. Such “unified intervention” strategies are more effective and more practical. They avoid problems faced when individuals’ risk factors change over time. Programs using only one level of intervention have to exclude individuals whose level of risk changes during the program, possibly putting these people at risk if exclusion from the program means they lost their only available treatment. In addition, information about the common occurrence of changing risk levels is lost, hindering evaluation of the program.
Prevention Program Strategies. Dr. Brown listed four general strategies for prevention. They are: developmental approaches, individual approaches (reducing risks and increasing protective factors), intervention through policy and law, and intervention through the social context (e.g., reducing poverty, child abuse). Dr. Brown described a promising new strategy of the last type, called “The Empowerment Intervention.” In this design, two communities are randomly assigned to either starting a prevention program immediately, or waiting 1 year before starting. Five community pairs make up the data set. This allows collection of “good quantitative data that is not confounded with community readiness and other community characteristics,” according to Dr. Brown.
Dr. Brown noted that it is important to take into account two proportions when trying to estimate the number of people targeted by a particular prevention effort. The first is “population-attributable risk.” This is the proportionate reduction in number of cases of the condition that would occur upon elimination of a particular risk factor from the population at large. For example, one risk factor associated with the vast majority of completed suicides is depression, according to Dr. Brown. Therefore, if depression could be eradicated from the general population, the vast majority of suicides, according to Dr. Brown’s explanation, would be prevented. The second proportion to consider when designing prevention efforts is the “relative risk.” The rela-
tive risk is the proportion of the population with a particular risk factor (e.g., depression) who get the condition (suicide), divided by the proportion of unexposed (those without depression) who commit suicide. By taking into account the population-attributable risk, the relative risk and the number of people in the target population, one can estimate the number of suicides one is aiming to prevent, according to Dr. Brown.
In general, the more refined your definition of relative risk, the smaller the proportion of people within the population with those risk factors.
Program Evaluation. Dr. Brown reported that the suicide prevention field is significantly behind in quality of study measures, impacting our ability to evaluate results across studies. The workshop attendees discussed approaches to dealing with these problems. The following observations were made. (1) Since suicide is a low base-rate behavior, it can be difficult to tell whether the rate is lowered any further by the prevention program beyond normal fluctuations. Studying large samples can address this problem. Studying prevention in groups at higher risk is another way to approach the problem of studying prevention of a low-base rate behavior. (2) Subjects need to be assigned to different treatment groups randomly, so that the outcome is not biased by the incoming characteristics of the people in a given group. (3) The interventions need to be described in adequate detail for replication and further study. (4) Risk factors must be assessed throughout the study to verify individual levels of risk, and to monitor for change over time. (5) Effects of developmental life-stage can be examined by testing for interactions between risk factors and interventions.
Early risk factors can be modified well before most of the suicidal attempts occur.
The workshop attendees discussed the significant drop-off in suicide rate during the first few years after intervention and treatment, an observation made across many studies. Drs. Mann and Fawcett described recent research where most of the suicides occurred within the first year after the intervention, with a precipitous drop off during the subsequent 2 to 3 years. Dr. Brown described a recent review of the world literature on long-term patient survival and found that the older the study, the higher the long-term mortality due to suicide, as compared to more recent studies. Drs. Mann, Pearson, and Tsuang discussed that future research needs to study other possible mitigating factors such as changes in population rates and severity of illness and the incidence of hospitalization before the meaning of these observations can be known.