Suicidology Meeting Genetics

Abstract

In 2000, the so-called book of life (the human genome) was revealed. Six years later a range of genetic tests has been developed. The genetic code seems to influence almost everything from health through potential to develop disorders to disorders themselves – and the effects of drugs in these disorders. Inherited predisposition is an important component in a number of common diseases that contribute significantly to the health burden of our societies, e.g., atherosclerosis, hypertension, diabetes mellitus, cancer, mental disorders, and many others. Indeed, recent developments in molecular genomics and accompanying technologies have changed our understanding of both health and disease. Consequently, changes in our approaches to treatment and prevention have followed. For example, because it appears that genetic approaches are likely to become an important part of health care, it is necessary for health workers to improve their overall knowledge of health genetics. As a response, the World Health Organization (WHO) has launched the Human Genetics Programme as a separate program in the WHO dealing with genetic approaches to prevention and control of diseases. Their main priorities are not only genetic diseases and congenital disorders, but also common diseases with genetic predisposition (such as coronary heart disease or depression), the analysis of the relevant ethical, legal, and social issues, and education and training aimed at patients, families, and health professionals alike. Suicidal ideation and behavior are not considered disorders like depression. However, they do represent one of the biggest public health concerns in the contemporary world. Like many other complex traits, suicidal behavior too seems to cluster in families. Moreover, first-degree relatives of individuals who have committed suicide (including dizygotic twins) are more than twice as likely to die by suicide compared with the general population. In the case of identical twins, the concordance of suicide is even greater than is the case with fraternal twins (Roy, Segal, Centerwall, & Robinette, 1991). Genetic model fitting on one of the largest studies of twins showed more that 40% of the variability of suicidal behavior can be explained by genetics (McGuffin, Marusi2, & Farmer, 2001). The mode of inheritance of suicidal behavior is almost certain to be complex, involving many genes, and there have already been several studies and meta-analyses of allelic association with polymorphisms in candidate genes such as those involved in serotonergic transmission. Most recently, attention has also been paid to the possible interplay of these genes with environmental factors. In an interesting example of such simultaneously performed research, Caspi et al. (2003) tested why stressful experiences lead to depression in some people but not in others, using a prospective-longitudinal study of a representative birth cohort. The functional polymorphism in the promoter region of the serotonin transporter (5-HTT) gene was found to moderate the influence of stressful life events on depression, one of the main risk factors for suicidal behavior. It is therefore very likely that evidence in the future will show, replicate, and confirm some genetic risk factors for suicidal behavior of small effect, at least in some parts in the world. Being able to identify people who may be at a higher risk for suicidal ideation and/or behavior will have several implications. In particular, the possibility that we may be able to identify people potentially vulnerable to suicidal behavior will raise a number of ethical public policy issues (Meltzer, 2000): 1. First, as with any other investigation in mental health and in genetics, we must make sure that potential subjects in genetic research studies are able to provide informed consent. They have to be informed that their participation is voluntary, and that they may withdraw at any time. The risks and the benefits of the study must be clearly stated, and alternatives to the study should be made available to the participants. It may be necessary to explain genetic technology to participants before obtaining informed consent. 2. Second, it is very important to protect the confidentiality of data on individuals (both suicidal cases and their controls), from whom material for molecular genetic research studies of suicidal behavior is taken. 3. Third, in the case of possible collaborative research with the pharmaceutical industry, anyone involved in the genetic investigation of suicidal behavior should be aware of the separate and careful delineation of researcher and clinical roles.