History and geography of suicide: Could genetic risk factors account for the variation in suicide rates?

The current state of knowledge of genetic predisposition towards the suicidal behavior allows for a question whether genetic risk factors account for the variation in suicide rates through time and space. Accordingly, the presented study will attempt to tackle the genetics behind suicidal behavior from the perspective of the populational genetics, First, the variability of suicide rates across Europe is discussed. This is followed by a brief discussion of the J curve (on a map of Europe, the countries with a higher suicide rate form a so-called J curve, which starts in Finland and extends down to Slovenia), which maps on to the second principal component identified for European gene distribution, representing the ancestral adaptation to cold climates and the Uralic language dispersion. Furthermore, we will discuss whether the group of people living within the J-curve could share genes, which may not tolerate excessive amounts alcohol, the combination of which is more likely to end in suicidal behavior. Further along we list possible ways in which suicidal behavior could have been selected for genetically in populations and identify those specific populations in which it may have appeared. Finally, we point at other locations in the world where a similar interplay of genes and environment has probably occurred, Greenland being the best example of the malignant interaction of alcohol consumption and the trait-like characteristics, which might constitute the vulnerability to suicidal behavior. (C) 2005 Wiley-Liss, Inc.