raised apart has been conducted, for example, and much remains unknown about non-genetic familial transmission of suicide.

Biological predictors of suicidal behavior should be sought through brain mapping studies. Prospective, rather than cross-sectional studies, are crucial. Analyses in vivo would allow the examination of changes over time to elucidate response to treatment and remission from episodes of mental illness. Moreover, brain mapping studies may help to identify individuals at risk for suicidal behavior.

  • Genetic factors are strongly related to liability for suicidal behavior, accounting for 30–50 percent of the variance. The genetic liability may be linked to the heritability of mental illness and/or impulsive aggression. However, family, cultural, and other environmental factors must be considered as independent factors. Family studies have shown that offspring of suicide attempters are much more likely to engage in suicidal behavior. Factors that increase the likelihood of transmission of suicidal behavior include the transmission of impulsive aggression and sexual abuse from parent to child. Therefore, offspring of parents who have made suicide attempts are at high risk for suicidal behavior and may inform us about the mechanisms of familial transmission, both genetic and non-genetic.

    Prospective studies of populations at high risk for the onset of suicidal behavior, such as the offspring of suicide completers or attempters, can allow for studies of neurobiologic, genetic, and non-genetic factors that predict the onset of suicidal behavior.

    Genetic markers that have functional significance and correlate with impulsive aggression and suicidal behavior cross-sectionally may have the potential to identify individuals at risk and help pinpoint treatment.

  • Adoption studies, twin studies, and family studies are effective approaches to elucidate the genetic liability for suicide and to assess both genetic and non-genetic influences. Candidate gene analyses suggest the genetic targets that influence suicidal behavior. New microarray technology can aid researchers in identifying genetic variations between suicidal and non-suicidal individuals. These approaches hold great promise for elucidating the risk factors for suicide and providing tools for its assessment, treatment and prevention.

Future research using these approaches should be pursued. Twin studies of suicidal behavior should examine familial transmission through genetic and non-genetic pathways and explore associations

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