Suicide and Self-Harm: Genetic and Environmental Influences Overlap

MedicalResearch.com Interview Invitation
Karin J. H. Verweij, PhD
Department of Developmental Psychology and EMGO Institute for Health and Care Research,  VU University
Amsterdam, the Netherlands

MedicalResearch.com: What are the main findings of the study?

Dr. Verweij: We performed a twin study using over 10,000 adult Australian twins to determine the relative importance of genetic and environmental influences on individual differences in non-suicidal self-injury (NSSI) and suicidal ideation and their covariation.

We found that individuals that report self-harm are approximately eight times more likely to also report suicidal ideation. Results from the bivariate genetic model indicated that the substantial correlation between non-suicidal self-injury and suicidal ideation (r=0.49 for males and 0.61 for females) is largely explained by overlapping genetic factors: 62% and 76% for males and females, respectively. Overlapping residual influences, including nonshared environmental influences and measurement error, also explain part of the covariance between the two traits. These findings suggest that the two behaviors share similar biological underpinnings.

MedicalResearch.com: What should clinicians and patients take away from your report?

Dr. Verweij: This study showed that there is a high comorbidity between non-suicidal self-injury and suicidal ideation, and this comorbidity is for a substantial part due to overlapping genetic influences. An important implication for clinicians and patients is that individuals that engage in non-suicidal self-injury are at risk for also developing suicidal behaviors. Early intervention targeting non-suicidal self-injury should therefore also focus on preventing suicidal behaviors.
MedicalResearch.com: What recommendations do you have for future research as a result of this study?

Dr. Verweij: Future research should further investigate which genetic and environmental influences underlie the vulnerability in NSSI and suicidal ideation. Studies may focus on both the overlapping genetic and environmental influences as well as on the influences that are unique for each behavior. There are currently not many studies that directly compare non-suicidal self-injury and suicidal behaviors; identification of the overlapping and unique risk factors will be valuable for developing effective prevention and intervention strategies.

Citation:
Overlapping Genetic and Environmental Influences on Nonsuicidal Self-injury and Suicidal Ideation: Different Outcomes, Same Etiology?

Dominique F. Maciejewski, BSc; Hanneke E. Creemers, PhD; Michael T. Lynskey, PhD; Pamela A. F. Madden, PhD; Andrew C. Heath, PhD; Dixie J. Statham, DPsych; Nicholas G. Martin, PhD; Karin J. H. Verweij, PhD

JAMA Psychiatry. Published online April 23, 2014. doi:10.1001/jamapsychiatry.2014.89