Genetic influences on non-suicidal self-injury and suicidal thoughts and behaviors

Abstract

[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT REQUEST OF AUTHOR.] Though non-suicidal self-injury (NSSI) and suicidal thoughts and behaviors (STBs) often co-occur, very little is known about the shared and unique genetic influences on these behaviors. Previous research has suggested that shared genetic liability may contribute to covariation in NSSI and suicidal ideation, as well as NSSI and suicide attempts. The present study expanded upon these findings by examining overlapping and unique genetic liability shared across NSSI, suicidal ideation, and suicide attempts. Behavioral genetic analyses were employed using existing data from the Childhood Trauma Study, a large population based study of Australian twins. Results indicated that lifetime NSSI increased the likelihood of reporting lifetime STBs. Biometric analyses found that seventy two percent of the genetic variation in NSSI overlapped with suicide attempts, while only eighteen percent overlapped with suicidal ideation. Suicidal ideation, but not NSSI or suicide attempts, had significant unique genetic variance remaining after accounting for genetic influences common to all three. Results suggest that NSSI and suicide attempts in particular share a common genetic liability, while suicidal ideation is largely affected by genetic influences distinct from NSSI and suicide attempts. Future directions and implications for prevention are discussed.