Methods: The sample (N=48) comprised 81% females, 71% heterosexual youth, mean age was 15.8 (SD = 0.95) recruited from an inpatient psychiatric unit in the northeastern US. The racial and ethnic composition was 67% White and 77% Non-Hispanic/Latino. Past 90-day SA, SP, and NSSI were measured using the Timeline Follow Back Calendar (TLFB). The TLFB collects information using a calendar format with temporal cues to assist in recall of days when suicidal and nonsuicidal thoughts and behaviors were present. Full maximum likelihood was used for all analyses. Population-average fixed effects are reported.
Results: First, the odds of SP increased across the 90 days leading up to hospitalization (b=3.40, OR=30.03, 95% CI [15.84, 56.95]). The odds of NSSI remained stable across the 90 days leading up to hospitalization (b=2.14, OR=8.48, 95% CI [3.71, 19.38]). In addition, there was a significant association between the two trajectories (r=.264, p<.01), indicating that increasing odds of SP leading up to hospitalization was associated with increasing odds of NSSI during that same period. Second, both SP (b=3.40, OR=29.96, p<.001) and NSSI (b=2.13, OR=8.41, p<.001) predicted elevated odds of SA, when the predictor occurred on days in which the other did not occur. Third, there was a significant interaction between SP and NSSI in predicting SA such that when both occurred together on the same day, the odds of SA were weakened (b=-2.77, OR=0.06, p=< .001).
Conclusions: Results indicate that on days when youth engaged in either NSSI or SP their odds of attempting increased on that same day. However, on days when youth engaged in both NSSI and suicide planning, their odds of attempting weakened. Based on our findings, it is possible that NSSI serves as a mechanism for youth to regulate their emotions on days when they are at potentially higher risk of attempting suicide (given their suicide planning). Future research should continue to explore the complex associations between NSSI and suicide attempts.