OBJECTIVE

To determine which sleep variables, including sleep duration, sleep quality, insomnia symptoms, and nightmares, were significantly and independently associated with subsequent adolescent suicidal behavior and non-suicidal self-injury (NSSI).

METHODS

A prospective longitudinal study was conducted in Shandong, China. Participants were 7,072 adolescents initially assessed in November and December in 2015 and reassessed 1 year later in 2016. Self-administered structured questionnaires were used to assess suicidal behavior, NSSI, night sleep duration, insomnia symptoms, sleep quality, nightmares, impulsivity, depression, and family demographics. Logistic regression analyses were performed to examine the associations between sleep variables and suicidal behavior and NSSI.

RESULTS

At 1-year follow-up, 190 participants (2.7%) attempted suicide and 621 (8.8%) engaged in NSSI. Insomnia symptoms and frequent nightmares (several times a month) at baseline were significantly associated with subsequent suicide attempt and NSSI 1 year later. After adjustment for covariates including adolescent and family demographics, depression, impulsiveness, and prior suicide attempt/NSSI, frequent nightmares in the past year remained significant for suicide attempt (OR = 1.96; 95% CI, 1.15-3.33) and NSSI (OR = 1.52; 95% CI, 1.10-2.08). With further adjustment for insomnia symptoms, sleep quality, and sleep duration, the associations between frequent nightmares and subsequent suicide attempt and NSSI had almost no change. Insomnia, short sleep duration, and poor sleep quality were not independently associated with subsequent suicide attempt and NSSI.

CONCLUSIONS

Frequent nightmares were independently associated with subsequent suicide attempt and NSSI among adolescents. Assessing and intervening for nightmares may have important implications for early identification of adolescents at risk and prevention of adolescent self-harm and suicide.