Suicidal ideation and suicide attempt (suicidality) are common in adolescence and a public health concern. Childhood depression is a key risk factor for later suicidality and often co-occurs with irritability. No study to date has examined the joint association of depressive mood and irritability during childhood with later suicidality.Objective
To investigate the association of childhood irritability and depressive/anxious mood profiles with adolescent suicidality.Design, Setting, and Participants
This population-based cohort study included 1430 participants in the Québec Longitudinal Study of Child Development. Participants underwent assessment yearly or bi-yearly (5 months to 17 years). Data were collected from March 16, 1998, through July 17, 2015.Exposures
Profiles defined by the joint developmental trajectories of irritability and depressive/anxious mood at 6 to 12 years of age.Main Outcomes and Measures
Self-reported past-year suicidality (ie, serious suicidal ideation or suicide attempt) at 13, 15, and 17 years of age. Irritability and depressive/anxious mood were assessed using teacher report 5 times from 6 to 12 years of age.Results
The study included 1430 participants (676 boys [47.3%] and 754 girls [52.7%]) followed up to 17 years of age. Group-based multitrajectory modeling identified the following profiles: combined no irritability and low depressive/anxious mood with low irritability and low depressive/anxious mood (831 [58.1%]; reference group), moderate irritability and low depressive/anxious mood (353 [24.7%]), high depressive/anxious mood only (94 [6.6%]), and high irritability and depressive/anxious mood (152 [10.6%]). Children with high irritability and high depressive/anxious mood reported higher rates of suicidality (25 of 152 [16.4%]) compared with the group with the lowest symptom levels (91 of 831 [11.0%]). In logistic regression analyses, the high irritability and depressive/anxious mood profile (odds ratio [OR], 2.22; 95% CI, 1.32-3.74; number needed to be exposed [NNE], 18) was associated with suicidality. To a lesser extent, the moderate irritability and low depressive/anxious mood profile was also associated with suicidality (OR, 1.51; 95% CI, 1.02-2.25; NNE = 48). The high depressive/anxious mood only profile was not associated with later suicidality (OR, 0.96; 95% CI, 0.47-1.95; NNE = −320). The high irritability and depressive/anxious mood profile was associated with a higher suicidal risk compared with the depressive/anxious mood only profile (OR, 2.28; 95% CI, 1.02-5.15). Girls with the high irritability and high depressive/anxious mood profile had higher risk for suicidality (OR, 3.07; 95% CI, 1.54-6.12; NNE = 5).Conclusions and Relevance
Children with high irritability and depressive/anxious mood and, to a lesser extent, with moderate irritability only had a higher suicidal risk during adolescence compared with children with low symptom levels. Early manifestation of chronic irritability during childhood, especially when combined with depressive/anxious mood, may be associated with an elevated risk for adolescent suicidality. The putatively causal role of irritability should be investigated.