Differential associations of phasic and tonic irritability to suicidality among U.S. adults

Research on the relations between irritability and suicidality among adults has rarely compared or differentiated between tonic versus phasic irritability. The current cross-sectional study investigated the role of both tonic and phasic irritability in relation to lifetime suicidal ideation, plans, and attempts. The study included adult participants who completed the suicidality module from the National Comorbidity Survey - Replication (NCS-R) (N = 7683 for suicidal ideation and N = 1223 for suicidal plan and attempt). The NCS-R used lay-administered, standardized diagnostic interviews. Phasic and tonic irritability were assessed with individual screener items from the World Health Organization Composite International Diagnostic Interviews (CIDI). The current study used logistic regression, weighted Cox proportional hazard model, and multinomial logit regression, adjusting for sex, race/ethnicity, age, education, and marital status. Both types of irritability were included simultaneously in the models. Results indicated that both types of irritability were significantly associated with increased odds of suicidal ideation (phasic: Odds Ratio 2.72 [2.35,3.14]); tonic: OR 2.34 [2.04,2.68]), age of first-time suicidal ideation (phasic: Adjusted Hazard Ratio 2.87 [2.27, 3.63]; tonic: AHR 2.12 [1.76,2.54]), and suicide attempt (phasic: OR 1.53 [1.13,2.07]); tonic: OR 1.44 [1.11,1.89]). Only tonic but not phasic irritability was associated with suicide plans (OR 1.39 [1.08,1.79]). When suicide attempts were divided into those that were impulsive versus planned and compared them to no suicide attempt, both types of irritability were associated planned attempts, (phasic: OR 1.53 [1.13,2.07]); tonic: OR 1.44 [1.11,1.89]) but only phasic irritability was related to impulsive attempts (OR 1.70 [1.10,2.64]). Phasic and tonic irritability show differential relations to and can serve as differential markers for suicide-related outcomes in adults.