Occupational and behavioral factors associated with fatigue among long-distance truck drivers on the Kenya-Uganda transport corridor.

Irritability describes proneness to anger and is characterized by chronically negative moods and disruptive behaviors (S. C. Evans et al., ; Moore et al., ). Clinically significant irritability affects as many as twenty percent of youth and ranks among the leading reasons children and families seek mental health treatment (Copeland et al., ; S. C. Evans et al., ; Mayes et al., ; Peterson et al., ). Irritability is also a marker of risk for future psychopathology, in particular adolescent mood and anxiety disorders (Dougherty et al., ; Sorcher et al., ), which are fueling the current crisis in child mental health (Benton et al., ). Critically, even in non‐clinical samples, elevated irritability is associated with greater functional impairment (Copeland et al., ), pointing to the importance of investigating the etiology of irritability to identify key targets for public health intervention and, ultimately, reshape symptom trajectories for irritable youth. In prospective longitudinal samples, childhood irritability has been independently linked with many individual types of stressful experiences including parental mental health issues (particularly depression), harsh parenting practices, and family dysfunction (Smith et al., ; Wiggins et al., ; Yu et al., ). Similarly, living in low income contexts also increases risk of irritability, possibly through exposure to stressful experiences (Lengua, ; Piotrowska et al., , ). In cohorts enriched for trauma exposure (Bielas et al., ; Cotter et al., ; Grasser et al., ; Henriksen et al., ; Hodgdon et al., ; McCoy et al., ; Zhan et al., ) or other forms of psychopathology, such as attention deficit hyperactivity disorder, anxiety, or depression (Hartman et al., ; Kessel et al., ; McCoy et al., ; Wakschlag & Keenan, ; Zendarski et al., ), exposure to psychosocial stress and family violence also predicts elevated irritability. Given that stressful life experiences are associated with irritability in both clinical and nonclinical samples, family stress and trauma exposure may represent critical targets for both prevention of and intervention on clinically significant irritability. Despite evidence of the importance of independent stressors to irritability in studies examining single stress exposures, many studies examining multiple stressors only investigate the effects of total stress exposure on irritability, that is, number of adverse childhood experiences (Felitti et al., ), limiting the ability to understand which specific stressors contribute to irritability. Three extant cross‐sectional studies show that exposure to interpersonal violence, and in particular psychological violence, is associated with increased irritability. Two studies recruited trauma‐exposed, treatment seeking youth, limiting their generalizability (Cotter et al., ; Grasser et al., ). The third study leveraged a community sample of adolescents ( = 7422, 13‐to‐19‐year‐olds) and showed that each of ten traumatic events (including physical and sexual violence) was independently associated with irritability. This study, however, did not examine changes in irritability over time, nor did it test the effects of multiple exposures concurrently, thereby limiting the understanding of how combinations of stressors contribute to irritability (Henriksen et al., ). Furthermore, only Cotter et al. () examined the effect of traumatic events in conjunction with other non‐traumatic psychosocial stressors (e.g., poverty).