Irritability Is Associated with Illness Severity and Anhedonia Is Associated with Functional Impairment Among Depressed Children and Adolescents

Objectives: Irritability and anhedonia are cardinal symptoms of depression for children and adolescents. However, anhedonia may be more strongly associated with illness severity compared with irritability. The present study evaluated the impact of irritability and anhedonia on symptom severity and functional impairment among depressed children and adolescents. Methods: Participants were 383 children and adolescents presenting for outpatient treatment at a community mental health center or academic medical center. Children and adolescents were diagnosed with unipolar depression or bipolar disorder. Regression models predicted depression severity and functional impairment from irritability and anhedonia after covarying age, gender, depressive and hypomanic symptoms, and diagnosis. Results: Greater irritability and anhedonia were associated with more severe depression symptoms. Greater irritability, but not anhedonia, was associated with lower global functioning and family quality of life (QoL), and more externalizing problems. Greater anhedonia was associated with lower overall, emotional, self-esteem, and social QoL. Neither irritability nor anhedonia was associated with school or physical QoL, nonsuicidal self-injury, suicidal ideation, number of comorbid diagnoses, or internalizing problems. Conclusions: Irritability was associated with more markers of depression severity, whereas anhedonia was associated with indicators of functional impairment. This study used a cross-sectional observational design and therefore cannot provide information about cause and effect relationships between variables. Irritability and anhedonia were derived from their respective subscales of the General Behavior Inventory and included only caregiver-reported symptoms but not child- or adolescent-reported symptoms. Identifying the impact of specific symptoms of depression may assist clinicians in delivering more individualized interventions to target symptoms that result in greater impairment.