Editorial: The Paradox of Reward Processing in the Association Between Irritability and Depression.

Irritability as part of depression has been studied for a long time; it was a cardinal symptom in Burton's concept of melancholia and an underlying mechanism toward oneself in Freud's description of melancholia. Today, irritability is considered a cardinal symptom of depression in children and adolescents by DSM-5, along with depressed mood and anhedonia, and is present in about 40% of youth with depression. Longitudinally, irritability has been shown to be a specific predictor of depression across development in several studies.1 The mechanisms underlying the close relationship between irritability and depression are unclear, but most evidence points to shared risk factors, including genetic risk, family history of depression, early temperament and personality, and parenting styles.2 However, other plausible shared mechanisms, especially those involving neural circuits, have been undertested.