How and Why Are Irritability and Depression Linked?

Based on its course over time, irritability is linked to depression cross-sectionally and longitudinally. Cross-sectionally, irritability takes an episodic form as a symptom in pediatric depression; yet, irritability in the absence of depressed mood or anhedonia is rare. Longitudinally, chronic irritability has been shown to predict depression rather than bipolar disorder or externalizing disorders. Evidence suggests that the link between irritability and depression is explained mostly by shared genetic risk. Both conditions are also associated with higher rates of family history of depression, childhood temperaments and personality styles, and negative parenting styles. The treatment implications are discussed.