What symptom is essential for diagnosing a major depressive episode?

For diagnosing a major depressive episode, the criterion of loss of interest in daily activities, also known as anhedonia, is essential. This symptom is one of the core diagnostic criteria outlined in the Diagnostic and Statistical Manual of Mental Disorders (DSM-5). It reflects a significant change in functioning and is often more indicative of the disorder than other symptoms. Individuals with major depression typically experience a profound lack of pleasure or interest in activities that they once found enjoyable, which can significantly impact their quality of life and daily functioning.

While other symptoms such as difficulty concentrating, feelings of worthlessness, and sleep disturbances (insomnia or hypersomnia) may accompany major depressive episodes, they are not considered essential for diagnosis. Instead, the presence of anhedonia is a hallmark of the disorder and plays a crucial role in its identification and subsequent treatment. The emphasis on this symptom aligns with the understanding that the essence of depression is a pervasive low mood and loss of interest, affecting one's motivation and ability to engage in life.