What is a key characteristic symptom required for a diagnosis of Major Depressive Episode?

A key characteristic symptom required for a diagnosis of a Major Depressive Episode is a loss of interest or pleasure in activities that were previously enjoyed, often referred to as anhedonia. This symptom is central to the diagnosis because it reflects the pervasive and persistent nature of depression, impacting a person's ability to experience joy or engagement in life.

In the context of a Major Depressive Episode, the individual typically struggles with feelings of sadness, emptiness, or hopelessness, and the loss of interest in pleasurable activities is a hallmark feature indicating the severity of their condition. It underscores the emotional and cognitive disturbances associated with depression, highlighting the disorder's debilitating effects on overall functioning.

The other options, such as increased energy, excessive joy, and consistent cheerfulness, are contrary to the experiences typically associated with Major Depressive Episodes. Individuals with depression often report low energy levels and diminished mood, rather than elevated spirits or increased vitality.