Major Depressive Disorder (MDD) is characterized by multiple symptoms including:

Major Depressive Disorder (MDD) is primarily defined by an extended period of depressed mood, which reflects a significant shift in an individual's emotional state and functioning. To meet the criteria for MDD, individuals typically experience a persistently low mood that lasts for most of the day, nearly every day, for at least two weeks. This symptom is central to the diagnosis and can manifest in various ways, such as feelings of sadness, hopelessness, or emptiness.

The duration and intensity of this depressed mood contribute to the overall impact of MDD on an individual's life, affecting their relationships, work performance, and overall well-being. Understanding this characteristic is crucial as it differentiates MDD from other mood disorders that may have different mood presentations or durations.

The other options present symptoms or conditions that are inconsistent with MDD. Excessive energy and euphoria typically characterize disorders such as bipolar disorder, while chronic fatigue with no mood disturbances does not fully align with the emotional and cognitive symptoms present in MDD.