Which of the following is one of the most common psychiatric conditions characterized by deep feelings of sadness?

Depression is recognized as one of the most common psychiatric conditions, primarily defined by persistent feelings of sadness, hopelessness, and a lack of interest or pleasure in previously enjoyed activities. Individuals experiencing depression may also struggle with various cognitive, emotional, and physical issues, which can significantly impair their daily functioning. The intensity and persistence of these feelings are what distinguish depression from transient feelings of sadness that everyone might experience at times.

Bipolar disorder encompasses episodes of both depression and mania, presenting a more complex condition characterized by shifts between elevated moods and depressive episodes. Schizophrenia is a severe mental disorder that affects how a person thinks, feels, and behaves, often involving delusions and hallucinations, rather than just sadness. Phobias are specific anxiety disorders involving intense fear of particular situations or objects, which is distinctly different from the pervasive sadness associated with depression. Thus, depression stands out as the primary condition defined by deep, lingering sadness.