Which psychiatric disorder is characterized by significant feelings of sadness and loss of interest in life?

The correct choice is characterized by persistent feelings of sadness that can last for weeks or even longer. Individuals with this disorder often experience a noticeable decrease in interest or pleasure in activities they previously enjoyed. These feelings can impact daily functioning, making it difficult for individuals to carry out normal tasks such as going to work or engaging in social interactions.

In addition to feelings of sadness, this disorder can also involve other symptoms such as changes in sleep patterns, appetite, and energy levels, as well as feelings of worthlessness or guilt. This comprehensive picture is what distinguishes it from the other disorders listed.

In contrast, the other options involve different sets of symptoms. Anxiety disorders typically include excessive worry and fear but may not include the pervasive sadness characteristic of depression. Bipolar disorder involves alternating episodes of depression and mania, rather than solely depressive symptoms. Obsessive-compulsive disorder focuses on intrusive thoughts and compulsive behaviors rather than significant sadness and lack of interest.