Yes. Often, sadness and depression are confused. This is why some will use depression as a synonym for sad, but that isn't accurate (nor is it fair to those of us who battle depression). Depression doesn't mean always being sad. For some of us (many of us), it can come in the form of apathy. My depression comes in varying waves. Sometimes, it's an intense longing. Others, it is total apathy. An 'I don't care' attitude toward life. Nothing will be enjoyable anymore. Nothing can excite me. I become numb. Apathy can be a symptom of depression just as well as sadness. Neither are depression, but both can be symptoms.