There is a big difference between depression and being lazy. When you are lazy, you have no motivation and do not do anything. When you have depression, you also have no motivation and do not do anything, but you also have multiple other symptoms, including low moods, irritability, sleep problems, feelings of guilt and hopelessness, low energy level, poor concentration, poor appetite, and suicidal thoughts. So as you can see, depression has many more symptoms, while being lazy does not have all those other problems associated with depression.
