Yes, depression is a mental illness.
It is one of the most common mental illness in our society today. Depression is also called "major depressive disorder", "clinical depression" or "major depression". It is a serious medical illness that needs professional diagnosis and treatment.
People with depression are often in a depressed mood, have poor sleep, they have loss of intrest, they feel guilty and have feelings of worthlessness, concentration problems, poor appetite, weight changes, energy loss and suicidal ideation.
Depression is a mental disorder. This makes people experience sadness for prolonged periods of time. There are some people who do not even know why they are feeling depressed but they know that they are experiencing it. People with depression also experience some differences in their appetite. They may suddenly develop a huge appetite or they may not eat anything at all.
People who are depressed may try to isolate themselves from everyone else simply because of their own personal reasons. They may have trouble concentrating even with the most simplest instructions. Take note that being depressed is different from just being sad or lonely. This is something that can be hard to go through especially when the depressed person is alone.