Most people think they know the symptoms of depression, but you would be surprised by how tricky thing get. You can be depressed for a long time without even knowing it. The most obvious symptoms of depression, of course, are known by everyone. The feeling of being sad all the time and unmotivated, having thoughts of suicide, and withdrawing from your friends are the best signs. But in reality, depression symptoms are much broader than this. People do their best to cope with being depressed, and so sometimes you can be in the middle of a rather severe malaise without even knowing it. One of the most classic symptoms of depression, for example, is depressed mental function.