Psychologists and psychiatrists are experts in diagnosing depression, based on the symptoms. Typically, a depressed person is melancholy, either loses his appetite or overeats, and in some cases, he will not feel like spending time with people. This hermit-type symptom of depression is usually attributed simply to the person being in the blues so much that he just is not in the condition to socialize, which is actually understandable.
But do you know there is an underlying cause why depressed people prefer to hide away from people? If you have ever felt that way, you might recall some of the thoughts that crossed your mind that led you to want to stay away from people. Possible causes would be that you kept getting hurt and frustrated by other people, or that you yourself, during your whole depressed phase, only kept lashing out at other people anyway that you decided staying away would keep you from continuing to hurt the ones you love.
In this case, there is actually a deeper root behind your depression. Could it be that behind your strong façade, you are struggling with condemnation?