Symptoms of depression create both stress symptoms and symptoms of anxiety. The reason for this is that depression decreases our stress tolerance. Things that previously would not seem like worthy of worry become a source of stress symptoms and symptoms of anxiety when suffering from a clinical depression.
Panic attacks make you feel crazy and yet they can leave as fast as they come. Many people have one or two panic attacks during a time of stress and then don't have them again for a long time. Panic sufferers also find that when they finally admit they are having panic attacks, they are surprised to find just how many people they know have also had them. But one of the classic symptoms of depression is social withdrawal. Therefore, a person suffering from the symptoms of depression is more likely to feel isolated alone in their experience of panic attacks because they are not around people as much to find out just how common panic attacks really are.
There are also many people who struggle with them frequently. One of the problems in coping with them is the way that depression supplies fuel for them. Panic thrives on the feeling of being off balance and depression does a real fine job of making people feel off balance.
One of the problems in attacking anxiety and depression in our lives is that anxiety and depression gather strength for each other. Depression depletes our energy, robs us of the enjoyment of simple pleasures (and big ones), and often makes it difficult for people to stay asleep past 3 or 4 am. Anxiety ramps us up with an adrenaline rush or it gives fake energy caused by low-grade stress response that doesn't seem to have an off switch. Furthermore, anxiety often makes it difficult to fall asleep. Anxiety cuts our sleep short at the beginning of the night and depression cuts it off at the end of the night. Finally, when we are attacking anxiety and depression, we find that we are handicapped by these effects precisely at the moment when we need everything going for us.
One of the reasons that anxiety and depression make such a good team is that anxiety thrives on our sense of being unsafe, weak, and vulnerable to danger. The danger can be real or imagined. It can be tangible or intangible. Now here is the kicker: depression depletes us, makes us feel weak, unsafe, and vulnerable. In other words, depression creates the precise environment in our emotional landscape that makes anxiety grow like a weed in fresh potting soil.