No, they are not, but they are linked conditions. In other words, someone who suffers from a great deal of anxiety can go on to suffer from depressive states. However, you do not need to suffer from anxiety to feel depressed. Both mental health conditions have similar symptoms which is why they are sometimes incorrectly lumped together. For instance, people with anxiety will often suffer from tiredness, weight loss, insomnia and muscle tension. All of these physical manifestations of anxiety can also be detected in people who are clinically depressed, too. Some medical professionals will treat both disorders as a single entity where the symptoms are so closely bound as to be indistinguishable. This is often referred to as mixed anxiety and depressive disorder, otherwise known as MADD.