There should always be screening for the comorbidity of major depression and anxiety disorders if a patient meets the criteria for either one of these disorders because the existence of either one could mask the existence of the other. The reason for this masking effect is the overlap of some of the symptoms that depression or anxiety causes. The reason for a patient to have comorbidity but be diagnosed with only one disorder is caused by the misconception that once the first disorder has been discovered, the patient’s diagnostic work is complete.