Anxiety disorders are, by far, the most common psychological disorder. There are 6 major types of anxiety and research has determined that 15-19% of individuals have experienced clinical levels in at least one anxiety category.
These types include Generalized Anxiety Disorder (characterized by six months of excessive worry/anxiety, muscle tension, sleep problems, fatigue, and autonomic restrictors such as image avoidance), Social Anxiety Disorder (the most common form with about 13/3% of the population experiencing symptoms at some point. It is marked fear of social/performance situations, such as going to crowded places, peeing in public, etc), Panic Disorder (a condition in which individuals experience multiple uncued or (the attack is uncontrolled by the patient and often unknown when they may have one ) panic attacks and worry about these attacks for over one month), Type I Obsessive Compulsive Disorder (characterized by obsessions that cause anxiety and compulsions used to alleviate it), specific phobias, and post-traumatic stress disorder.Depression disorders are also, by far one of the most common, if not the most common psychological disorders.
Depression and Anxiety can also, be a dual diagnosis. Meaning you can have both at the same time.