Final answer:
Depression and anxiety are the two most common disorders in the United States, with anxiety disorders affecting about 18% of adults annually and depression affecting roughly 10%.
Step-by-step explanation:
The two most common disorders in the United States are depression and anxiety. Anxiety disorders, which include conditions like obsessive-compulsive disorder (OCD), panic disorders, posttraumatic stress disorder (PTSD), social and specific phobias, are the most prevalent, affecting nearly 18% of U.S. adults annually.
Mood disorders, with depression being the prominent condition, are the second most common, affecting roughly 10% of U.S. adults each year. Depression is a long-term, debilitating illness, characterized by a severely depressed mood lasting longer than two weeks, among other symptoms. Anxiety disorders are characterized by feelings of worry and fearfulness that persist for months. Therefore, the correct answer to the question is 'd. depression and anxiety'.