Jamal is taking several honors courses this year and feels more pressure than he ever has before. He worries constantly about school, and because of the time he must devote to studying, he also worries about his relationship with his girlfriend. He is often restless, and his family thinks he gets irritated more than he used to. Even though he feels academic pressure, he often struggles to stay focused on his schoolwork, and his grades are suffering. Jamal's problems are most consistent with which of the following disorders?