Learning what "makes people tick" is part of the fascination of psychology. Unfortunately, that fascination can quickly be dulled, especially for younger students, by the weight of the profession's clinical literature. Although the case studies of Freud, Jung and modern scientists such as Oliver Sacks are eminently readable, they're not typical of the genre. Literary fiction can complement traditional texts by illustrating a wide variety of psychological traits and conditions in an inherently interesting, readable manner. In most psychological disciplines, it's possible for the instructor to select literary works that illustrate the points under discussion during the course.
When selecting a literary work to illustrate your course materials, consider both its applicability and the reading level of your students. If you are considering the psychology of gender, for example, you might choose either Virginia Woolf's "Orlando" or Ursula K. LeGuin's "The Left Hand of Darkness." The Woolf novel, about an Elizabethan courtier who begins life as a man but inexplicably becomes female, is better suited to advanced or college-level students. The LeGuin, a science-fiction novel of a planet where the people are genderless except during their monthly reproductive cycle, is more accessible to high schoolers.
Determine in advance what your goal is for the assignment. You might choose to have your students select a number of characters from the work and categorize their psychological condition. For an alternative approach, you might assign each student a single character, such as Raskolnikov from Dostoyevsky's "Crime and Punishment," and have them explain the development of his psychological state through the novel. For a more challenging project, have them analyze an unreliable narrator, such as the protagonist of Kazuo Ishiguro's "A Pale View of Hills."
A potential criticism of literary works as a teaching tool is that they can be misleading. While the characters can present vivid and apparently realistic examples of specific behaviors or psychological conditions, it's important to remember that they are not real, living people and their actions are limited by the author's imagination. However, this apparent weakness can constitute an important strength. It requires students to exercise critical thinking, exactly as they would when interviewing a patient or research subject. If you can guide them to an understanding of this during classroom discussions, their education will be enriched by it.