If I had to rely on psychology for what I know about people, it would be pitifully thin.
Sources that I have found useful in my understanding of the human condition, including freedom, guilt, and responsibility:
Homer, Sophocles, Aeschylus, Ovid, Augustine, Old and New Testaments (especially the Gospels), St. Paul (esp., the Letter to the Romans), St. Augustine, M. Luther, J. Calvin, T. Hobbes, Shakespeare, R. Schleiermacher, S. Freud, Rheinhold Neibuhr, P Tillich, K. Barth, R. Bultmann, W. Dilthey, W. Whitman, S. Kierkegaard, William James, R. Otto, Heidegger, JP Sartre, A.N. Whitehead, John Hick, John Macquarrie, CG Jung, T. Leary, Ernest Becker, K. Vonnegut, and Mircea Eliade.
The only (American) psychologists on this list are William James and T. Leary. GH Mead, S. Tomkins, RJ Lifton, and E. Goffman probably belong on the list.