he fourth season of Psych originally aired in the United States on USA Network from August 7, 2009 to March 10, 2010. It consisted of 16 episodes. James Roday, Dulé Hill, Timothy Omundson, Maggie Lawson, Corbin Bernsen, and Kirsten Nelson reprised their roles as the main characters. James Roday portrayed Shawn Spencer, a fake psychic detective who periodically consults for the Santa Barbara police department. A DVD of the season was released on July 13, 2010.

Overview from themoviedb.org