The Shrink Next Door

Paul Rudd portrays the character Ike, a successful New York City businessman who seeks therapy from his neighbor, Dr. Isaac 'Ike' Herschkopf.

Will Ferrell plays the role of Marty Markowitz, a patient of Dr. Herschkopf who becomes emotionally dependent on his therapist and develops a peculiar relationship with him.

Kathryn Hahn portrays Phyllis Shapiro, Ike's younger sister who becomes concerned about her brother's relationship with Dr. Herschkopf.

Casey Wilson plays Bonnie Herschkopf, the wife of Dr. Herschkopf who becomes entangled in the complex dynamics between her husband and his patients.

Cornell Womack portrays Bruce, a close friend of Marty Markowitz who becomes suspicious of Dr. Herschkopf and his motives.

Robin Bartlett plays Cathy, a patient of Dr. Herschkopf who also becomes emotionally dependent on him.

Carey Moulder has an uncredited role as the White Party Waiter, a character who appears briefly in the show.

Christina Miller also has an uncredited role as Ms. Commuter, another minor character in the series.