Final appearance of Sam Anderson as Dr. Jack Kayson. He has appeared in 20 episodes beginning in the first season.
First appearance of Dr. Harold Zelinski, who would recur for the rest of the season for a total of 11 episodes. However his portrayer (Steven Christopher Parker) previously appeared in 11.16 ("Here and Now") as a different character named Gus.
First appearance of Reiko Aylesworth as Chaplain Julia Dupree.
The title is from the legal term "driving under the influence" which is the act of operating a motor vehicle after having consumed alcohol or other drugs to the impairment of one's motor skills.
Dr. Gregory Pratt (Mekhi Phifer) is talking to Harold Zelinsky (Steven Christopher Parker) about music and Greg mentions Eminem. Mekhi Phifer playing as Dr. Gregory Pratt happens to work with Eminem in 8 mile (2002)