Mugwort herb was used to construct the fake brick of marijuana.
While watching the finale to The Last Man on Earth (1964), when Dr. Robert Morgan (portrayed by Vincent Price) dies, Lisa says "Not Dr. Robert...he does everything he can..." This is a reference to a lyric in the Beatles song "Doctor Robert." The song is about drugs, and Lisa and Sam eat a marijuana cookie previously while watching the movie.
The book being read by Lisa when Sam returns from speaking with Deb is "Armageddon Paradox" by "Lisa" writer Eric Winkler's father, Peter F. Winkler.
When Jessica and Millie speak to Deb on the phone, a poster for Arbor Demon (2016), which was also directed by Patrick Rea, can be seen on the wall. Next to it is a poster for Starry Eyes (2014), which is cited by writer Eric Winkler as an inspiration for "I Am Lisa."
"Gretchen Glendon's" surname is an homage to "Lisa Glendon," portrayed by Valerie Hobson in Werewolf of London (1935).