Olivia Cooke as Amanda

Anya Taylor-Joy as Lily

Anton Yelchin as Tim

Paul Sparks as Mark

Francie Swift as Cynthia

Kaili Vernoff as Karen

Alyssa Fishenden as Jessica

Jackson Damon as Phil

James Haddad as Michael

Nolan Ball as Delivery Guy

Celeste Oliva as Receptionist

Stephanie Atkinson as Knitting Therapist (uncredited)

Lauren Laperriere as Mental Patient (uncredited)

Thomas Dings as Teenager (uncredited)

Leah Procito as Doctor (uncredited)

Alex Wolff as Party Friend (uncredited)

Xavier Dillingham as Party Goer (uncredited)

Jack Norton as Mental Patient (uncredited)

Daniel Martignetti as CT State Policeman (uncredited)