Andy Serkis as Dr. Adrian King

Thomas Brodie-Sangster as Donald Clarke

Michael McElhatton as James Clarke

Sharon Horgan as Renata Clarke

Aisling Loftus as Shelly

Ronan Raftery as Jeff

Sean Duggan as Teacher

Enda Oates as English Teacher

Emma Eliza Regan as Morna

Jessica Schwarz as Tanya

Lilly Forgách as Shrink #1

Ian Fitzgibbon as Shrink #2

Ben Harding as Michael

Killian Coyle as Hugo

Andrea Thompson as Sharon

Peter Sexton as Billy

Jane Brennan as Dr. Johnson

Aisling Bodkin as Joanna

Ned Dennehy as The Glove

Dónal Haughey as Guy at Laptop

Simon Mulcahy as Teenage Guy

Holly Gregg as Maja

Mella Carron as Wendy

Julie Sharkey Carpenter as Nurse

Billy Gibson as Rugby Jock

Mary Murray as Prostitute #1

Rachel Dunne as Prostitute #2

Joe Dermody as Patient in Hospital

Christine Cotter as Patient in Hospital

Warren Farrell as Patient in Hospital

Christopher Doyle as Patient in Hospital

Alan Bradley as Patient in Hospital

Theo Fitzgibbon as Teenage Crowd

Eliza Fitzgibbon as Teenage Crowd

Kitty McLaughlin-Dunning as Teenage Crowd

Saoirse Benson as Teenage Crowd

Matthias Beier as The Glove

Olga Wehrly as Nursey Worsey

Amelia Crowley as Nursey Worsey

Nina-Friederike Gnädig as Nursey Worsey

Amy Huberman as Nursey Worsey