He just wants something to numb the pain, and that something is a gun.
He wants the pain to end. The pain of his parent's divorce. Of being bullied every day. Od never measuring up to his oh so perfect brother. Of always being alone. It's too much for him. It needs to end now. There's no way around it.
Sure, he's dealt with it, for years. It's only ever gotten worse, and never better, and he can't seem to see the light at the end of the tunnel that everyone's always talking about. Now he knows what he has to do. There's only one way to end his pain.
His note's written. He puts the gun to his head and pulls the trigger. This is my Novocaine. Was his last thought before his brain and blood splatters the walls as his lifeless body falls to the floor, the gun sliding out of his limp hand.
Poor Gerard was just another victim of circumstance. But at least in the end he got his Novocaine.