Ellis proposed the A-B-C three stage model, to explain how irrational thoughts could lead to depression. The A stands for an activating event (e.g. you pass a friend in the corridor at school, and he/she ignores you, despite the fact you said ‘hello’). The B stands for beliefs, which can be either rational or irrational (e.g. an irrational interpretation of the event might be that you think your friend dislikes you and never wants to talk to you again). The C stands for consequences, and according to Ellis, irrational beliefs lead to unhealthy emotional outcomes, including depression (e.g. I will ignore my friend and delete their mobile number, as they clearly don’t want to talk to me).