There are two cognitive explanations for depression: Beck's negative triad and Ellis' ABC model
Beck suggested a person develops a dysfunctional view of themselves (negative self-schema) and thus becomes depressed due to 3 types of negative thinking, these three elements make the negative triad: Negative view of the world, future and self
Negative view of the world can consist of thoughts such as: There is nothing good in the world and thus no hope
Negative view of the future: Nothing good will happen in the future, reduces hopefulness and enhances depression
Negative view of the self: the individual will believe they are a failure and hold no good thoughts, this enhances existing depressive feelings and confirms an individuals feelings of low-self esteem
Ellis' ABC model proposed that depression occurs when an activating event, triggers an irrational belief - leading to a consequence (an emotional response, like depression).
Ellis identified, three types of irrational beliefs: Musturbation (the need to achieve perfection) I CANT STAND IT ITIS (The view of something to be a major disaster when it doesn't go smoothly) and Utopianism (the belief that life is always meant to be fair)