There are a few different cognitive distortions that a course of CBT will try to identify. In the main, these can be thought of as erroneous or self-destructive modes of thought. For example, if you receive a letter and think it will contain some terrible news or nasty comment about you even before you open it, then this would be considered a cognitive distortion, especially if it led to an unwanted behaviour, such as drinking excessively or arguing with those around you. Essentially, CBT tries to identify such thought processes and help patients to notice them when they occur so that the same behavioural patterns are avoided. In the main, cognitive distortions come down to being excessively negative, thinking about things in a generalised or prejudicial way or having thoughts that tend towards catastrophic outcomes rather than more realistic ones.