Depression is a mental illness characterised by extreme sadness and usually people suffering with it are full of guilt but cannot always state why they feel that way. Depression has become a fairly common mental illness as Kessler et al (1994b) found that around 17% of people will experience a major episode of depression during their life.
Due to the growing numbers of people suffering and potentially going to suffer from depression, it is important to understand the causes of depression. Memory has been identified as having a role in the onset and course of depression, specifically autobiographical memory. Autobiographical memory consists of our life experiences, although there is a cross-cultural difference between the types of memories which are encoded.
Research has shown that memory is malleable and has a tendency to inaccurately reconstruct the past (Loftus and Palmer, 1997), however this does not stop the human mind having an ability to reconstruct past events with great detail. Research suggests that depressed people have difficulty remembering specific events, instead they are much more likely to over-generalise their memories of specific negative instances into prolonged periods of time which are more consistently negative than they were in reality.
The effects of mood on memory have been shown to improve recall if the person is in the same emotional state as they were when the memory was encoded. This means that a person who has become depressed because of a recent event is likely to remember more negative rather than positive memories and therefore prolong depression.
Research has shown that depressed people appear to have a bias in the speed in which they recall positive and negative memories, negative memories being much easier to retrieve despite depressed people having no more objectively depressing experiences compared with a person who is not depressed. There is evidence that suggests that
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