Autobiographical memory and early-onset depression : insights from the environment, genetics and brain structure

• Main Author: Warne, Naomi
• Published: Cardiff University 2018
• Online Access: https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.768072

Difficulty remembering specific events from the personal past, known as overgeneral autobiographical memory (AM), has been associated with adult depression. However, evidence for overgeneral memory as a risk factor for early-onset depression is less consistent, and the aetiology of overgeneral memory is not well understood. The aim of this thesis was to examine whether overgeneral memory could be a risk factor or risk mechanism for early-onset depression. I first examined the cross-sectional and longitudinal relationships between overgeneral memory and depression. Overgeneral AM to negative cues was associated with cross-sectional depressive symptoms and depressive symptoms three years later, thereby indicating temporal precedence. I also assessed whether overgeneral memory was a risk mechanism through which known risk factors for depression (stressful life events (SLEs) and genetic risk) exert their effects. Although overgeneral memory was associated with SLEs, it did not mediate the relationship with depression. Instead, results suggested overgeneral memory and SLEs exert independent effects on subsequent depression. In contrast, overgeneral memory was not associated with common genetic risk for depression. Finally I investigated whether white matter connections in the brain could help explain the link between overgeneral memory and depression. White matter tracts previously associated with depression were linked to specific AMs that were positive in content but not to other measures of AM. In combination, these finding suggest that overgeneral memory is a risk factor for early-onset depression although observed effect sizes were small. Thus, targeting overgeneral memory could be useful for treatment and prevention of early-onset depression. Overgeneral memory was not a mechanism for known risk factors of depression (SLEs and genetic risk). The association with white matter tracts involved in depression provides preliminary evidence that overgeneral memory could be a risk mechanism for depression. Nevertheless, preliminary evidence from this small cross-sectional study requires replication in larger, longitudinal studies.