A study in which nearly 50 participants consumed either alcohol (.4 or .8 g/kg, around 2 or 4 glasses of wine) or a placebo drink, performed a memory task, then were shown a video of serious road traffic accidents, has found that those given the smaller amount of alcohol experienced more flashbacks during the next week than those given the larger amount of alcohol, and those given no alcohol. Although that may seem to suggest drinking a large amount of alcohol might result in less involuntary re-experiencing of the event, excessive alcohol produced an overall reduction in memory which may be even more distressing if they then imagine a 'worse case scenario.' The findings support the view that flashbacks reflect the reactivation of image-based egocentric representations (based on sensory features) in the absence of a corresponding allocentric representing (incorporating the spatiotemporal context). Alcohol appears to impair allocentric (contextual) memory first.
Reference:
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(Submitted). Acute Effects of Alcohol on Intrusive Memory Development and Viewpoint Dependence in Spatial Memory Support a Dual Representation Model.
Biological Psychiatry. In Press, Corrected Proof,