Abstract
Background: Delirium is a common and serious acute condition in the elderly, characterized by changes in cognition and alertness, and is associated with poor outcome with an increase in mortality, impaired physical and cognitive recovery. Despite this, little is known about the pathophysiology of delirium. The last years there has been a rapid growth on studies published on delirium. We therefor aimed to do an updated systematic search for studies exploring the association between delirium and genetics. Methods: We systematically searched in the databases Medline PsycINFO and Embase for articles concerning genetic associations and the occurrence and outcome of delirium. There were no limitations in year published. A total of 465 articles was found, and 21 articles were included. Reviews, conference abstracts, leaders and articles about alcohol withdrawal delirium were excluded. Results: Of 21 included articles, 13 looked at the association between carriers of the APOE-4 allele and delirium. The results differ, 4 of the articles found an association, and the rest did not. Two of them showed an increased incidence, one showed a longer duration of delirium, and the last one showed an association with greater delirium severity. On the other hand, two meta-analysis did not show any association. Other genes that were found to have an association to delirium was NMDA-3A-receptor and glucocorticoid receptor which showed an increased incidence of delirium, and dopamine-D2-receptor and a dopamine transporter SLCA6A which showed a decreased incidence. Conclusion: Results are inconclusive, but these findings suggest that APOE-4 is not an important risk factor for developing delirium. Disturbance in neurotransmitters in the brain may be a part of the pathophysiology, and mine findings support the association between delirium and dopamine and glutamate, while serotonin is less likely. Disturbance in cortisol may also play a part in the pathophysiology. More research is necessary to confirm these findings