HTR1A and delirium: One of the very few published animal studies in delirium gives support to our finding; in a rat model delirium was associated with increased CSF levels of the serotonine metabolite 5-HIAA and the dopamine metabolites HVA and 3,4-dihydroxyphenylacetic acid, and treatment with a selective serotonin 5HT1A antagonist reduced delirium symptoms in the same animals [29].