ObjectiveDelirium in critically ill patients is considered a risk factor for various long-term consequences. We evaluated delirium and associated long-term outcomes in patients with acute respiratory distress syndrome with non-H1N1 and H1N1- associated severe community-acquired pneumonia (sCAP) who had been recommended to take antiviral drugs associated with delirious symptoms as adverse effects.MethodsOf 64 patients, 42 survivors (H1N1, 15; non-H1N1, 27) were analyzed regarding the relationship between medication and the duration of delirium in the intensive care unit. During follow-up (n = 23), we assessed cognitive abilities, post-traumatic stress disorder (PTSD), physical capacity, and health-related quality of life (HRQoL).ResultsThe incidence of delirium was 88%. There was no difference in the incidence and duration of delirium between patients with H1N1 and non-H1N1 infection. The haloperidol and opioid doses were associated with a longer delirium duration. The delirium duration was correlated with reduced cognitive performance in motor skills, memory function, and learning efficiency. Patients with PTSD (16%) had a significantly longer delirium duration and low mental HRQoL.ConclusionsH1N1 infection and corresponding antiviral medication had no impact on delirium. The duration of delirium in these patients was associated with impairments in various outcome parameters, illustrating the burden of sCAP.