[Delirium is a very common and life-threatening condition].

Although a lot is known regarding the epidemiology and aetiology of this condition, the pathophysiology of delirium remains poorly understood. Today, the leading hypothesized mechanism for the pathogenesis of delirium focuses on a central cholinergic deficiency and dopamine excess. Besides, other neurotransmitters, such as dopamine, serotonin, norepinephrine, glutamate and gamma-aminobutyric acid (GABA) may also contribute to delirium. Moreover, cytokines including interleukin-1, interleukin-2, interleukin-6, interferon and tumour necrosis factor alpha (TNF-alpha) can lead to an imbalance among the different neurotransmitters and thereby lead to an activation of the hypothalamic-pituitary-adrenocortical axis (HPA axis). The article reviews the current pathophysiological findings that may underly delirious states.