is a neurological phenomenon associated with increased confusion and restlessness in patients with delirium or some form of dementia.Most commonly associated with Alzheimer's disease, but also found in those with other forms of dementia, the term "sundowning" was coined due to the timing of the patient's confusion.
They were also with ex-Formula One boss Paddy Mc Nally, 77, who used to date Prince Andrew’s former flame Sarah Ferguson.
In individuals with dementia, melatonin production may be decreased, which may interrupt other neurotransmitter systems.
Sundowning should be distinguished from delirium, and should be presumed to be delirium when it appears as a new behavioral pattern until a causal link between sunset and behavioral disturbance is established.
While the specific causes of sundowning have not been empirically proven, some evidence suggests that circadian rhythm disruption increases sundowning behaviors.
In humans, sunset triggers a biochemical cascade that involves a reduction of dopamine levels and a shift towards melatonin production as the body prepares for sleep.