Final answer:
Chronic alcohol use is a specific risk factor for developing delirium, as it can cause neurological changes and deficiencies that predispose individuals to this condition.
Step-by-step explanation:
The risk factor believed to be specific to the development of delirium is chronic alcohol use. Delirium is an acute disturbance in attention and cognition, and it can be induced by a variety of factors in individuals, especially in elderly patients. Factors that can contribute to the development of delirium include advanced age, pre-existing cognitive impairment, severe illness, medications, and substance abuse, such as with alcohol. Chronic alcohol use can lead to neurological changes, vitamin deficiencies, and liver damage, all of which may predispose an individual to delirium.