A nurse is admitting a client to the hospital unit. Which one of the following elements of the client's history and physical assessment increases the risk for the development of delirium?

Choice A reason: A history of lymphoma alone does not directly increase the risk of delirium unless associated with acute illness, infection, or treatment-related complications. Choice B reason: Sex is not a primary risk factor for delirium. Delirium risk is more strongly associated with age, substance use, acute illness, and medication effects. Choice C reason: Lack of medical insurance is a social stressor but does not directly contribute to the development of delirium. Choice D reason: A history of drug and alcohol use significantly increases the risk for delirium due to potential withdrawal states, intoxication, and altered neurotransmitter activity. Substance-related factors are well-recognized contributors to acute confusional states.