Cognitive Functions, Attention-Deficit Hyperactivity Disorders, and Alzheimer’s Disease

Attention-deficit (AD) hyperactivity disorder and Alzheimer’s disease are debilitating neurological disorders that affect patients at both ends of the age spectrum. The histaminergic system in the central nervous system is implicated in the control of wakefulness, and strong preclinical evidence suggests that blockade of histamine H₃ receptors can increase wakefulness, decrease impulsivity, and improve attention as well as other cognitive domains. Attentional deficits are observed as increased percentage of errors in operant tasks, whereas impulsivity is observed as the inability of spontaneous hypertensive rats to delay a response to obtain a larger reward. The unmet need in AD treatment extends beyond drugs that provide greater symptomatic relief with fewer side effects, to treatments that will ultimately slow, halt, or reverse the progression of the disease. AD, the most common form of dementia, is a progressive and devastating illness that robs the affected individual of the ability to learn, reason, remember events, and ultimately communicate and perform daily activities.