Dopaminergic System and Apathy in Alzheimer's Disease

Apathy, or the loss of motivation, occurs in up to 80% of patients with Alzheimer’s disease (AD). With a loss of motivation, patients are unable to carry out basic everyday tasks by themselves. Hence, the patients rely more on their caregivers, increasing not only the burden, but also the stress level of the caregiver. The underlying cause of apathy in AD has not yet been clarified. In the brain, there is an important system that regulates motivation, known as the Brain Reward System. Studies have shown that when people stop using drugs of abuse that stimulates the Brain Reward System, apathy is one of the main symptoms they develop. Dr. Lanctôt has hypothesized that the apathy that develops in AD may be due to a loss of rewarding effects from the Brain Reward System. In this study, the rewarding effects will be measured following a single dose of a drug that stimulates the Brain Reward System (dextroamphetamine). This will determine first, if patients with apathy will respond differently than patients without apathy, and second if the results from the Brain Reward System probe can be used to predict whether or not AD patients with apathy improve when treated. This study has the potential to improve the treatment of an important symptom that has not been adequately studied or treated.