Today, there is no high-level evidence for any effective treatment of apathy in AD. In contrast to other neuropsychiatric syndromes in AD, like psychosis and depression, and despite its high prevalence and clinical relevance, apathy has never been the primary outcome in a clinical trial. Basic and clinical research has provided a distinct model of the pathophysiology of apathy with dopamine and norepinephrine as the key neurotransmitter systems involved. The antidepressant Bupropion is a dopamine and norepinephrine reuptake inhibitor. There is evidence from case-series, that Bupropion reduces apathy in patients with organic brain disorders. This study will test the efficacy and safety of Bupropion in the treatment of apathy in AD in a 12-week multicenter doubleblind placebo controlled trial. Secondary endpoints will be quality of life of patients, caregivers' distress, ability of patients to perform activities of daily living,utilization of healthcare resources by patients and by caregivers, and cognitive functions.