The drugs now available to treat the memory and thinking problems of Alzheimer's disease have not lived up to the public's high expectations for them and offer such modest benefits on average that many doctors are unsure about whether to prescribe them. Although the drugs have their advocates, grateful for any sign of improvement, others express disappointment in light of earlier hopes that the drugs approved in the last decade would stop the disease or markedly slow it. At a meeting in late March at Johns Hopkins University, doctors and other health professionals heard Alzheimer's researchers debate the usefulness of...