A conference was held in Brussels in November 1997 under the auspices of the International Working Group for Harmonization of Dementia Drug Guidelines. The meeting reviewed development of European Dementia Guidelines, with a focus on the roles of academics, industry, the European Commission, the European Parliament, and the European Medicines Evaluation Agency. The objectives of the meeting were to review progress in development of dementia drug guidelines across Europe, with particular reference to harmonization of these efforts with developments in other countries, particularly the United States and Japan. Specific topics covered included issues in developing trials to address disease progression, very mild disease, severe disease, and the non-Alzheimer dementias. Clinical trial designs and the types of measures chosen in these new areas are unlikely to be the same as those used in previous trials for symptomatic relief of mild-to-moderate Alzheimer disease. The assessment tools need to be specific for the purpose of the trial and ongoing research is still needed in this area. Little is known about the natural progression of disease based on the types of measures used in clinical trials. Evidence suggests that rates of decline are variable and nonlinear. Improved collaboration between academics, industry personnel, and regulators, particularly through the sharing of placebo data sets, could allow considerable advances in our understanding of natural disease progression.