Abstract
• The Cross-National Collaborative Panic Study is a two-phase multinational, multicenter controlled trial for the evaluation of drug treatment of panic disorder and associated agoraphobia. The First Phase compared alprazolam with placebo in a large sample of more than 600 subjects at eight centers—five in the United States, two in Canada, and one in Australia. the Second Phase compared alprazolam, imipramini hydrochioride, placebo in more than 1100 patients in 14 countries. The scientific background, aims and purposes, governance, and policies regarding statistical analyses and scientific presentations and publications are reviewed as background for the series of individual articles reporting detailed findings from the First Phase.