To the Editor.—
Gawin and Kleber1 have made an important contribution by focusing attention on the symptoms associated with cessation of cocaine use. They attempt to categorize the period of abstinence into three phases, which they termed the crash, withdrawal, and extinction phases. While noting that other authors have described and identified the crash phase as withdrawal, the authors go on to make a distinction between their crash (or first) phase, when the user becomes more interested in sleep than in obtaining cocaine, and their withdrawal (second) phase, when sleep has normalized and craving for cocaine reemerges. Gawin and Kleber stress the clinical importance of this withdrawal phase because it corresponds to a period of maximal relapse potential.We believe that this conceptualization of cocaine abstinence into three phases may require revision for several reasons. First, a number of methodologic problems limit the reliability and validity of the data.