—Dackis1 and we2,3 have previously noted clinical impressions like those that we systematically observed in our sample of 30 cocaine abusers. The same impressions were first described by Lewin 99 years ago and elaborated by Maier over 50 years ago.4 Connell and Ellinwood have described similar impressions in chronic amphetamine abuse. However, no previous reports of cocaine or amphetamine abuse reports fully elaborated the nature or importance of phase 2 symptoms.
Our article's4 clinical focus did not warrant detailed discussion of neurophysiology, so the comments of Dackis et al provide a welcome opportunity to clarify current issues and hypotheses. The importance of dopamine in stimulant euphoria and addiction was first established for amphetamine in the early 1970s in a series of studies by Wise and coworkers, as well as several other groups.5 This was also substantiated for cocaine by DeWit and Wise in 1977.