© 2002 Society for the Study of Addiction to Alcohol and Other Drugs Addiction, 97, 1219–1223 Blackwell Science, LtdOxford, UKADDAddiction0965-21402002 Society for the Study of Addiction to Alcohol and Other Drugs 97912191219Letter to the EditorLetters to the EditorLetters to the Editor Letters to the Editor IS EXTINCTION IN ANIMALS THE SAME AS ABSTINENCE IN HUMANS? Sir—Conklin & Tiffany (2002) describe elegantly how behavioral results from studies of non-humans can be useful in developing new cue-exposure treatments. At several points in their article they equate implicitly or explicitly extinction in studies of non-humans with absti- nence in drug abusers trying to stop. I believe the two are not equivalent (Hughes & Bickel 1997). The extinction procedure in non-humans involves typically either removing a lever used for drug self- administration or making lever presses no longer produce drug injections. Neither mimics the situation of a typical drug abuser trying to stop. Rather, the former is analo- gous to being in an in-patient ward and the latter to pay- ing for and receiving placebos. Most drug abusers initiate abstinence either because a real or implied punishment will occur with drug use or because strong non-drug reinforcers are made contingent on not using drug. To mimic the former, non-human researchers could either suppress drug self-administration by intermittent punish- ment or by a stimulus paired with punishment. To mimic the latter, they could make food or other strong reinforc- ers contingent on progressively longer periods of no drug self-administration. Conklin and Tiffany argue that context determines the function of conditioning stimuli. If so, then how a condi- tioned stimuli functions is likely to be different with removal of a lever or with non-productive lever-pressing than with suppressed responding due to punishment or non-drug reinforcers. I believe results from non-human studies using the latter two paradigms may better gener- alize to the human condition. Declaration of interests Since 1 January 2001, I have received honoraria, con- sulting fees or research grants from the following organi- zations that market tobacco cessation/prevention product/services/information or conduct tobacco-related litigation: Alden Corporation, Astra Pharmaceuticlas, American Council on Science and Health, American Society of Addiction Medicine, Canadian Society of Addiction Medicine, Edelman Public Relations, Glaxo- SmithKline Beecham Consumer Healthcare, Glaxo- Wellcome Pharmaceuticals, Healthwise, Krug Associ- ates, National Cancer Institute, National Institute on Drug Abuse, New England College Health Association, Palladin Associates, Pharmacia, Shook Hardy and Bacon, Society for Research on Nicotine and Tobacco, University Medical and Dental School of New Jersey, Walker Law Firm, Yale Medical School. JOHN R. HUGHES University of Vermont Departments of Psychiatry, Psychology and Family Practice 38 Fletcher Place Burlington, VT 05401-1419 USA E-mail: john.hughes@uvm.edu References Conklin, C. A. & Tiffany, S. T. (2002) Applying extinction research and theory to cue-exposure addiction treatments. Addiction, 97, 155–167. Hughes, J. R. & Bickel, W. K. (1997) Modeling drug dependence behaviors for animal and human studies. Pharmacology, Biochemistry and Behavior, 57, 413–417. 97912191221Letter to the EditorLetters to the EditorLetters to the Editor CUE-EXPOSURE TREATMENT: TIME FOR CHANGE Sir—We thank Drs Niaura, Drummond and Hughes (Drummond 2002; Hughes 2002; Niaura 2002) for their comments and appraisals of our manuscript, ‘Applying extinction research and theory to cue-exposure addiction treatments’ (Conklin & Tiffany 2002). Although we agree with many of their points, we wish to clarify our position and comment on where we disagree with certain of their conclusions and suggestions. In our paper, we reviewed the cue-exposure treat- ment literature and made recommendations for how extinction-based treatments might be enhanced through the application of contemporary animal research and models of learning. In order to establish the overall effi- cacy of this treatment, we conducted a meta-analytical review that revealed, much as many in the field would suspect, that it is not particularly effective in treating