Abstract: Based on analysis and coding of the depth interviewed materials from 78 drug addicts and their family members, the authors found an extremely common phenomenon: whenever drug addicts returned to a previous space where they used drug, they were attacked by the symptoms of drug withdrawal. This phenomenon couldnt be explained effectively with such learning theories as Pavlovs classical conditioning, Skinners operant conditioning or Banduras social cognitive theory, which are considered as canonical theories in the psychological textbooks. Accordingly, the authors formulated Type D conditioning hypothesis and investigated five related themes: (1) defining the concept of drug; (2) three phases of Type D conditioning; (3) fundamental differences between Type D conditioning and classical conditioning; (4) from Type D conditioning to operant conditioning; (5) the prospects and practical implications of researches into Type D conditioning. Type D conditioning hypothesis is innovation for learning theories of classical conditioning, operant conditioning and social cognitive theory. Moreover, Type D conditioning hypothesis stands for innovation of the 20th century Western psychology by the 21st Chinese psychology. On the perspective of behaviorist psychology for drug control, Type D conditioning hypothesis is innovation of antidrug psychology.

Key words: drug addicts; classical conditioning; operant conditioning; social cognitive theory; Type D conditioning; nonextinction