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PSYCHIATRIKI 21 (4), 2010 Cognitive theories of addiction: a narrative review 319Identity shift theoryA recently proposed theory explores loss of controlover rewarding behaviour from a different perspective.It is argued that what appears to be lack ofcontrol over substance use behaviour is in reality amanifestation of a fundamental feature of humanmotivation, the instability of preferences. In otherwords, addicted people change their minds dependingon internal and external circumstances. 19 Basedon the same principles, Identity Shift theory 20 takesinto account the principle of unstable preferencesand proposes that increasing distress caused by behavioursresults to value conflict. This prompts to asmall step towards behaviour change, which if successfulbegins to lead to an identity shift. Increasedself-awareness and self-confidence then fuel continuedchange. At the core of the model is the ongoingevaluation of benefits and costs and the build-upof dissatisfaction with the current situation. Then atrigger, small or major, results in an immediate andunplanned step of change that initiates the processof behaviour change.Expectancy theoryExpectancy theory was first proposed as a theoryof human motivation relating to work and jobsatisfaction. 21 The theory proposes that behaviorresults from conscious choices among alternativeswhose purpose is to maximize pleasure and minimizepain. The theory proposed that the ‘force’with which the individual will pursue his work isthe product of two sets of beliefs: valence and expectancy.Valence refers to the emotional orientationspeople hold with respect to rewards (extrinsic,such as money, promotion, time-off and benefitsor intrinsic, such as satisfaction). Expectancyrefers to the momentary belief concerning thelikelihood that a particular act will be followed bya particular outcome. 21 Employee’s performance isrelated to instrumentality. Instrumentality refersto the perception of employees whether they willactually get what they desire even if it has beenpromised by a manager. Performance is the productof employee’s force and his/her ability to executethe required action. The author commentsthat ability is a complex concept that involvesemployee’s actual skills and confidence. Severalhypotheses were generated from the theory andwere tested.According to expectancy theory and its applicationto addiction, expectancies about the costs orbenefits of drug use contribute to excessive use.These expectancies may involve more than beliefs(memory templates). The two main factors hypothesisedthat determine the initiation and repetitionof a specific behaviour by a human being are: theoutcome expectancy and the efficacy expectancy.22 The outcome expectancy is the belief that aspecific outcome (positive or negative) will occurfollowing certain behaviour, i.e. by following a certainroute you arrive on time at work. The efficacyexpectation is the belief that someone is able to executethe above behaviour, i.e. that you will be ableto drive on a motorway. Outcome expectancies arebuilt on previous experiences and maintained bypositive and negative reinforcements (social learningprocess).Other cognitive theoriesExpectancy theory places emphasis on consciouscognitive processes, which are related to the experienceof craving. Evidence though suggest thatsubjective report of craving is only moderatelylinked with substance use and relapse. 5 The cognitiveprocessing model proposes that drug abusecan operate independently of the processes controllingcraving. 23 According to this model, addictivedrug abuse is regulated by automatic cognitiveprocesses, while craving represents the activationof non-automatic processes. These non-automaticprocesses are activated to either aid in completinginterrupted drug use or block automatic drug-usesequences. 5Another cognitive model proposed that as addictiondevelops the expectancy-based control systemof behaviour becomes unconscious and thereforebehaviour is influenced less by conscious expectanciesinvolving controlled processes and more byunconscious expectancies involving automatic processes.24A recent extension of the expectancy theory is theCognitive Bias theory that aims to address shortfallsof earlier expectancy based cognitive models. 25