Learning and Addiction

Learning and Addiction

1. Predictors of Addiction

   • Genetics (50%)
   • Environment
   • Stage of Life
   • Temprement
     • Impulsivity
       • Pre-dates drug use Ersche, and colleagues (2010) compared substance-dependent individuals with their siblings
       • Impulsivity did not make any difference to the propensity to administer cocaine. High imulsive rats is a predictor of an addiction like pattern of drug useBelin, Mar, Dalley, Robbins and Everitt (2009) compared rats that were either high or low in impulsivity and rats that were high and low in responding to novelty 
       • -negatively correlated with midbrain dopamine receptors
       • -positively correlated with release of dopamine
     • Sensation - Seeking
       • Sensation-seeking may be a cause of drug use Ersche, and colleagues (2010) compared substance-dependent individuals with their siblings
       • sensation seeking and not impulsivity seems to be associated with initiation of drug use Belin, Mar, Dalley, Robbins and Everitt (2009) compared rats that were either high or low in impulsivity and rats that were high and low in responding to novelty

2. Incidence of addiction

   • 32% tobacco, 23% heroin, 17% cocaine, 15% alcohol, 9% marijuana

3. Drugs of abuse increase Dopamine reward

4. Drug tolerance - decrease effectiveness

   • More like habituation (not adaptation)
     • Opponent Process Theory can explain drug tolerance through habituation of the initial pleasurable response to the drug and the growth of the opponent negative reaction to the drug which occurs with repeated drug use
     • Drug-like : cravings cause a desire to have the drug due to an expectancy or memory
   • Conditioning: CS (related cues) > US (drug) > UR (drug effects)
     • cues which are associated with drug administration such as the context in which the drug is usually given and the injection procedure itself, result in a both an expectancy for the positive aspects of the drug as well as a reflexive compensatory response to the physiological disturbance of the drug. Thus, when the drug is administered the compensatory conditioned response reduces the physiological disturbance produced by the drug which results in drug tolerance
     • Drug Opposite: withdrawal produces effects such as negative mood state, irritability, nausea, diarrhoea, insomnia, and loss of appetite depending on the drug
       • Shep Siegel's rat experiment tested whether drug tolerance is influenced by the association between the drug and specific environmental cues, and his findings suggested that conditioning might be a contributing factor in drug tolerance
       • Overdose: A critical factor seems to be the setting within which the drug is administered. •An addict’s tolerance to heroin is much greater in the presence of drug associated cues.

5. Treatment

   • Stimulus Control
     • Elimination of cues and situations that were previously precursors of drug use.
   • Extinction
     • Exposure to drug associated cues in the absence of drug use or the effects of drug use
     • Behavioural treatments less effective
   • Counterconditioning eg graphic images
     • Exposure to the taste or alcohol or cigarettes followed by a drug that produces nausea and vomiting
     • Abstinis drops off
   • Competing Response Training
     • Perform behaviours that are incompatible with drug use whenever drug CSs are encountered.
   • Drug Replacement Therapies
     • Can help to break the contingency between the drug associated cues and the delivery of the drug
   • Contingency management
     • Uses an instrumental conditioning procedure (token). •Patients are rewarded for negative drug tests. •The most effective available treatment for addiction but not widely used. 

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