Addiction

• Addiction

  Includes the ideas of withdrawal syndromes, tolerance and dependance (both physical and psychological)
• Withdrawal syndromes

  • Occur when the patient stops taking the addictive substance, or consumes a smaller dose, and experiences symptoms opposite to those induced by the drug
  • Often very unpleasant, such as severe insomnia and nausea
  • Addicts are motivated to continue carrying our addictive behaviours in order to avoid withdrawal symptoms and elongate the positive effects of the addiction
• Tolerance

  • Occurs when an increasingly high dosage of a drug does not produce the desired results or effects for the patient
  • Results in a spiral or cascade of usage, where increasingly larger doses are required
  • Particularly problematic in surgery, where alcohol or drug addicts need higher doses of anesthetic, due to a tolerance to sleep-inducing drugs
• Physical dependence


  Characterised by withdrawal symptoms subsiding when the drug has been administered to the patient, and shows that their body cannot function normally without the drug, thus causing physiological changes
• Psychological dependence

  Occurs when patients experience compulsions to acquire the drugs in order to experience the pleasurable effects once again, leading to the development of a habit due to this system of 'usage and reward'
• Genetic risk factors in the development of addiction

  • Individuals may inherit candidate genes which provide them with a heredity predisposition towards developing an addiction
  • Abnormally low levels of D2 receptors in the brain, meaning that fewer dopamine molecules can bind to these receptors and initiate action potentials in the postsynaptic membrane
  • Abnormal gene expression of the gene coding for the CYP2A6 enzyme, leading to slower rates of nicotine breakdown and reducing the concentration of nicotine metabolites within the brain's synapses
• Adoptees with at least one biological parent with an addiction, were at a 4.4% greater risk of developing an addiction, compared to adoptees with no biological predisposition
• Purely genetic factors, such as candidate genes, may not be the only genetic factors influencing the development of addictions
• Psychosocial risk factors in the development of addiction

  • Personality
  • Family influences
  • Peer influences
  • Stress
• Impulsivity

  Associated with irrational risk-taking behaviours and little reflection, and due to its high concordance rates with addiction, suggests that there may be common neurological bases for both
• Family influences

  • The extent to which the child's behaviour is being monitored (increased monitoring reduces the likelihood of addiction formation)
  • The child's perception of their parent's attitudes towards addictive substances
  • A child's degree of exposure to such substances
• Peer influences

  Peers provide opportunities for regular access to addictive substances, and their use informs observers of 'norms' of consumption, which they often aim to exceed due to their incorrect perceptions
• Stress

  Chronic stress acts as a predisposition towards stress (a diathesis) which then must be paired with an environmental stressor (e.g. childhood rape) to result in addiction
• No one factor has been found to be more important than another in determining the likelihood of developing an addiction, but rather the combinations of different factors help to inform us of the severity and type of addiction which may be caused
• Correlational studies suffer from the 'third factor' problem and the file drawer problem, meaning they can never establish a cause and effect relationship between two factors
• An improved understanding of the various risk factors and the extent to which they interact can be useful for social services for identifying families at risk of their children developing addictions, as well as creating interventions for adolescents
• Desensitisation hypothesis

  There is an antagonistic effect between the levels of acetylcholine and dopamine, particularly in the areas of the brain which control feelings of pleasure and pain, such as the ventral striatum and the nucleus accumbens

  
• Nicotinic receptor desensitisation

  1. Nicotinic receptors allow both acetylocholine and nicotine to bind, generating an action potential

  2. The presence of nicotine causes the receptors to undergo deregulation/desensitisation, becoming less sensitive and reducing neurotransmission

  3. This leads to feelings of heightened pleasure due to the release of dopamine in the mesolimbic system

  
• Nicotinic receptor upregulation (withdrawal)

  1. Decreased nicotine levels causes the nicotinic receptors to become sensitive again to acetylcholine, leading to an increased rate of action potential generation within the nucleus accumbens

  2. This results in feelings of anxiety and potentially nausea

  3. The only way to relieve these feelings is to increase nicotine consumption again to provoke deregulation
• Tolerance

  Over time, the concentration of nicotine required to provoke deregulation increases periodically
• Patients taking the dopamine antagonist Haloperidol smoked significantly more than those who were not taking the drug, suggesting a higher consumption of nicotine was needed to maintain the deregulation of nicotinic receptors
• There has been too much emphasis on the role of dopamine in the maintenance of nicotine addictions, and that there is not one isolated system or neurotransmitter which is solely responsible

  
• An interactionist approach may be a better explanation for nicotine addiction, whilst acknowledging the role of biological factors
• Social learning theory

  Nicotine addictions can be acquired through both classical and operant conditioning
• Positive reinforcement

  Smoking can be positively reinforced by the reward of the euphoric feelings of nicotine stimulating the dopaminergic mesolimbic system
• Negative reinforcement

  Smoking can be negatively reinforced by avoiding unpleasant withdrawal symptoms, through progressively increasing nicotine intake and therefore prolonging the period of desensitisation or deregulation of nicotinic receptors in the nucleus accumbens
• Cue reactivity

  • There are certain environmental cues, such as attending parties or social gatherings, which increase the likelihood of engaging in addictive behaviours, such as smoking
  • These environments contain both primary reinforcers (the pleasurable effects of smoking) and secondary reinforcers which coincide with the benefits of smoking (such as the smell of cigars, the cardboard feel of the packet and the neat arrangement of cigarettes)
  • Primary and secondary reinforcers work together, through the process of cue reactivity (made up of behavioural responses, physiological responses and our own personal attitudes towards smoking) to reinforce and maintain excessive smoking habits
• Women are less likely to give up smoking and more likely to relapse, which may be due to their poor self-efficacy and their increased sensitivity to cues which trigger smoking due to being more socially engaged
• Rats rapidly increased their intravenous intake of nicotine periodically, resulting in up to 100 licks/ attempts per infusion, supporting the role of cue reactivity and positive reinforcement in the development of nicotine addictions
• Aversion therapy using electric shocks produced nicotine addiction recovery rates that were at least 32% higher compared to people who had simply decided to stop smoking, demonstrating the real-life applications of learning theory as an explanation for nicotine addiction
• Nicotine administration

  May be the result of pleasurable effects associated with increased dopaminergic stimulation of the mesolimbic system and the deregulation of nicotinic receptors
• Learning theory

  Useful real-life applications because aversion therapy and covert sensitisation is based upon these same principles
• Smith (1988) found that aversion therapy using electric shocks produced nicotine addiction recovery rates that were at least 32% higher compared to people who had simply decided to stop smoking
• An improved understanding of learning theory as an explanation for nicotine addiction may serve as an economical implication of psychological research, where improved NHS and public health service guidelines for the treatment of such a common addiction could be beneficial for sufferers
• Gambling addictions

  Can also be explained using social learning theory, with specific emphasis being placed on cue reactivity and five types of reinforcement (positive, negative, variable, partial and vicarious)
• All types of reinforcement increase the likelihood that the specific behaviour will be displayed again
• Cue reactivity

  Serves as the main explanation for the particularly high relapse rates associated with gambling addictions
• Low-level cues which continuously provoke sufferers to further engage with gambling activity


  • Presence of gambling shops on many high street
  • Glamorous TV reports of the latest lottery winners
  • Discounted entry for various gambling websites
• Partial reinforcement

  Behaviours most resistant to extinction are not produced through the consistent rewarding of desirable behaviours. Instead, the occasional winning bet experienced by gamblers is almost as rewarding compared to winning each time, due to the anticipation
• Variable reinforcement

  A gambler has a certain statistical chance of winning e.g. an average of 20 throws of the dice. However, this does not necessarily mean that every 20th throw will result in winning a reward, and so they are motivated by this continuous temptation and 'statistical justification' to continue betting