Lecture 3 - Theories of addiction, the role of DA, polydrug use and behavioural addictions

Question 1

How has addiction been explained in psychological and psychobiological terms?

Answer 1

• Psychobiological factors
• Learning model
• Social factors and brain plasticity
• Dopamine hypothesis
• Incentive Sensitisation Theory

Question 2

Study: Brewer & Potenza (2008); Prescott & Kendler (1999)

Answer 2

Twin studies - comparing MZ and DZ twins suggests 50% of variation in risk of becoming addicted predicted by genetics

Question 3

How can the Learning Theory be used to explain addiction?

Answer 3

• Behaviour occurs in relation to reinforcement and punishment resulting from that behaviour
• Certain antecedents may make sensitisation to reinforcement from substances more likely such as trauma or genetics
• Reinforced behaviours repeated/increased and punished behaviours ceased/decreased

Question 4

How can positive reinforcement be used to explain drug addiction?

Answer 4

• drug using behaviour is positively reinforced (especially in early episodes)
• Effects of drug are often very positively reinforcing
• ‘Liking’ stage as opposed to ‘wanting’
• Other reinforcement comes from social acceptance/bonding

Question 5

How does positive reinforcement occur as a result of the DA pathways in the brain?

Answer 5

• Drugs release DA in mesolimbic and mesocortical DA pathways ascending from the VTA
• Nucleus accumbens plays an important role
• Induces human/animal to seek and consume drugs
• Animals work hard for drug reward - especially for psychostimulants
• Cues associated with drugs trigger drug-seeking in humans and animals

Question 6

How can negative reinforcement be used to explain drug addiction?

Answer 6

• Use of drug removes unpleasant stimulus/discomfort
• Substances might be used to reduce pain or psychological discomfort, e.g., from trauma, anxiety, depression
• With repeated use, removal of withdrawal can be a motivation

Question 7

How can classical conditioning be used to explain drug addiction?

Answer 7

• Drug-related stimuli can induce craving, changes in autonomic responding and alterations in drug-seeking behaviour
• Environmental contexts or drug paraphernalia can cause these reactions
• These become CS due to repeated pairing with drug (US) and thus elicit similar responses (CR)
• Brain expects drug and thus begins process of compensatory responses in anticipation which feels like withdrawal

Question 8

What is situation-specific tolerance?

Answer 8

Cues in environment become associated with drug use
- Places
- People
- Objects
etc.

Question 9

What is conditioned Place Preference?

Answer 9

• Specific place is initially neutral stimulus
• With repeated administration of a drug in the same area of the environment it becomes CS
• Preference measures in terms of the amount of time the person/animal spends in this environment compared to another
• Environment (CS) takes on properties of US and can elicit conditioned drug responses

Question 10

Cue exposure therapy - addiction therapy based on classical conditioning

Answer 10

• Aims to reduce conditioned drug effects
• Based on the principle of extinction - repeated, non-reinforced exposure to drug cues diminishes conditioned drug effects
• However, outcome data from studies are inconclusive
• Likely that many other processes are involved

Question 11

What are social factors of drug addiction?

Answer 11

• Certain environmental and interpersonal conditions of upbringing can predict greater likelihood of problematic drug use
• Early trauma reliably correlated with greater risk of problematic substance use and addictive behaviours