Week 2 - Review of Neurobiology Flashcards
What are the Drug Use Models?
- Disease model
- Physical dependence Model
- Positive reinforcement model
What is the disease models definition of addictive behaviour?
• Compulsive (impaired control over use of the drug) & self-destructive (harmful consequences to user)
What are the related theories of the disease model?
Predisposition and exposure theories
What are the strengths of the disease model?
- May make accessing treatment easier
- Rules that usually govern behavior may not apply to drug taking, since this behavior is abnormal
- Can account for individual differences in response to drugs
What are the limitations of the disease model?
- “What is the disease?” (by, to what extent do we need to be able to identify the disease?)
- May reduce individual responsibility for behavior
What factors does the disease model not consider?
x. Related to socioeconomic factors – increase in opium use when socially acceptable
x. Addiction follows the same pattern as epidemic (growth and lessening, isolated to areas ect)
x. Other factors other than just the drop – also the do with socioeconomic, culture ect
What is the Physical Dependence Model?
“The state in which the discontinuation or reduction of a drug would cause withdrawal symptoms”
What are withdrawal effects?
• Repeated drug administration body learns to adjust to drug-induced changes
• Drug removed body readjusts again (withdrawal)
• Withdrawal symptoms: usually opposite symptoms incurred by drug
• > Can be stopped by re-administering the drug, or a similar drug (cross-dependence)
o Drug may be re-administered to counteract withdrawal effects
What doesn’t the PDM account for?
relapse that happens after the withdrawal effects are over
What are the strengths of the Physical Dependence Model?
o Compatible with disease model; plausible explanation for addiction to drugs with withdrawal effects
What are the limitations of the Physical Dependence Model?
o Individual differences as well as the disease model can;
o Substances of addiction that show little to no withdrawal sickness;
o Voluntary withdrawal (despite symptoms)
• Attempts to refine model: psychological dependence
o Circular reasoning
o Difficult to assess outward manifestations
What is the Positive Reinforcement Model?
• Drugs are self-administered because they act as positive reinforcers (operant conditioning)
What is a positive reinforcer?
“any stimulus that increases the frequency of a behavior it is contingent on”
What are two things that support the positive reinforcement model?
• Drugs that are self-administered by animals even in the absence of physical dependence/withdrawal
o (Intragastric, intracranial, intraventricular, inhalation & oral routes)
• How the drug is administered has a large impact on how addictive it can be
o E.g. smoke is taken up by body much faster than those taken through the digestive system (e.g. crack cocaine much more addictive as it can be smoked/ opium ect)
What are the limitaitons of the positive reinforcement model?
o Can the positive consequences of behavior outweigh the costs (positive reinforcement paradox)?
o Circularity: drug is +ve reinforcer bcs increased drug taking behavior; then positive reinforcement cannot explain drug taking
What are the strengths of the positive reinforcement model?
o Accounts for drug-taking behavior in absence of dependence/withdrawal;
o Compatible with disease/physical dependence model;
o Compatible with general models of reinforcement
How does classical and operant conditioning apply to drug taking?
- Reinforcing effects of drugs can be paired with other stimuli through conditioning
- An extinction phase can be demonstrated
- Responses to operant reinforcement schedules can be elicited as predicted
- Responses can be elicited following priming
- Response patterns to substances that act as aversive stimuli are consistent with avoidance behaviours
- A conditioned compensatory response can be demonstrated
How does positive reinforcement relate to neurobiology?
• Positive reinforcers activate motivational circuits
o May increase likelihood of behavior repeating
• Pleasure centers/motivational circuit (neuroanatomy)
• Motivational circuit relies on activity of neurotransmitters (NTs)
• Incentive salience (natural and acquired)
