Factors of Development of Drug Dependence

Question 1

Reinforcing Effects of Drugs:

Answer 1

• Positive reinforcement via elevation of mood, euphoria from ecstasy, cocaine, opiates…etc
• Positive reinforcement via functional enhancement from nicotine and caffeine (i.e. enhances alertness, attention…etc)
• Negative reinforcement via relief from anxiety, pain, and withdrawal symptoms
Specific effects differ depending on specific drugs

Question 2

Stimuli Conditioned to Drug Effects:

Answer 2

• Contextual stimuli previously associated with drug taking
• Subsequent exposure to stimuli can produce drug-like (primers) or drug opposite (withdrawal) effects
• Primers remind you how good the drug feels, induces cravings
• Withdrawals produce withdrawal effects,
Demonstrates Pavolvian conditioning

Question 3

Discriminative Subjective Effects:

Answer 3

• Drugs produce subjective internal states that can act as cues to control behaviour
• Experienced users come to expect these effects
Expectations contribute to drug seeking and drug using

Question 4

Aversive Effects of Drugs:

Answer 4

• Decreases likelihood of using drugs
• Some drugs can produce aversive effects (i.e. cocaine causes anxiety after euphoria)
When not self administered, some drugs of abuse are aversive (need to be in control)

Question 5

Yoked Control Procedure:

Answer 5

Rats will self administer nicotine, but will learn to press a lever to avoid experimenter controlled injections of same drug

Question 6

Risk Factors

Answer 6

• Psychological/ personality- ability to cope with stress, depression, aggressiveness..etc
○ High correlation of personality/mood disorders with drug abuse/dependence
• Family- modeling plays a role in likelihood of using drugs
• Sociocultural
○ Social facilitation (not comfortable in social situations without drugs)
○ Escape mechanism (escaping stress via drugs)
• Genetic
Sensitivity of neurotransmitter receptors, enzymes…etc

Question 7

Protective Factors:

Answer 7

• Decreases likelihood of using drugs
• Absence of risk factors
○ Stable family, no genetic predisposition, no risky personality traits/disorders
• Can maintain stable abstinence in previously addicted or abusing individuals
i.e. marriage, moving…etc can help avoid drug associated cues or provide new sources of reinforcement

Question 8

Evidence for Addiction Like Behaviour in Rats:

Answer 8

• Rats self administered cocaine via nose poke over the course of 3 months
• Probe sessions- measured drug seeking activity, but conditions changed slightly
• Difficulty stopping drug use even when nose poke was not followed by cocaine
• Continued use of substance even when delivery of drug was associated with punishment (shock)
High motivation to take drug- progressive ratio schedule used (increased number of responses needed to get drug), high breaking point (max amount of work animal will perform before ceasing to respond)

Question 9

Vulnerability to Relapse:

Answer 9

• 5 days of abstinence (withdrawal) at the end of the experiment
• Gave rats tiny dose of drug (priming)
• Rats susceptible to relapse were the same rats that displayed high levels of responding even when drug not delivered, drug was paired with pain, and had a high breaking point
• Rats susceptible to relapse did not display these characteristics during the experiment
• Rats that met all 3 criteria also displayed each of the 3 characteristics very strongly
• 17% met all three criteria
• Control
○ Rats that met 0 criteria and rats that met 3 criteria allowed to self administer cocaine, both groups self administered the same amount of cocaine
○ Rats given cocaine and measure activity levels using a photocell cage (lazer beam maze, measured number of breaks) to see if sensitivity to drug changed, it didn’t
○ No pre exisiting differences between animals or amount of cocaine they received
• Therefore, addiction like behaviour= intensity of drug exposure + individual variability