Week 4: Addictive Behaviours

Question 1

Why is addiction much more than dependence?

Answer 1

The word dependence has many meanings: some that don’t fit the criteria for addiction

Any drug can produce dependence if it is defined as the manifestation of a withdrawal symptom upon cessation of drug use Eg. Patient with terminal illness suffering from chronic pain and treated with morphine. May experience withdrawal symptoms but don’t actively engage in drug seeking behaviour

Question 2

What is addiction?

Answer 2

A recurrent pattern of maladaptive behaviour that includes drug seeking despite negative consequences and very often, relapse

Question 3

What is used instead of the word addiction in the DSM 5?

Answer 3

Substance use disorders.

Question 4

How many classes of drugs are listed in the DSM5

Answer 4

10. Alcohol, caffeine, cannibals, hullucinogens, inhalants, opioids, sedatives, hypnotics, stimulants, Tobacco or any other unknown substance

Question 5

How many criteria span substance use disorders?

Answer 5

11. But not all need to be met

2/3 = mild 
4/5= moderate 
6+ = severe

Question 6

What are the 3 characteristics of drug addiction

Answer 6

Compulsion to seek and take the drug

Loss of control in limiting intake

Emergence of a negative emotional state (dysphoria, anxiety, irritability) when access is prevented

Question 7

What are the two main components of drug addiction

Answer 7

Impulsivity and compulsion

Question 8

Explain drug addiction and impulsivity?

Answer 8

Impulse control disorders are characterised by an increasing sense of tension or arousal before committing an impulsive act there is pleasure, gratification or relief at the time of committing the act and there may or may not be regret or guilt following.

Question 9

Explain compulsion in relation to drug addiction

Answer 9

Compulsive behaviours are characterised by anxiety or stress followed by a compulsive repetitive behaviour and relief from the stress by performing the behaviour

Question 10

Explain positive and negative reinforcement in relation to impulsivity and compulsion

Answer 10

The search for positive reinforcement such as pleasure or gratification is more closely associated with impulse control where is negative reinforcement such as the relief of anxiety or stress is more closely associated with compulsive disorder

Question 11

Explain the transition from impulse to compulsion

Answer 11

As an individual translates from an impulsive disorder to a compulsive disorder there is a shift from positive reinforcement driving the motivated behaviour to negative reinforcement driving it

Positive experiences initially but as use of drugs becomes more chronic the negative reinforcement dominates behaviour to alleviate negative symptoms

These people become less driven by positive consequences of drug use and Morceau concerned with alleviation of negative symptoms

Question 12

Explain incentive sensitisation theory of addiction

Answer 12

Often when a drug is administered repeatedly its effects will not remain the same

Tolerance - decrease in the effectiveness of a drug that is administered repeatedly

Sensitisation - increase in the effectiveness of a drug that is administered repeatedly

When first used a drug produces a moderate amount of wanting and liking
With repeated use tolerance for wanting develops and liking decreases at the same time as the system that mediates wanting becomes sensitised and so wanting the drug increases

Question 13

Explain the dose-response curve

Answer 13

Drug tolerance is a shift in the dose response curve to the right therefore in tolerant individuals the same dose has less affect and a greater dose is required to produce the same affect

Question 14

Explain allostasis and negative reinforcement

Answer 14

The initial acute effect of the drug is believed to be opposed or counteracted by homeostatic changes in the systems that mediate primary drug effects.
Opponent-processes at play

Single exposure:

• State of neutrality (not feeling good or bad)
• Peak of primary emotion: every + emotion is opposed by a negative emotion in order for the system to return to normality
• Peak of opponent emotion: overshoots

Chronic exposure:

• The same stimulus: no longer produces strong emotion, is much weaker (less euphoria, more tolerance)
• Negative emotion becomes greater and withdrawal symptoms increase

Question 15

Explain the study with cocaine addicts looking at opponent processes like the allostasis and negative reinforcement models of drug use

Answer 15

After a single cocaine smoking session - there is a quick increase in plasma concentrations of cocaine which declines progressively

There was also a quick rise in euphoric feelings (self-report) which in 20 minutes, left people in neutral state. The 30 or so minutes after this, people reported negative affects, dysphoria, when cocaine was still in the blood before returning to normal again

Question 16

What us the allostatic process?

Answer 16

the process of trying to achieve stability through change - never a return to normality

• Mood never return to the original homeostatic level before drug-taking is reinitiated, thus creating a greater and greater allostatic state in the brains reward system.
  (downward spiralling)

Question 17

Explain how drug addiction can be a result from learning

Answer 17

Learning plays a key part in shaping our behaviour

• Classical conditioning:
  Ads for alcohol and tabacco - try to pair positive experiences with these drugs to elicit a positive emotional response from the viewer
  Also, some of the behaviours that addicts exhibit, are classically conditioned - drug craving (stimuli in the environment or specific contexts and places elicit craving to drive behaviour as have been conditioned)
• Instrumental conditioning: Organisms behaviour produces the stimulus
  Behaviour occurs because of the consequences it produces ‘goal directed behaviour’ towards reinforcement
• Observational learning: children learn from parents and are more likely to try drugs if their parents are regular drug users

Question 18

Explain the place preference paradigm

Answer 18

Explains contextual/place specific pavlovian conditioning for drugs

• Have 2 distinct locations
• Condition to experience drugs in one environment
• Develops preference to drugs in one setting - wanting drugs in one condition but not the other

Question 19

Explain a study demonstrating that drug-based behaviours can be goal directed and controlled by the consequences

Answer 19

Rats were places in a self-administration chamber with access to a lever that when they press, delivers a given amount of drug in the animal. They quickly learn that pressing this, produces favourable outcomes of receiving drug - quickly develop a highly stable pattern of drug SA

• If you manipulate the dosage so that rat is only getting half of the original amount they were receiving, their behaviour doubles. This indicates that the animal is sensitive to the outcomes. They will also reduce behaviour by half if given double the dosage

However - If you pretreat with dopamine blockers, the animal does not receive the effects of the drug anymore and will administer significantly more to try and get the effects of the drug

Question 20

What is habit learning?

Answer 20

The response occurs relatively automatically without much mental processing of the relation between the action and the outcome - overtraining of drug based behaviour drive behaviours automatically

The reason for this may be that it will free up cognitive capacity to do other things - eg. driving a car - when we are learning we can only focus on one thing at a time but when a practiced driver can have conversations etc while driving

Question 21

Which parts of the brain drive habitual learning?

Answer 21

Mediated by information transfer from the ventral striatum to the dorsal striatum

Question 22

Are there any studies with RODENTS looking at compulsive drug taking regardless of consequences?

Answer 22

Drug taking continues despite negative consequences

Looking at 2 animals:
1. Has a limited history with the drug and only just learned to self administer = goal directed to get euphoric effects of the drug. When a mild shock is delivered after administration, drug taking decreases as this animal is sensitive to the consequences.

2. this animal has an extended history with experience taking the drug - has developed a habitual pattern
   When a shock is administered the administration doesn’t change much as the animal is willing to tolerate consequences because they have developed habitual ways of responding instead of their behaviour being goal directed

Question 23

Are there any studies with HUMAN SUBJECTS looking at compulsive drug taking regardless of consequences?

Answer 23

PET scans to look at brain activity when shown a neutral video vs. a cocaine-cue video (scenes of subjects smoking cocaine)

Compared to control subjects, cocaine addicted subjects showed increased dopamine activity in the dorsal striatum (area mediating habit formation) - during this time subjects also reported craving

This shows that it is possible to think of drug addiction as a habit that forms overtime. Also explains why behaviour becomes insensitive to negative consequences
Evidence for which anatomical structures in the brain mediate these responses

Question 24

Addictive behaviours are a heterogenous phenotype - what does this mean?

Answer 24

Multiple factors influencing whether or not a person will develop an addiction

There are individual differences based on genetic differences, in upbringing, environmental and social influences and much much more

Question 25

How does personality make someone vulnerable to addiction?

Answer 25

Personality traits such as:
- disinhibition (behavioural activation)
- sensation seeking
- difficult temperament
- anxiety phenotype
- impulsiveness
Make people more vulnerable to drug addiction

Question 26

How do developmental factors contribute to drug addiction vulnerability?

Answer 26

There is strong evidence that suggests that early (adolescent) exposure to alcohol, tobacco, or drugs of abuse leads to significant vulnerability towards developing problems during adulthood.

Initiation often begins with legal drugs and involvement with illicit drugs occurs later in the development sequence - marijuana is often the bridge between legal and illegal drugs

Common but not inevitable

Question 27

How much to genes contribute to drug addiction? and how did they study this?

Answer 27

40%
Examining monozygotic and dizygotic twins
Not 100% so argues strongly for gene-environment interactions

Question 28

What did they find with studies on impulsive rats?

Answer 28

• Impulsive rats had significantly reduced D2 and D3 receptors in the nucleus accumbens
• Impulsivity in rats predicted high rates of intravenous cocaine self-administration

Question 29

Explain findings of the D2 and D3 receptors in human brains

Answer 29

Reduced availability was also present in brains of human addicts as well as obese people (activates common reward pathways) so eating is almost like an addiction

Shows non-drug addictions may share similar biological pathways

Question 30

What drug has caused more ill health and premature death than any other drug?

Answer 30

Tabacco

Question 31

Why has the proportion of smoking tabacco decreased?

Answer 31

Falls in tobacco smoking is mainly driven by younger generations not taking up smoking

Question 32

What is the most commonly used illicit drug?

Answer 32

Cannabis

Question 33

What are the four stages of substance use?

Answer 33

1. Initiation: beliefs (susceptibility, costs, benefits etc) and societal factors(parental behaviour, peer pressure) all feed into whether it is maintained
2. maintenance
3. cessation: self help, public health interventions (doctors advice, worksite interventions), clinical interventions (disease perspective, aversion therapy)
4. relapse: relapse prevention (coping, expectations, attributions)

Question 34

Why are relapse rates high?

Answer 34

after years of drug abuse, drug addiction becomes a chronic illness

Question 35

Which factors contribute to relapse?

Answer 35

Stress, conditioned cues, exposure to the drug itself

Question 36

What are the treatments that are available for relapse?

Answer 36

CBT
Group counselling
Pharmacological