Lecture 8 - Addiction

Question 1

What is addiction?

Answer 1

Dysfunction in brain reward, motivation, memory and related circuits leads to an individual pathologically pursuing reward and/or belief by substance use and other behaviours.

Question 2

What is drug addiction?

Answer 2

A chronically relapsing disorder characterised by:

• compulsion to seek and take the drug
• loss of control in limiting intake
• emergence of a negative emotional state, such as dysphoria, anxiety or irritability, when access to the drug is prevented.

Koob and Volkow, (2009)

Question 3

What is dysphoria?

Answer 3

A state of unease or dissatisfaction

Question 4

What is the difference between impulsions and compulsions?

Answer 4

Impulsions are rewarding acts carried out without thought, whereas compulsions are acts carried out to reduce negative states.

Question 5

What are the current goals of research into addiction?

Answer 5

To understand the mechanisms that are involved in the transition from occasional, controlled drug use to the loss of behavioural control over drug-seeking, drug taking, and to chronic relapse.

Question 6

Describe positive reinforcement in drug addiction.

Answer 6

Impulsions; increased tension/arousal before drug taking, and pleasure & relief at the time of consumption

Question 7

Why can drug addiction be characterised as both an impulsive and compulsive disorder?

Answer 7

Drug addiction results from both:

• positive reinforcement (impulsions; increased tension/arousal before drug taking, and pleasure & relief at the time of consumption)
• negative reinforcement (compulsion; anxiety and stress before and relief from the stress after the behaviour/consumption)

Question 8

Describe negative reinforcement in drug addiction.

Answer 8

Compulsion; anxiety and stress before and relief from the stress after the behaviour/consumption

Question 9

Define impulsivity

Answer 9

A predisposition towards rapid, unplanned reaction to internal and external stimuli, without regard for the negative consequences for themselves or others.

Question 10

What are the ways that impulsivity can be measured?

Answer 10

Two ways:

• the choice of a smaller, immediate reward over a larger, delayed reward
• the inability to inhibit behaviour by changing the course of action/to stop a response once it has been initiated.

Question 11

What does ***Koob and Volkow (2009) propose as the addiction cycle?

Answer 11

• binge/intoxication: drug is taken due to very little consideration for consequences, but taken primarily for the potential reward (impulsive)
• withdrawal/negative affect
• preoccupation/anticipation - craving
• repeat

Repeats until positive reinforcement decreases influence as a motivator, and negative reinforcement comes to prominence - occurs at higher levels of substance dependence. Eventually individuals that are addicted will want to perform the behaviour just to relieve the negative affect, not even because they want to perform it.

The intensity of the affect/reinforcement also increases as the substance dependence does.

Question 12

What activation is there consistently, with rewarding drugs?

Answer 12

Whatever drug you take that is rewarding, it will light up your nucleus accumbens.

During the binge stage, you are chronically lighting up your N.A. The brain likes homeostasis, to continue our physiological states. Brain tries to counter the effect of the drug.

Question 13

How can the brain counter the effects of rewarding drugs?

Answer 13

Within system neural adaptation. - the primary response of the brain to neutralise the drug’s effects by increasing the brain’s reward threshold, specifically in the nucleus accumbens.

This then opens oneself up to addiction, with greater doses required to elicit reward in the future. This means greater doses of the same drug, or perhaps a stronger drug, in order to get the same rewarding feeling.

Also, everyday activities are no longer as rewarding.

Question 14

Define the withdrawal effects after chronic drug taking.

Answer 14

The persistence of the opposing effects of the body after the drug disappears.

The body continues to fight in the opposite direction to the drug even after the drug is no longer in the system.

Best way to metabolise and get rid of the drug is to raise cortisol levels, Increasing levels of cortisol is achieved by mediating the HPA axis (hypothalamic-pituitary-adrenal axis).

But after the drug is removed, the level of cortisol in the system lingers for some time, leading to the negative/anxious states we see in withdrawal.

Question 15

What is the HPA axis responsible for?

Answer 15

Releasing the level of cortisone in the system.

Question 16

What is one of the bad things cortisone does?

Answer 16

It causes damage to the hippocampus, leading to reductions in volume and efficiency. (Cortisone is neurotoxic)

Immune system, digestion and other drives such as sex drives are decreased when high levels of cortisol are present.

Question 17

What are some of the good things cortisone does?

Answer 17

Increases metabolism, reduces inflammation.

Question 18

What is between system neural adaptation?

Answer 18

Neurochemical systems other than those involved in the positive rewarding effects of drugs of abuse are recruited or dysregulated by chronic activation of the reward system.

Question 19

What regions are thought to be involved in the pre-occupational/anticipation stage?

Answer 19

• amygdala
• hippocampus
• PFC

Question 20

How is the amygdala involved in the pre-occupational/anticipation stage?

Answer 20

Recruited for the processing of conditioned reinforcement (emotional processing)

Question 21

How is the hippocampus involved in the pre-occupational/anticipation stage?

Answer 21

Environmental context influences cognitive processing (environmental cues could trigger cravings)

Question 22

How is the PFC involved in the pre-occupational/anticipation stage?

Answer 22

Cognitive control - representation of contingencies, representation of outcomes, and their value.

Trying to plan, evaluate the environment, identifying the consequences of taking the drug, justifying the actions needed to obtain/take the drug.

Question 23

What evidence is there that moving to a new city and having a new group of friends could help overcome an addiction?

Answer 23

First seen that, in a group of veterans, addictions could be lost. The vets were addicted to opium in Vietnam, but stopped taking them when they were home (new city, new friends, etc) - and had no cravings.

Then, when they returned to Vietnam, the addiction returned and intense cravings began again.

Due to environmental/contextual cues which trigger the cravings.

Question 24

What are some personality traits/individual risk factors for addiction?

Answer 24

• impulsivity - makes you more likely to try out a drug in the first place
• risk taking - behaviours performed without certainty/without thought for negative consequences.
• some genes which influence the metabolism of drugs
• some genes which are related to novelty-seeking
• stress responsivity (over-active HPA/cortisol response systems could lead to greater vulnerability for addiction)

Question 25

What did Veilleux et al., (2010) find about opioid treatment for addiction?

Answer 25

Opioid receptors are the receptors in the nucleus accumbens.

Opioid agonists replace dopamine, and bind to opioid receptors. They mimic the drug, but they aren’t as rewarding as the drug. Reduces withdrawal.

Opioid antagonists block the receptors completely, causing withdrawal.

Most drugs involves a combination of both antagonists and agonists.

Question 26

What did Veilleux et al., (2010) find about the detoxification?

Answer 26

Detoxification, in and of itself, is not considered a true ‘treatment’ for opioid dependence.

Abrupt termination of opioid use using opioid antagonists, along with the administration of adrenergic agonists can produce the detoxification effect, and reduce withdrawal symptoms.

Tapering - process of slowly decreasing a replacement opioid agonist. Longer treatment duration, fewer side effects improves treatment completion.