Substance Use And Addiction

Question 1

Drugs to be aware of

Answer 1

• Alcohol
• Nicotine
• Cannabis
• Stimulants
• Amphetamine
• Cocaine (including crack)
• Ecstasy
• Opioids
• Heroin, fentanyl
• DF118
• Ketamine
• Solvents
• GHB, GBL
• Benzodiazepines
• Psychedelics
• LSD
• Magic mushrooms (Psilocybin)
• Nitrous Oxide
• Khat
• Novel psychoactive substances
• may be depressant, stimulant, hallucinogenic, cannabinoid

Question 2

Reasons of drug use

Answer 2

Positive reinforcement - to achieve a positive state:

• To get high
• To stay awake
• As a form of escapism
• Because they like it

Negative reinforcement - to overcome an adverse state:

• Boredom
• Anxiety reduction
• Helps them sleep
• Helps them feel better

May also be for other reasons:

• Why not?
• To fit in
• May be curious
• Everyone does

Question 3

Course of drug use

Answer 3

• Liking (experimental and recreational use, with few difficulties, most of the population)
• Wanting (increasingly regular use, fewer number of people)
• Needing (harmful, may not even enjoy the drugs anymore, smaller number of people)

Question 4

Definition of dependence syndrome in ICD10

Answer 4

1. A strong desire or sense of compulsion to take a substance
2. Difficulties in controlling substance taking behaviour in terms of onset, termination or levels of use
   Useful questions in clinic:
   - Who has control, patient of the drug?
   - When did you last have a drink or take the drug?
   - Do you take any drugs?
3. A physiological withdrawal state when the substance use has is stopped or reduced
   - May range from uncomfortable to intolerable
4. Evidence of tolerance
   - need to take more for the same effect
5. Progressive neglect of alternative interests
   - Narrowing of repertoire, neglect of work etc
6. Persisting with substance use despite evidence of overtly harmful consequences
   - Not a moral failing, the patient is addicted so choice does not factor in

Question 5

Impact of drugs in the NHS

Answer 5

Alcohol most damaging in the UK,following heroine,crack,cocaine and methamphetamine
Death rate from opiates and cocaine is the highest

Question 6

Addiction

Answer 6

compulsive drug use despite harmful consequences, characterised by inability to stop using the drug, failure to meet work, social or family obligations, and tolerance and withdrawal

Question 7

Dependence

Answer 7

physical adaptation to the substance, such as tolerance and withdrawal. Possible to be dependent but not addicted

Question 8

Behavioral addictions

Answer 8

Gambling disorder (higher suicide rates than depression)
Internet gaming disorder

Question 9

3 main levels of problems

Answer 9

1. Quantity / frequency of use - hazardous use
   - May result in pathology, even if no social impacts
2. Consequences - harmful use
   - Physical, psychological, social impact
3. Pattern - dependence / addiction
   - Withdrawals may be a problem

Question 10

Medical cannabis

Answer 10

An alternative to opioids as an analgesic so may be prescribed to prevent opioid addiction

Question 11

Method of administration

Answer 11

The faster the entry into the brain the higher the rush and more thus lends to addiction

Examples:

Opium ⇒ Morphine ⇒ Heroin ⇒ Snorted heroin ⇒ IV or smoked heroin

Coca leaves ⇒ Coca paste ⇒ Cocaine ⇒ Crack

Chewing tobacco ⇒ Snuff ⇒ Cigarettes ⇒ Vapes

Question 12

Three factors which determine susceptibility to drug abuse

Answer 12

1. Social and environmental factors (legality, social perception)
2. Drug factors (how quick they reach the brain)
3. Personal factors (genetics, personality traits, age, poverty, family history)

Question 13

Progression to addiction

Answer 13

• Pre existing vulnerability (family history, age etc.)
• Drug exposure (compensatory neuroadaptations to maintain brain functions, though some people are resilient)
• Recovery (either as part of a remission and relapse cycle, or sustained)
• Relapse can kill, as tolerance is no longer so strong

Question 14

Effects of alcohol

Answer 14

• Release of GABA - calms people down, makes them more sociable
• Blocks glutamate system in order to make people sleepy, ataxic, and causes memory loss
  gaba is the inhibitory system and glutamate is the excitatory

Question 15

GABA and glutamate

Answer 15

Gaba system is the inhibitory system, and glutamate is the excitatory system, so drinking knocks this system out of balance, resulting in sedation
GABA system is enhanced before glutamate system is blocked so anxiolysis and sedation occur before impaired memory
Neural compensation occurs in chronic alcohol exposure by increasing levels of NMDA for glutamate and reduced function in the inhibitors system by switching gaba receptor subunits which causes tolerance

Question 16

What happens when someone stops drinking

Answer 16

As a result, when one stops drinking, a patients brain may be in an excitable state. This glutamate hyperactivity results in hangovers, and can lead to further addiction.

Withdrawals maybe treated with benzodiazepines to boost GABA function.

Question 17

Models of addiction:reward deficiency (positive reinforcement)

Answer 17

• Food, sex, and some addictive drugs release dopamine in the Ventral Striatum
• This is the pleasure-reward-motivation system
• Modulators of pleasurable effects include the mu opioid, GABA-B, cannabinoid, and glutamate systems
• Addiction has therefore been conceptualized as a reward deficient state

Interaction between substances of abuse and dopamine:

• Cocaine and amphetamine block dopamine reuptake
• Amphetamine enhances dopamine release
• amphetamines keep you awake and help ADHD function because they increase attentional capacity due to these effects

Question 18

How is degree of motivation assessed

Answer 18

Degree of Motivation may be assessed with fMRI via a Monetary Incentive delay task

Individuals with addictions are less motivated in these tasks - their rewards systems may be thought of as blunted

Higher activity in reward pathways is associated with more abstinence at follow up
Those with more blunted responses in the brain to anticipation of rewards are therefore more likely to relapse.
(is this why individuals with ADHD are less likely to develop addictions if on pharmacological therapy?)

Frontal regions are involved in decision making and impulse control

Limbic system is involved in adverse consequences of not using a drug, and craving drugs

Question 19

What’s the second model of addiction

Answer 19

Impulsivity and compulsivitiy

Question 20

3rd model of addiction

Answer 20

Overcoming adverse states (negative reinforcement)

Addiction is a process - initial use gives some pleasure (besides smoking)

Therefore the model of addiction transforms from positive to negative reinforcement as addiction develops, because pleasure then comes from not being in the negative, adverse withdrawal state

Question 21

How can you assess the function of the amygdala

Answer 21

You can assess the function of the amygdala via fMRI
- Emotional processing of aversive images compared to neutral images
- In withdrawal, the amygdala function is overactive
- Trauma activates the amygdala, which tries to then dampen down stress via learned behaviour

Question 22

How can you assess the neurocircuitry behind inhibitory control

Answer 22

With fmri

go-nogo task
- individuals with addictions show poorer decision making
- Greater response in the frontal pole / inferior gyrus in abstinent alcoholics, with a positive relationship between length of abstinence and scale of response
- Alcohol therefore has a large effect on the frontal lobe, hence the dementia like effects in chronic alcohol use

Question 23

Novel Psychoactive Substances:

Answer 23

Spice is one example, which is upto 100x more potent than THC

Many made, to replace older ones which have been banned