Substance Use And Addiction Flashcards
Drugs to be aware of
- 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
Reasons of drug use
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
Course of drug use
- 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)
Definition of dependence syndrome in ICD10
- A strong desire or sense of compulsion to take a substance
- 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? - A physiological withdrawal state when the substance use has is stopped or reduced
- May range from uncomfortable to intolerable - Evidence of tolerance
- need to take more for the same effect - Progressive neglect of alternative interests
- Narrowing of repertoire, neglect of work etc - Persisting with substance use despite evidence of overtly harmful consequences
- Not a moral failing, the patient is addicted so choice does not factor in
Impact of drugs in the NHS
Alcohol most damaging in the UK,following heroine,crack,cocaine and methamphetamine
Death rate from opiates and cocaine is the highest
Addiction
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
Dependence
physical adaptation to the substance, such as tolerance and withdrawal. Possible to be dependent but not addicted
Behavioral addictions
Gambling disorder (higher suicide rates than depression)
Internet gaming disorder
3 main levels of problems
- Quantity / frequency of use - hazardous use
- May result in pathology, even if no social impacts - Consequences - harmful use
- Physical, psychological, social impact - Pattern - dependence / addiction
- Withdrawals may be a problem
Medical cannabis
An alternative to opioids as an analgesic so may be prescribed to prevent opioid addiction
Method of administration
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
Three factors which determine susceptibility to drug abuse
- Social and environmental factors (legality, social perception)
- Drug factors (how quick they reach the brain)
- Personal factors (genetics, personality traits, age, poverty, family history)
Progression to addiction
- 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
Effects of alcohol
- 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
GABA and glutamate
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
What happens when someone stops drinking
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.
Models of addiction:reward deficiency (positive reinforcement)
- 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
How is degree of motivation assessed
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
What’s the second model of addiction
Impulsivity and compulsivitiy
3rd model of addiction
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
How can you assess the function of the amygdala
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
How can you assess the neurocircuitry behind inhibitory control
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
Novel Psychoactive Substances:
Spice is one example, which is upto 100x more potent than THC
Many made, to replace older ones which have been banned
Different brain areas involved jn addiction
Reward deficiency/positive reinforcement occurs in dopaminergic mesolimbic system
Negative reinforcement occurs in amygdala and dysregulates stress system,increases kappa/dynorphin opioid system and noradrenegeruc activity
Impulsivity/compulsivity involved in frontal striata, connections with reduced frontal control of striatal activity and move from ventral (Limbic) to dorsal (habit) striatum as dependence develops
