Summary Opioid addiction

Opioid addiction
What is substance use disorder?
 same as addiction
 fewer negative connotations compared to the term “addiction”
 people have compulsive behaviour in taking a drug
 this can cause detrimental impacts on their health
 driven by neurobiology not always due to patient’s fault
 causes a change in the brain
Causes of substance misuse
- genetic
- neural causes
- environment
- social pressures
Why does this occur?
 to feel good
 to get new experiences
 to have fun and relax
 to feel better
 lessen anxiety
 lessen worries
 lessen fears
What is ICD11?
 commonly used within the UK
 identifies different disorders in patients
 breaks down conditions
 e.g. into the substances used etc
 similar criteria to DSM-5
How does DSM5 and IC11 differ?
- DSM-5 focuses specifically on mental disorders and provides detailed criteria for
diagnosis, including symptoms, duration, and functional impairment. Is American
- ICD-11 is by WHO, covers a broader range of health conditions, including physical
illnesses, injuries, and mental disorders. It's used globally for coding diagnoses and
statistical purposes in healthcare.
Why can drugs be addictive? How does this occur?
 affects the brain reward system e.g., dopamine pathway
 Many drugs, including stimulants like cocaine and amphetamines, increase the
release of dopamine striatum and nucleus accumbens
 This creates a surge of pleasure or euphoria
 Reinforces the behaviour that led to the drug use
What is the nucleus accumbens?
- a major component of the ventral striatum
- interface between motivation and action
- playing a key role on feeding, sexual, reward, stress-related, drug self-administration
behaviours
What parts of the brain determine decision making?
- Nucleus accumbens with the prefrontal cortex

, Why does withdrawal and craving symptoms occur?
 With repeated drug use,
 the brain adapts to the presence of the drug
 by adjusting its natural dopamine production and receptor sensitivity.
 Over time, this can lead to tolerance, where higher doses of the drug are needed to
achieve the same effect,
 and dependence, where the person feels they need the drug to function normally.
What does the intensity of withdrawal effects depend on?
- how quickly the drug gets into the brain
- this will be dependent on the route of administration
- fastest: smoking, snorting and IV
- oral: takes a lot longer to have an effect
What is the hedonic effect?
- Surge in pleasure
- Drug starts to work
- Greater the surge the greater the pleasurable effect
Explain what occurs during the addiction cycle
- initial exposure
o gives hedonic effect
o surge in dopamine release in the nucleus accumbens
- effect wears off
o drug no longer present
o decreased dopamine levels
o neutral or negative effect on mood
- preoccupation
o want to get the pleasurable effect again
- repeated use
o frequency of use increases
o more drug required to produce same pleasurable effect as initial use
o dopamine receptors decrease in number
What is neuroplasticity?
 it can lead to changes in the brain's structure and function, which is often referred to
as neuroadaptation.
 Chronic drug use can lead to changes in the connections between neurons and the
strength of these connections.
 This rewiring of neural circuits can alter the brain's response to drugs and other
stimuli
 leading to increased drug-seeking behaviour and decreased sensitivity to natural
rewards.
 at the VTA and accumbens
 and it forms drug-related memories by the hippocampus
What part of the brain is associated with impulsivity?
 orbitofrontal frontal and medial prefrontal cortex
What is amygdala?
 part of the emotional response
 stress and cravings
 stress: release of cortisol and stimulation of the sympathetic nervous system