1b Substance Use and Addiction Flashcards
What is meant by positive reinforcement?
Taking a substance to gain a positive state
What are some examples of reasons to take substances fot positive reinforcement?
Escapism
Get high
Like it
Stay Awake
What are some examples of reasons to take substances for negative reinforcement?
Boredrom
To get to sleep
Feel Better
Reduce Anxiety
What is negative reinforcement?
Taking substances in order to overcome an adverse state
Describe the course of alcohol/drug use which leads to addiction
- Experimental / recreational use which causes limited difficulties - “LIKE”
- Increasingly regular use - “WANT”
- Leads to harmful use as there is a shift in motivational desire
- Finally = spiralling dependance on the drug = “NEED”
What is the definition of a harmful substance?
A substance which when using it, places the mental and physical health of the user in danger
Hazardous = likely to cause harm if use continues at this level
What are the key diagnostic criteria of Dependance Syndrome?
- Strong desire or sense of compulsion to take the substance
- Difficulty controlling the substance in terms of termination of use - think who has control, you or the drug
- A physiological withdrawal state when the drug is stopped
- Tolerance = need to take more to get the same effect
- Neglect of alternative interests
- Persisting with substance despite clear evidence of harmful consequences
What is the definition of Addiction?
Compulsive drug use despite harmful consequences, characterised by an inability to stop using the drug; failure to meet work, social and family obligation and depending on the drug, tolerance and withdrawal
What is the biological definition of dependance?
Refers to a physical adaptation to a substance = Patients can be depedant but not addicted
What are behavioural addictions?
Gambling disorder = similarities in neurobiology and treatment approaches therefore reclassified
How does entry of the drug impact addiction?
faster brain entry = more “rush” and more addiction
Describe the path from use to addiction?
- Pre existing vulnerability - family history and age play large roles
- Drug exposure = compensatory neuroadaptations to maintain brain functions
- Leads to cycles of remission and relapse, or sometimes recovery which can be sustained
What happens once someone is tolerant to a drug?
Once they become tolerant, they then begin to experience withdrawal once the drug is not there
How does alcohol affect the brain?
Alters the balance between the brains inhibitory and excitatory systems
What is excitatory system of the brain?
Glutamate system
Which receptor does the glutamate system work on?
NMDA receptor
What is the inhibitory system of the brain?
GABA-A system
What are two common reasons to drink alcohol?
To get to sleep
To reduce anxiety
Describe the effects of acute alcohol drinking on the excitatory system?
Blocks the excitatory system = results in impaired memory (leading to blackouts)
How does memory get impaired with drinking alcohol?
Changes to the NMDA receptor result in memory loss
How does the inhibitory system get affected when acutely drinking alcohol?
Boosts the inhibitory system
- Sedation
- Anxiolysis
What does chronic alcohol exposure lead to?
Results in neuroadaptations so GABA and glutamate remain in balance in the presence of alcohol
What happens to the excitatory and inhibitory systems in chronic alcohol use?
Upregulation of the excitatory system and reduced function in the inhibitory system = tolerance
How does the GABA-A receptor change in chronic alcohol drinking?
Switch in sub-units to make it less sensitive to alcohol
Describe the withdrawal state of alcohol and what it can lead to
When the alcohol is taken away - there is still the large up-regulation of the excitatory system
This imbalance is toxic and can lead to hyperexcitability (seizures) and cell death (atrophy)
How does the NMDA receptor change in the state of withdrawal?
Increase in Ca2+
How is alcohol withdrawal treated?
Treat with benzodiazepines to boost GABA function to restore the balance and counteract the glutaminergic hyperactivity
What is the medication which reduces NMDA function?
Acamprosate
What do natural rewards (food, sex) do?
They increase the levels of dopamine in a part of the brain called the ventral striatum
What is the dopamine pathway referred to as?
Pleasure-rewards-motivation system
What is a key regulator of the dopamine system?
Opioid system - Mu opioid which mediates pleasureable effects - endorphin rush