Psych Substance use and addictions Flashcards
what is positive reinforcement?
- gaining positive state
- e.g. getting high
what is addiction?
compulsive drug use despite harmful consequences, characterised by an inability to stop using a drug. Failure to meet work, social or family obligations and tolerance and withdrawal
what is dependence?
physical adaptation to a substance
- tolerance/withdrawal
- can be dependent and not addicted
behavioural addictions
- gambling disorder
- internet gaming disorder
hazardous use meaning
A pattern of substance use that increases the risk of harmful consequences for the user. Some would limit the consequences to physical and mental health (as in harmful use); some would also include social consequences. In contrast to harmful use, hazardous use refers to patterns of use that are of public health significance despite the absence of any current disorder in the individual user. The term is used currently by WHO but is not a diagnostic term in ICD-10.
harmful use meaning
A pattern of psychoactive substance use that is causing damage to health. The damage may be physical (e.g. hepatitis following injection of drugs) or mental (e.g. depressive episodes secondary to heavy alcohol intake).
reasons for taking drug for recreational use
- boredom
- reduce anxiety
- get sleep
- wanting to fit in
what characteristic do you see in dependence?
- spiraling dependence
what drug (legal or illegal) is causing the greatest quotation of harm in our society?
alcohol
does dependence mean you take more of a drug than you should?
no
- however if withdraw need to taper the drug down.
what does the speed of a drug entering the brain determine?
how addictive it can be
- faster brain entry = more rush = more addiction
routes for tobacco taking effect?
chewing -> snuff -> cigarettes/vaping
routes for cocaine taking effect?
coca leaves -> coca paste
- > cocaine
- > crack
routes for heroine taking effect?
opium -> morphine -> heroin -> snorted heroine -> smoked heroin
How factors come together to alter how drugs impact the brain?
- social/environmental factors
- Personal factors e.g. genetic; personality traits
- Drug factors
what causes pre-existing vulnerability to a drug?
- family history
- age
what does exposure to a drug cause?
- compensatory neuroadaptations to maintain brain function
- resilience
what system balance does lacohol alter in the brain?
the balance between the brains inhibitory and excitatory systems
What neurons are in the excitatory system?
- glutamatergic
what neurons are in the inhibitory system?
- GABAergic
What happens to excitatory system when you drink alcohol acutely?
- blocks excitatory system
- impaired memory (alohol blackouts)
- No NMDA receptors
What happens to inhibitory system when you drink alcohol acutely?
- anxiolysis
- sedation
What is anxiolysis?
A level of sedation in which a person is very relaxed and may be awake.
What happens to excitatory system when you drink alcohol chronically?
- less NMDA receptors
- causes upregulation of the excitatory system
What happens to inhibitory system when you drink alcohol chronically?
- reduced function in inhibitory system
- however the GABA-A receptors switch their subunits to make them less sensitive to alcohol tolerance
What happens when you are a chronic drinker and withdraw alcohol suddenly?
withdrawal
What happens to systems when chronic alcohol exposure is withdrawn suddenly?
- upregulation of excitatory system
- reduced function in the inhibitory system
processes in excitatory system when chronic alcohol exposure is withdrawn?
NMDA receptors cause increase in Ca2+
- toxic leading to hyperexcitability (seizures) and cell death (Atrophy)
processes in inhibitory system when chronic alcohol exposure is withdrawn?
Reduced function
How to treat reduced function of inhibitory system during periods of withdrawal?
- treat with benzodiazepines to boost GABA function
What type of imaging can be used to measure the (low) glutamate levels during alcohol withdrawal?
MRI
what medication helps people remain abstinent from alcohol?
Acamprosate
How does acamprosate help people remain abstinent from alcohol?
reduces NMDA function
natural rewards (food, sex) increase levels of ____ in the part of the brain called the ___ ____
- dopamine
2. central striatum
what is the name of the dopamine- reward pathway?
the ‘pleasure-reward-motivation’ system
What is a key modulator of the pleasure-reward-motivation system?
the opioid system, especially MU opioid that mediates pleasurable effects (e.g. of alcohol, endorphin rush)
other modulators of the pleasure-rewards-motivation system?
GABA-B, cannabinoids, glutamate
which drugs block reuptake at dopamine synapses?
- amphetamine
2. cocaine
which drug enhances release of DA?
- amphetamine
which drugs increase dopamine firing in the VTA? (3)
- alcohol
- nicotine
- opiates
If you have lots of dopamine D2 receptors, do you like receiving psychostimulants?
no (maybe like schizophrenia when too much dopamine induces psychotic states)
- pleasurable effect seen in people with lower levels of receptors
what imaging is used in assessing function in the rewards pathway?
fMRI
- challenging because uses radiation
what light’s up on an fMRI in anticipation of receiving a rewards (e.g. money)
the ventral striatum
what can drug use cause to happen to the rewards pathway?
reward deficiency
- worst in people who are abstinent polydrug (e.g. opiate+alcohol), then abstinent alcohol dependent
fMRI shows what observation in adolescents who go on to develop drug issues?
reward deficiency
fMRI shows what development in people with addictions who relapse?
very blunted reward deficiency
- also in abstinent addicts, those with blunted response in brain to “anticipation of reward” are more likely to relapse
structures involved in the arousal-stress system which is active in withdrawal
- amygdala
2. the brainstem
what type of reinforcement wanes in people who become addicted?
- positive reinforcement
- becomes driven by negative reinforcement
what structure is dysregulated in anxiety disorders?
the amygdala
NTs increased in the arousal system when stressed
- CRF
- Dynorphin
- glucocorticoids
- hypocretin
- neuroimmune factors
- noradrenaline
- substance P
- vasopressin
NTs decreased (antistress) in the arousal system when stressed
- Neuropeptide gamma
- Nociceptin
- Oxytocin
- Endocannabinoids
left amygdala response for polydrug users (versus control_ when exposed to aversive images
heightened emotional response
-> alcohol users did not show a different response to the control however
what does the change from voluntary to habitual and compulsive drug use involve transition from?
- prefrontal to striatal control over drug taking changes
- > control goes from ventral (limbic or emotional) to dorsal (habit) striatum
- > becomes so dysregulated that it underpinds further drug use
what is the dorsal striatum area involved in?
- parkinsons disease and habits
how do you test the neurocircuitry involved in inhibitory control?
the go-nogo gauge
what happens in the cortex with increasing abstinence by an alcoholic?
increasing bold activity
- able to mount a greater response in the inhibitory response may lead to successful abstinence?
what treatments can enhance treatments in the part of your brain involving inhibition and therefore help you stay abstinent?
- drugs
- psychological treatments
what is the function of naltrexone?
it’s an opioid antagonist that blocks heroine use in opioid addicts
- modulates rewards system in alcoholism
what drugs would be useful to develop to treat addiction?
anti-stress medications
