Substance Abuse and Addictions Flashcards
Define Harmful Substance Use
Actual damage should have been caused to the mental or physical health of the user in the absence of diagnosis of dependence syndrome.
Define Hazardous Use
Likely to cause harm if continued at this level
What are the criteria for Dependence Syndrome?
a strong desire or sense of compulsion to take the substance
difficulties in controlling substance taking behaviour in terms of its onset, termination, or levels of use
who has control, you or ‘the drug/behaviour’?
when did you last have a drink/drug?
a physiological withdrawal state when substance use has stopped or been reduced
- a ‘negative’ state (from uncomfortable to intolerable) so user takes drug/alcohol to ger relief from it or ‘treat’ it
evidence of tolerance: need to take more to get same effect
progressive neglect of alternative interests
persisting with substance use despite clear evidence of overtly harmful consequences
Define Addiction
compulsive drug use despite harmful consequences, characterized by an inability to stop using a drug; failure to meet work, social, or family obligations; and, (depending on the drug) tolerance and withdrawal.
Define Dependence
dependence refers to a physical adaptation to a substance
Tolerance/withdrawal
Eg opioid, benzodiazepine, alcohol
So can be dependent and not addicted
What are some common Behavioural Disorders?
Gambling Disorder
Internet Gaming Disorder
How many people drink more than 14 units?
21%
6% Dependent
10.4 million drink at a level that increases their risk of health problems
What symptoms characterize Dependence?
Tolerance & Withdrawal
What is the relationship between faster brain entry and addiction?
Faster brain entry = more “rush” and more addiction Faster onset related to speed of reaching the brain, crossing the blood-brain barrier, lipophylic.
What is the journey from alcohol use to addiction?
Pre-existing vulnerability; Family history, age
Drug exposure; Compensatory neurpoadaptations to maintain brain function
What is the Brain’s Excitatory system?
Glutamate system
NMDA Receptor
What is the Brain’s Inhibitory System?
GABA-benzodizepine
(GABA-A) System
Sedation
Anxiolysis
What does alcohol do to the brain?
Alcohol alters the balance between brain’s inhibitory and excitatory system
What happens to the GABA-A system, acutely, when you drink alcohol?
Boosts Inhibitory activity, more benzodiazepine coupling, while at the same time blocking excitatory system (impaired memory)
At the same time you have upregulation of the NMDA System so you have a new balance
What ar the adaptations to chronic alcohol use?
Reduces GABA-A system sensitivity, subtype switched to one that is less sensitive to alcohol.
What is one of the genetic underpinnings of alcohol?
You have a less sensitive GABA receptor
What gives you the symptoms of alcohol withdrawal?
Disturbance to this system means you have a downregulated inhibitory system, and an upregulated excitatory system, this imbalance causes alot of the toxic side effects.
How can you get a seizure as a result of alcohol withdrawal?
Disturbance in system balance NMDA Upregulation NMDA is a Ca channel More calcium channels open Hyperexcitability can lead to seizures
Why is benzodiazepine given as a treatment?
Boost the GABA system to achieve a balance
What drug reduces NMDA function?
Acamprosate is a medication to help people remain abstinent – it reduces NMDA function
What is a key modulator of the dopamine pathway?
A key modulator is opioid system – particularly mu opioid that mediates pleasurable effects (eg of alcohol, ‘endorphin ‘rush’); others include GABA-B, cannabinoids, glutamate etc that are targets for treatment
What can addiction be conceptualized as?
Award Deficient state
Describe the dopamine pathway?
Dopamine released, attatches onto receptor on post-synaptic cell, dopamine reutpake in presynaptic terminal.
Drugs such as cocaine block re-uptake, Amphetamine releases more dopamine. they directly block re-uptake which makes them so potent.
Other drugs increase dopamine neuron firing.
How can you predict people liking a drug’s effects?
Less D2 receptors, more pleasant feeling to stimulant
What is the relationship between Higher activity in the reward pathway and abstinence?
in abstinent addicts, those with blunted response in the brain to ‘anticipation of reward’ are more likely to relapse
consistent with ‘reward deficiency’ theories of addiction
What are the three stages of negative pathways?
Binge/intoxication
Withdrawal/Negative affect
Preoccupation/Anticipation craving
What is involved in the Withdrawal/Negative affect stage?
Amygdala involved, Hypothalamus + Brainstem effectors (autonomic/somatic). Disregulation of the amygdala IS KEY, hormones peptides go into oeride.
How do you go from positive to negative drug effects?
Become more tolerant
High gets less, withdrawal becomes bigger, more about overcoming negative state than getting high. Motivation is primarily driven by negative enforcement
What are the systems associated with negative emotional states in addiction?
The ‘stress’ system: increased activity in many including kappa opioid (dynorphin), noradrenaline (arousal system) CRF (stress) etc
What are the systems involved in the positive emotional states of alcohol?
The ‘reward’ system:
reduced dopamine and mu opioid function
How do you assess amygdalar function with fMRI?
Emotional processing of aversive images
Heightened brain response in left amygdala in abstinent polydrug addicts to aversive images but not in alcoholism
What transition is involved from voluntary to compulsive drug use?
Change from voluntary drug use to more habitual and compulsive drug use involves transition from:
prefrontal to striatal control over drug taking
i.e. prefrontal ‘top-down’ control is diminished with greater striatal reward drive
ventral (limbic or emotional) to dorsal (habit) striatum.
Role for ‘memory’ (eg hippocampus) in craving
How do you assess neurocircuitry involved in inhibitory control with fMRI?
go-nogo task
What is the response in alcoholics with greater abstinence?
Greater response in frontal pole/inferior frontal gyrus during inhibiting response in abstinent alcoholics:
greater response associated with longer abstinence
