Substance Use and Addiction Flashcards
What are the main three things to flag for abuse?
- quantity/frequency
- consequences (physical, psychological, social impact)
- dependence/addiction
What are the main red flags for dependence?
- tolerance and morning drinking
- withdrawal
What are the different types of stimulants?
- amphetamine
- cocaine (crack)
- ecstacy
What are ‘novel psychoactive substances’?
- new 1/week
- tend to be synthetic
- can be put into 4 categories: depressant, stimulant, hallucinogenic, cannaboid
Why is it important to know why drugs are being used?
Because it informs treatment
What is positive reinforcement (drugs)?
drugs are used to gain a positive state
What is negative reinforcement?
drugs are used to overcome an adverse state
What is the course of drug addiction?
- experimental use, causes no/limited difficulties
- increasingly regular until harmful
(can bounce back from here) - spiral into dependence
(point of no return) - like>want>need
What is the ICD-10 diagnostic criteria?
- strong compulsion to take the substance
- difficulties in controlling the substance (onset, termination or usage levels)
- negative physiological withdrawal when substance use is stopped
- tolerance: more to get the same effect
- neglect of alternative interest
- persistence with use despite harmful consequences
What classifies harmful use?
Actual damage should’ve been caused to the health of the user in the absence of diagnosis of dependence
- physical or mental damage (required)
- adverse social consequences
What is the estimated prevalence of alcohol dependence?
595,000 people
only 103,471 in treatment, 82% not receiving treatment
What is the estimated prevalence of opiate dependence?
257,476 people
170,032 in treatment, 46% not receiving treatment
What has been the impact of COVID-19 on alcohol and opiate dependency?
100% more people are at high risk
20% more cases
What is the definition of Addiction?
Compulsive drug use despite harmful consequences, characterised by the inability to stop using a drug; failure to meet personal, or professional obligations; and (drug dependent) tolerance and withdrawal
What is the definition of Dependence?
A physical adaptation to a substance
- tolerance/withdrawal
(can be dependent but not addicted)
What are some examples of behavioural addictions ?
- gambling disorder
(similar: neurobiology, treatment and co-morbidity and substance dependence) - internet gaming
What causes a larger ‘rush’ and addiction?
faster brain entry/onset
crosses the blood-brain barrier, lipophylic
What are the 3 main elements involved in alcohol/drug use and addiction?
- Social, environmental factors
- Personal factors (genetic)
- Drug factors
What are the changes to the brain pre and post addiction?
- pre-existing vulnerabilities, age and family history
- exposure leads to compensatory neuroadaptations to maintain brain function
- recovery: lead to cycles of remission and relapse
Why drink alcohol?
Alters the balance between the brain’s inhibitory (GABA-A, glutamate system) and excitatory system (glutamate system, NMDA receptor)
What impact does alcohol have on the excitatory system?
Blocks the excitatory system
- Impaired memory (alcoholic blackouts)
What is the impact of alcohol on the inhibitory system?
Stimulates the glutamate system
- anxiolysis
- sedation
What are the neuroadaptations caused by chronic alcohol exposure?
means that GABA and glutamate remain in balance in the presence of alcohol
- up-regulation of the excitatory system
- reduced function of the inhibitory system > tolerance
(switch in GABA-A receptors to make it less sensitive to alcohol)
How do you treat the neuroadaptation causing reduced function in the inhibitory system?
-benzodiazepines, to boost GABA function
What does the up-regulation of the excitatory system cause?
Increase in Ca2+, toxic leading to:
- hyper-excitability (seizures)
- cell death (atrophy)
What is Acamprosate?
drugs used to help people remain abstinent (reduced NMDA function)
- potentially neuroprotective (reduction in MRS glutamate)
What are the models of addiction?
- reward deficiency (positive reinforcement)
- overcoming adverse state (negative reinforcement)
- impulsivity/compulsivity
What is the neurobiology behind a withdrawal state?
In the absence of alcohol, GABA and glutamate are no longer in balance
Why are drugs addictive?
- increase the levels of dopamine
- activates the: ‘pleasure-reward-motivation’ system
What is a key modulator of the ‘pleasure-reward-motivation’n system
- mu opioid system
- mediates the pleasurable effects of drugs
What is the biological mechanism of cocaine and amphetamine?
- block dopamine re-uptake
- amphetamine: enhances the release of dopamine
What is the biological mechanism of other drugs (alcohol, opiates, nicotine)
Increase dopamine firing in the VTA (ventral tegmental area)
What are the possible impacts of dopamine D2 receptor levels on reinforcing responses?
- low D2 levels may predispose those to enjoy drugs
- high D2 levels may be protective
What is the impact of addiction on the reward system?
- blunted activation of the reward system (in abstinent addicts) due to the increased tolerance
What is the impact of a blunted response in the brain to reward anticipation?
- more likely to relapse
What region of the brain is involved in binge/intoxication?
- Dorsal Striatum
- Thalamus
- DGP
- VGP
What is the region of the brain involved in the withdrawal/negative effect?
- hypothalamus
- brainstem
- effectors (autonomic, somatic, neuroendocrine)
What regions of the brain are involved in preoccupation/anticipation?
- pre-frontal cortex
- hippocampus
- BLA
- Insula
What happens to the models of addiction as the addiction develops?
Changes from positive to negative reinforcement
What are the targets for treatment?
The brain regions associated with withdrawal
- the ‘reward’ system
- the ‘stress’ system
- the amygdala
What is the impact of withdrawal and negative emotional states on the ‘reward’ system?
- reduced dopamine
- reduced mu opioid function
What is the impact of withdrawal and negative emotional states on the ‘stress’ system?
increased activity in:
- kappa opioid (dynorphin)
- noradrenaline (arousal system)
- CRF (stress)
- etc…