substance abuse & addiction Flashcards
What are reasons people take recreational drugs?
Reduce anxiety, get high, rebel, boredom, escapism, why not, feel better, like it, stay awake, sleep, curious, fit in, everyone does
What is positive and negative reinforcement in terms of drug use?
- Positive reinforcement is to gain a positive state (eg get high, stay awake, escape).
- Negative reinforcement is to overcome adverse state - eg reduce anxiety, sleep, feel better.
Why is it important to know why they take drugs?
it informs treatment
What is harmful substance use according to ICD-10?
Actual damage should have been caused to mental or physical health of user in absence of diagnosis of dependence syndrome.
What is hazardous use?
Likely to cause harm if continues at this level
Why do people become dependent on a drug?
neuroadaptations
What is needed for diagnosis of dependence syndrome according to ICD-10 diagnostic criteria?
- strong desire or sense of compulsion to take substance 2. difficulties controlling substance taking behaviour (onset, termination, level)
- physiological withdrawal state when substance use has stopped/reduced
- evidence of tolerance (need to take more for same effect)
- progressive neglect of alternative interests
- persisting with substance use despite clear evidence of overtly harmful consequences .
Need 3 of these in past months
What is addiction?
Compulsive drug use despite harmful consequences, characterised by inability to stop, failure to meet work, social or family obligations & depending on drug, tolerance & withdrawal
What is dependence?
Physical adaptation to substance. Tolerance/withdrawal. Can be dependent but not addicted
What are behavioural addictions?
Gambling disorder, internet gaming disorder.
Similarities in aetiology, neurobiology & treatment approaches with substance dependence.
What does rate of brain entry of a drug affect?
Faster brain entry causes more rush and more addiction (increases addictive potential)
What factors affect addiction?
Genes, family history (more vulnerable to misuse), social/environmental factors, drug factors (faster entry)
What is tolerance?
Need to increase dose to get same effect or suffer withdrawal
What happens during acute alcohol exposure?
Alcohol blocks excitatory system NMDA receptor (impaired memory, blackouts) and boosts inhibitory system (anxiolysis, sedation) at GABA-A receptor
What happens during chronic alcohol exposure?
Neuroadaptations so that GABA and glutamate remain in balance in presence of alcohol.
-Body adapts to reduce sensitivity of GABA (reduces function of inhibitory system) by switch in subunits of GABA-A receptor making it less sensitive to alcohol, and up-regulation of excitatory system
What happens during the alcohol withdrawal state? What do we give and why?
Inhibitory system is downregulated, excitatory system is upregulated.
- Withdrawal symptoms because more NMDA receptor, increase in calcium ion entry in cell which is toxic, leading to hyperexcitability (seizures) and cell death (atrophy).
- We give benzodiazepines to boost GABA function and combat excitatory system
What is acamprosate?
Drug to help people remain abstinent by reducing NMDA function - reducing glutamate levels in brain.
What is the dopaminergic system and what do rewards cause?
- Reward-motivation system.
- Natural rewards increase dopamine in ventral striatum. Going towards dependence, dopamine system becomes more about needing drug.
- Key modulators in opioid system (endorphin modulators) and GABA-B, cannabinoids, glutamate targets for treatment
What is addiction thought of as?
Reward deficient state so take drug to increase reward
What do drugs do to dopamine?
Amphetamines and cocaine block reuptake of dopamine and enhance release of dopamine.
Other drugs like alcohol and opiates increase dopamine neurone firing in VTA
What is relationship between D2 receptor availability and liking a stimulant drug?
- Those with more D2 receptor availability did not really like stimulant drugs.
- Less D2 receptor availability liked stimulant drugs (may be reward deficient - less baseline dopamine levels)
What can be seen in fMRI during anticipation of winning?
Ventral striatum lights up (dopamine)
Difference in reward system between controls, abstinent and relapse?
Blunted activation of reward system in those with relapse, a bit better in abstinent, a lot better in controls
Do all addicts have blunted reward system?
no
