L22 substance use disorder Flashcards
Substance use disorders
- Repeated use of a psychoactive substance or substances, to the extent that the user
- is periodically or chronically intoxicated;
- shows a compulsion to take the preferred substance (or substances);
- has great difficulty in voluntarily ceasing or modifying substance use;
- exhibits determination to obtain psychoactive substances by almost any means
Brain disease model of addiction (BDMA)
- a chronic brain disease characterised by compulsive use of substance(s) despite adverse consequences.
- the brain reward systems are altered following chronic drug use
DSM-4
- substance abuse and substance dependence
DSM-5
- substance use disorder
- addiction is not a diagnostic term
Substance-Related and Addictive Disorders
Substance-Related and Addictive Disorders
* Substance-Related Disorders
– substance use disorders
– substance-induced disorders
Diagnostic criteria for alcohol use disorder
- Impaired Control
- Social impairment
- RIsky Use
- Pharmacological criteria
SUD: Impaired control
- Taken in larger amounts over longer periods
- Desire or unsuccess in cutting down on it
- Craving it
SUD: Social Impairment
- Failure to fulfill roles in work, school or home
- Continued use despite problems
- outside things given up
SUD: Risky use
- Recurrent drug use in hazard situations
- Continued use despite knowledge
SUD: Pharmacological criteria
- Tolerance: increased amounts of alcohol
- Withdrawal
Operant (instrumental) conditioning
organisms learn to associate a behaviour and an outcome, and adjust the frequency or probability of a behaviour to achieve or avoid that outcome
Reinforcement
Increase the probability of a behaviour → outcome
Punishment
Decrease the probability of a behaviour → outcome
Positive reinforcement
- add a desirable outcome to increase the likelihood of a behaviour
- e.g., a driver receives a discount on car insurance for safe driving
Postivit punishment
- add an undesirable outcome to decrease the likelihood of a behaviour
- e.g., a driver gets a fine for speeding
Negative reinforcement
- remove an undesirable outcome to increase the likelihood of a behaviour
- e.g., a driver stops the “beeping” sound by fastening the seatbelt
Negative punishment
- remove a desirable outcome to decrease the likelihood of a behaviour
- e.g., a driver loses licence for unsafe driving
- primary rewards
(food, water and sex) - survival of organism
* the consummatory behaviour associated with these rewards is most rewarding
- non-primary rewards
, social rewards, can enhance the functions of primary rewards
produce learning
produce learning - a behaviour is required to obtain a reward
motivate approach behaviour and decision-
making - seek, obtain and consume a reward, and choose between different rewards
generate positive emotions,
- e.g., pleasure - experience pleasure from consuming a reward
In operant conditioning, a reward functions as a____ (pos or neg) reinforcer
positive
The brain reward systems
- ventral tegmental area (VTA)
- prefrontal cortex (PFC)
- nucleus accumbens (NAc)
Outcome of the reward systems
- produce pleasure
- form associative learning and memory
- stimulate the release of dopamine and predict the value of a reward
Positive reinforcement and SUD
- linked to euphoria;
- compulsive drug taking and its associated cravings dopamine mediates reward pleasure (“liking”)
- mesolimbic dopaminergic pathway
Pos reinforcement opioids and benzodiazepine
inhibition of VTA GABAergic neurons (green-slides) removed their inhibitory effects on VTA dopaminergic (DA) neurons (red)
Nicotine and psychostimulants in DA
- nicotine - depolarise DA neurons (red)
- psychostimulants - inhibit dopamine reuptake
Issues with positive reinforcement
Liking is not the same and wanting (this on is linked with the mesolimbic pathway)
“liking”
- behavioural or neuronal hedonic (pleasant) reactions
– mediated by endogenous opioids
“wanting” (or incentive salience)
- a form of desire that involves the mesolimbic dopaminergic pathway
– mediated by dopamine
learning
cues are associated with drug-related rewards - trigger “wanting” without necessarily producing “liking” for the same reward
Incentive-sensitisation theory
- Repeated drug use
- tolerance to “liking”
- sensitised mesolimbic dopaminergic pathway
- hyperreactive to incentive stimuli (e.g., drug-related reward cues- previous associative learning)
Negative reinforcement SUD
- linked to dysphoria; to remove unpleasant experience of withdrawal effects or anxiety
- cycle of Binge, withdrawal, and preoccupation (intox, neg, anticipation)
- Signif varies In order - psychostimulant, opioids, tobacco
Negative reinforcement: binge/intoxication
- brain reward systems, (mesolimbic pathway), leads to incentive salience (“wanting”):
- associate neutral cues with drug-related reward (learning)
- motivate approach behaviour (seek and consume a reward)
Negative reinforcement: withdrawal/negative affect
- amygdala produces negative emotions
- reduction in neurotransmission associated with acute drug reward effects, but drug-opposite response persists
Negative reinforcement: preoccupation/anticipation
- Impaired decision-making and self control
- prefrontal cortex provides excitatory control (med by glutamate) over the mesolimbic pathway
- deficits in executive functions (med by GABA in prefrontal cortex)
