?When people first thought about it (and until relatively recently) drug taking behaviour just seemed odd
–Not avoiding pain
–Doesn’t affect all people the same way
–You don’t ‘need’ it
?Aha! You must be an immoral pig, probably with little willpower. You are a bad person you junkie lowlife
?Oh perhaps it is not a problem with your character or morality?Ahh, yes, it is a disease
–Or a disorder as we say today
?Started with alcoholism
?What is the disease mechanism?
?But it is genetic!
?Withdrawal (from morphine) caused by ‘autotoxin’?Found to be lacking, but, the idea stuck. ?Indeed, still VERY popular
?Accounts for the ‘abnormality’ of it all
?Can be combined with the disease model
–Tatum and Seevers (1931) added habituation
?Problem is, that stimulants, for the most part, don’t produce withdrawal symptoms
?Hmm, Let’s invent a new idea!
?When you need a drug, but don’t need a drug?When you crave a drug
–Continual abuse with drugs that do NOT produce withdrawal–Addiction without dependence
?People used to think you couldn’t get animals addicted
–Can’t get the disease
?Work for drug
–(Thompson and Shuster, 1964)
?Seems circular, until you realize that we know what a reinforcer is not just from operational definition, but from physiology
–VTA -> MFB -> ACC
?Morphine to PVG leads to dependence, to ACC, does not!
?Shuster’s other work
–Rats will work for drugs not causing withdrawal–Rats will work for drugs without dependence!
?Is hard to get them to take things orally though?Pickens and Thompson (1968) found that drug use follows the laws of learning!
?Well, umm Yes
?Explains the paradox of positive and negative effects of drugs?Choice in taking a drug depends on other available reinforcers
–Hayman says it follows the matching law!
?Basically applying the ‘laws’ of economics to behaivour?Elasticity of demand is a biggie
?Caroll’s (1993) data on PCP
–Demand changed from elastic to inelastic, depending on price. –Inelastic at low prices
?Different prices (number of responses) for drug
?Demand inelastic, until it gets expensive
?If there is something else available (saccharin in this case) the monkeys will switch to it (substitution)
?Drug taking behaviour can be easily modeled using animals
–We all follow the laws of learning
?Not all drugs will be self administered by all animals, so be careful