PSYC 211 - Chapter 18

PSYC 211 - Chapter 18 - Chapter 18: Drug Abuse: Common...

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Chapter 18: Drug Abuse: Common Features of addiction All these substances: o Stimulate brain mechanisms, which are responsible for positive reinforcement o Reduce or eliminate unpleasant feelings A Little Background (Drugs) Recreational use Medicinal use Some consumed only locally Some become popular commercial crop p. 616: Figure 18.1 –Most important addictive drugs + site of action Positive reinforcement: Example: When a rat presses a lever, he receives food. He therefore; positive reinforced and the appetitive stimulus is activated. The brain then increases the likelihood of the most recent response (the lever press) in the present situation (the chamber that contains the lever) Addictive drugs have reinforcing effects on behavior The effectiveness of a reinforcing stimulus is greatest if it occurs immediately after a response occurs as we reason by immediate consequences (effects) for our actions (cause). The last response: the act of taking the drug (ie. Injection or inhalation) will reinforce the positive response gained from the drug use behavior (it will also takes precedence over quantity) Most addictive drugs= immediate effects o Ex: Morphine is less preferred than heroine who has more immediate effect as it is more lipid soluble and passes through the blood brain barrier faster. Users seek the “rush”. Why do people take drugs when they know the long term negative effects? The immediate reinforcing effects of an addictive drug can, for some overpower the long-term recognition of the long term effects. A minority who try addictive drugs continue on to become dependent o Cocaine: most addictive drug- 15% who use it become more addicted Brain mechanisms inhibit behavior for unfavorable long term consequences Slow acting routes can also be reinforced o The ability to remember the behavior causes the reinforcement of it as well as other cognitive processes such as expectation that the europhic effects will occur and other’s reinforcement of the drug (“you’ll get a high”) o Ex: If a person takes a pill and a few minutes later he experiences europhia, he will remember taking that pill Neural Mechanism: All natural reinforcers cause the release of dopamine in the nucleus accumbens o Ex: food for hunger The release is necessary for positive reinforcement to occur Negative Reinforcement: Definition : o The removal or reduction of an aversive (strong disliked) stimulus that is dependent on a particular response, with an attendant increase in the frequency of the response The response must make the unpleasant stimulus end or decrease 1
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o Ex: a woman hears an unpleasant noise (aversive stimulus) from her furnace and when she kicks it (the response), the sound goes away and the response is reinforced. (In contrast, punishment: makes the unpleasant stimulus occur)
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This note was uploaded on 02/13/2011 for the course PSYC 211 taught by Professor Yogitachudasama during the Winter '09 term at McGill.

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PSYC 211 - Chapter 18 - Chapter 18: Drug Abuse: Common...

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