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Wake Up and Smell the Caffeine

Psychology 2800

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Introduction The most popular psychoactive

drug in North America How many people here DO NOT

ingest caffeine?

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Introduction That includes:

Coffee 130 mg Tea 40 mg Soft Drinks (colas) 30 – 90 mg Cold and Headache medications

15 – 50 mg Rev ?, probably about 100 mg Chocolate! 50 – 100 mg Wake up pills 100 – 500 mg

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Introduction Almost always taken orally,

absorbed in small intestine. Crosses all barriers Absorbed more slowly from cold

beverages Less than 2% is excreted

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Metabolism Half life is between 30 min and 3.5

hr Metabolism slowed by birth control

pills Sped up by broccoli! 2x faster in smokers

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Metabolism That was with adults (well not kids

anyway) Different deal in kids and infants

85% excreted 4 DAY half life Different pathways and

metabolism than in adults More similar to non-humans

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Neurophysiological Effects. Like alcohol, we don’t know! Might block adenosine

Neuromodulator that inhibits firing So, caffeine disinhibits? High doeses block benzodiazipine

receptors

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Neurophysiological Effects Might cause release of epinephrine Causes smooth muscles to relax,

striate muscles to contract Decreases airway resistance

Good for asthma, colds Constriction of blood vessels to the

brain Dilation other places

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Neuropshysiological Effects Not sure if it helps performance

Does reduce drowsiness,boredom. Increases FA levels, could be

performance enhancing, especially for long athletic events. Controlled substance.

Increases time in light sleep Stages 1 and 2 Can counteract barbiturates.

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Effects on Nonhumans Small doses increase SMA Large doses do the opposite Increases FR responding

Affects timing Increases suppressed behaviour. Generalizes to coke, not to

amphetamine.

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But, how does that first cup make you feel? Humans are great at discriminating

1.8 mg, about a sip of coffee!! Caffeine makes us:

Energized Focused Motivated Same in non users

All at low-moderate doses (20-200 mg) About a cup of coffee.

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Could I ever use a coffee Tolerance

Sustained use leads to more adenosine receptors

Whole deal changes if big dose given to non users.

Withdrawal Headache Flu like symptoms Bad attitude in general 100 mg a day, most all of us!

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Reinforcing Properties Hard to get animals to self-

administer Will prime cocaine use Lots of variation in us

Task demands Caffeine experience.

Demand is relatively inelastic. Late 1970s, 6 bucks a pound.

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Bad Stuff Cancer? Caffeinism OD?

30-80 cups of coffee Reproduction

Chromosomal damage? Toxicity

Cardiac effects? Depends on method

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Beware the International Coffee Conspiracy!