Drugs & Behaviour PDF

Dr. Michelle St. Pierre, R. Psych. Drugs & Behaviour  Alcohol Source of Alcohol Fermentation Sugar is dissolved in water and left exposed to the air Yeasts Ethanol and Carbon Dioxide 10-15% Distillation 40-50% Alcohol lower boi...

Dr. Michelle St. Pierre, R. Psych. Drugs & Behaviour  Alcohol Source of Alcohol Fermentation Sugar is dissolved in water and left exposed to the air Yeasts Ethanol and Carbon Dioxide 10-15% Distillation 40-50% Alcohol lower boiling point vs water  Measurement of Alcohol In the United States, a proof spirit (100 proof) is one containing 50 percent alcohol by volume Thus, the U.S. proof number is twice the percentage of alcohol by volume. Typically, the proof is printed on the label. Canada and other countries – alcohol by volume (ABV)  Origin and History Use from before recorded history Most cultures drink alcohol regularly The first alcohol that humans consumed was probably in the form of fermented honey or fruit. Deliberate fermentation probably began with the development of agriculture.  Origin and History Egyptian Book of the Dead (about 3000 B.C.) – beer Distillation – China 3000B.C. Greeks and Romans (lead poisoning)  Origin and History Early British and American Experience Usquebaugh = whiskey (1500s) An Inquiry into the Effects of Ardent Spirits (1785) American Prohibition Temperance Movement Eighteenth Amendment (1917) — Prohibition Enacted Twenty-First Amendment (1933) — Prohibition Repealed Yearly Alcohol Consumption Current U.S. Levels Peaked in 1979  Alcohol Yearly alcohol consumption, in gallons per person, of raw alcohol from 1850 to 1990 in the United States (2018 = 2.35) Alcohol  Measuring Alcohol Levels Blood Alcohol Level (BAL) Concentration of alcohol in whole blood Metric Measurements and Percent BAL = milligrams (mg) of alcohol per 100 milliliters (ml) of blood Conversion = moving the decimal point three places BAL of 80 mg per 100 ml (or 80 mg/dl) is the same as 0.08 percent Excreted from lungs at known rate (breathalyzer)  ROA & Pharmacokinetics Theoretical time course for BAL after taking a single drink. A: Absorption Phase B & C: Plateau Phase D: Excretion Phase  Absorption Orally - absorption in digestive tract First pass metabolism in stomach Faster on empty stomach – direct to small intestine Gender difference in first pass metabolism Females – less alcohol dehydrogenase Concentration contributes to speed of absorption 40% most rapid Higher slows stomach Carbonation  Alcohol Distribution Sex differences Age Distributed throughout body Crosses blood-brain & placental barrier  Excretion Small percentage eliminated Breath, Sweat, Tears, Urine, and Feces 90% metabolized by the liver Metabolism of Alcohol Rate-limiting step (1st step) – dependent on alcohol dehydrogenase Acetaldehyde Converted into acetyl-coenzyme (2nd step) Energy, water & carbon dioxide Individual differences Drinking experience and food can affect metabolism Microsomal ethanol-oxidizing system (MEOS) Alternate metabolizing system – Hyperactive among heavy drinkers Barbiturates  Neuropharmacology Complex & mysterious Nonspecific Receptor Sites May interact with an alcohol-sensitive area on the receptor Enter and block the ion channels Glutamate - NMDA Receptor inhibition Upregulation – hypersensitization – seizures/withdrawal GABA-Receptor excitation– enhanced inhibition Ultimately downregulation Alcohol Antagonists Naltrexone Caffeine?  Effects of Alcohol Effects on the Body Dilation of blood vessels in the skin Makes skin feel warm Loss of body water (frequent urination) Effects on Sleep Induces sleep Decreases time it takes to go to sleep Depresses REM sleep rebound Cessation leads to disturbances in sleep patterns – long term  Effects on Behaviour Low dose = stimulation > talking & higher pitch excitement & elation High dose = sedation Anger & depression Perception