Transcript drugs
drugs Controversy, danger, tradition Controversy and confusion • Uneasy boundary between legal and illegal, beneficial and harmful • Many legal drugs injure in high amounts • Many are addictive • Many illegal drugs have medical uses • Gateway drugs? • Misinformation – often causes people to ignore real risks background • Humans use, and abuse, a wide variety of drugs which exert widely ranging effects • Genetics play a role in our differing sensitivities to drugs • Also, behavioral tendencies like impulsivity, novelty-seeking, hyperactivity, and variations in tolerance of stress, are important Focus on the brain • The release of dopamine and the pleasure which follows, tells us what we like • This nudges us into eating, drinking, and other beneficial behaviors • Years of research has revealed that ingesting many drugs also causes dopamine to be released, hi-jacking this natural reward system - to our peril Underlying neurology • The dopamine circuit begins in the ventral tegmental area (found at the top of the brain stem) which synthesizes dopamine which it passes to the • Nucleus accumbens which then connects through its axons to areas of the frontal lobes • Continued use of some drugs (opiates) causes neurons to shrink or otherwise work less effectively, forcing the user to rely on the drug for pleasure but there is more • Two other key brain structures are also involved • The amygdala adds an emotional overtone to the desire for this manipulation of the reward circuit • Even more importantly, the hippocampus makes sure that we remember the fun times associated with the drug, and the surroundings which accompany it perspectives • Many drugs decrease our ability to experience pleasure normally • We then need them to make-up for what they have taken from us • But these changes to our natural reward system can also be effected by other things such as gambling, video games, even sweets alcohol • World-wide and ancient use • Part of many of our customs and traditions • At the most basic level, simply a class of molecules • We are concerned with ethanol – the type which people drink Alcohol – the depressant that makes us act out • While we typically link drinking alcohol with wild, reckless behavior, it is actually a depressant • That’s because it, especially in high amounts, lessens our inhibitions by turning off our frontal lobes, increasing impulsivity/risk- taking behavior • Excessive use leads to physical damage tranquilizers • Another type of depressant • Help us relax, fall asleep and decrease muscle tension • Barbiturates formerly commonly prescribed, now out of favor – addiction and other risks • Benzodiazepines, such as valium, now hold sway – less addictive bennies • Great danger mixing them with alcohol • Both stimulate production of the neurotransmitter GABA, which can inhibit the function of the medulla disrupting our breathing and heartbeat – a truly fatal mix • Another aspect of these drugs is their use as “date rape” drugs – very inconspicuous • Flunitrazepam/Rohypnol, or “roofies” • Induce euphoria, lack of inhibitions, amnesia narcotics • Produce drowsiness, insensitivity to pain and indifference to events • Most commonly opiates • Natural substances derived from the opium poppy • Also synthetic compounds with similar chemical structures - methadone Opiates - why they wreak such havoc • Give users a warm, happy, contented feeling • Heroin, morphine, methadone (synthetic) • Virtually eliminate pain and anxiety but at the cost of apathy and fast addiction • When the unnatural production of dopamine ceases the body cries out for it • If denied, chemical withdrawal begins Withdrawal from opiates • During withdrawal all of the pleasant effects of the drug are reversed • While before there was contentment now there is anxiety, before happiness now pain • Worse yet, we need more - tolerance • Need for a “fix” causes desperate actions • theft, burglary, prostitution, shattered lives, criminal prosecution Long term effects • Longitudinal studies paint a very bleak picture • Of 581 users followed from 1962, nearly half were dead by 1997 • Survivors self-medicated, including cigarettes (67%) • They also faced many health problems, including hypertension, liver and lung ills, etc. stimulants • Drugs which boost energy, alertness, activity and pleasant feelings • Caffeine perhaps the most widely used drug? – 90%! • Delivered through coffee, chocolate, soda, energy drinks, tea • Can lead to dependency – headaches and drowsiness if denied cocaine • The drug of choice in the 80’s and beyond • Derived from the leaves of the coca plant • Creates a euphoric sense of happiness and increased activity • Considered a stimulant because it turns off inhibitors, leading to an increase in behaviors • But its use decreases over-all brain activity More cocaine • Very powerful, with many effects • Works by preventing a terminal button’s synaptic vesicles from reabsorbing dopamine (reuptake) thus increasing its effects • Also, kicks up norepinephrine and serotonin levels • Works as an anesthetic ( as does lidocaine and Novocain) by stopping action potentials Cocaine and addiction • Usually taken in powder form with euphoria coming on within minutes and lasting for up to an hour • If smoked through free basing, its effects emerge even faster • The faster the pleasure, the quicker the addiction Crack – addiction squared • Crack cocaine, first developed in the mid80’s, provides even quicker, virtually instantaneous, pleasure • Addictive after only a few uses • Very expensive, readily addictive and quick to lose its effects • It takes over lives, ruining careers and families Long term • While coke-triggered heart attacks and strokes strike occasionally, its residual damage is harder to assess • Many who started to use it in the 80’s are now well into their 50’s and the number of addicts over 50 is set to explode, perhaps to over 4 million • Effects are often worsened by overall neglect marijuana • CONTROVERSY • Intensifies sensory experiences, induces euphoria, distorts time perception, also can lead to feelings of anxiety • Formally known as Cannabis sativa • Main psychoactive chemical is called THC • Cultivated for at least 3000 years The neurochemistry of marijuana • Mimics a neurotransmitter called anandamide • They attach to receptors which affect short term memory (on the hippocampus) which can make it difficult to remember events and learn • Also they impact our muscle coordination by altering the normal functions of the cerebellum Medical benefits • Research shows that marijuana aids some medical conditions: Chemotherapy problems – decreases vomiting, nausea, and anxiety Aids-related wasting – improves appetite Pain and muscle spasms – decreases these plus depression Glaucoma – decreases pressure on eye Why pot? • It is so easy to administer • Puff by puff, the user can simply stop when acceptable levels have been reached • Low toxicity • Plus, its effects last no longer than 2 – 3 hours and no chance of overdose • But, since it is fat soluble, it can be detected for 28-30 days after ingestion The debate • • • • Life threatening? Harmless? Probably neither. A gateway drug? (millions spent) very few move on to cocaine or heroin most used tobacco and alcohol first if marijuana disappeared would cocaine and heroin? withdrawal • Is pot addictive? tolerance doesn’t seem to develop nothing compared to opiates, alcohol, or nicotine very little proof of any residual effects 99% discontinue use without any withdrawal effects A real danger? • Amotivational syndrome • Putting off important things till tomorrow because you got high today • Coupled with well established barriers to learning, pot smoking can cause people to waste a lot of time and money • Fact of fiction? Long term • A 2003 study stated that even among regular users there is no proof of irreversible cognitive damage • Uncertain as to long range pulmonary disease and cancers though pot does contain carcinogens hallucinogens • Drugs which induce sensory distortions • Can come from plants – mushrooms (psilocybin) or cactus (peyote) • Also produced synthetically – LSD • Famous for amazing intensification of sensations and experiences – from dreamlike states to transcendent mystical events Mescaline and psilocybin • Mescaline, better known as peyote, is derived from a Chihuahan cactus found in Texas and Mexico • It has been used medicinally and sacramentally for thousands of years • US government allows its use in Native American religions • Initial focus of Carlos Castenada’s “quest” More peyote • Users consume it in buttons • Many initially experience nausea which is followed by feelings of physical energy (small doses) or visionary experiences which they view as a spiritual and physical blessing • A recent study of regular Native American users found no harmful cognitive or psychological effects, and some gains! Magic mushrooms • Psilocybin, an active chemical compound in hundreds of mushrooms that causes hallucinogenic experiences • Used world-wide especially by the Aztecs • Can be smoked or simply eaten • Castenada, and many others, sampled • Most common natural hallucinogenic lsd • Officially lysergic acid diethylamide • Accidentally discovered by a Swiss chemist, Albert Hoffman, in 1943 • Somehow ingesting it, he experienced an amazing shift in consciousness • “An uninterrupted stream of fantastic images of extraordinary vividness and plasticity” passed before his eyes “ accompanied by an intense kaleidoscopic play of colors” Further “research” • Hoffman went on to try LSD on many more occasions • These experiences were invariably pleasant except once, when tired, he mixed it with amphetamines and experienced history’s first “bad trip” • Recently turned 100, he still considers LSD “medicine for the soul” Then things got weird • The word slowly spread until in the early 60’s it reached Timothy Leary, a maverick Harvard psychologist with extensive work with psilocybin • Leary experimented with his graduate students and raved about LSD’s effects reporting profound mystical and spiritual experiences • “Turn on. Tune in. Drop out.” • “The most dangerous man in America.”? The serotonin connection • LSD attaches to receptors usually used by serotonin • It apparently stimulates the receptors in strange ways • Change our typical perceptual filtering? • Bad trips largely arise from the setting • In secure environments, very unlikely • Some suffer flashbacks, but still rare ecstasy • Also known as MDA or MDMA • Synthetic compounds which resemble neurotransmitters and stimulate serotonin receptors • Users report heightened intimacy and insight into relationships • Many negative effects – confusion, anxiety • Evidence points towards damage to axons devoted to serotonin Crystal meth • Also known as methamphetamine • Causes extensive production of dopamine • Ingestion leads to an almost instant tingly rush of sexiness, confidence and alertness • But eventually, dopamine receptors are depleted and users feel unable to experience pleasure without more and more A hurricane of shattered bodies and lives • Addiction often follows with devastated families, lost jobs, ruined health, crime, etc • Horrible physical aftermath – premature aging, skin sores, ruined teeth, wasting • Burns victims overwhelm rural counties $$ • But for the Bush administration pot is still enemy #1 – Local governments disagree