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Drugs. Psychoactivity and Dependence Psychoactive Drug A chemical substance that alters perceptions, mood, or behavior Three common psychoactive drugs:

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Presentation on theme: "Drugs. Psychoactivity and Dependence Psychoactive Drug A chemical substance that alters perceptions, mood, or behavior Three common psychoactive drugs:"— Presentation transcript:

1 Drugs

2 Psychoactivity and Dependence

3 Psychoactive Drug A chemical substance that alters perceptions, mood, or behavior Three common psychoactive drugs: –Caffeine –Alcohol –Nicotine Induce an altered state of consciousness

4 Common Properties of Addiction Physical dependence Tolerance Withdrawal symptoms Drug rebound effect

5 Drug Abuse Recurrent drug use that results in disruption of academic, social, or occupational functioning or in legal or psychological problems

6 Dependence A state of physiological and/or psychological need to take more of a substance after continued use. Withdrawal follows if the drug is discontinued Psychological dependence although the body does not physically crave the drug, the mind does.

7 Tolerance Reduced responsiveness to a drug, prompting the user to increase the dosage to achieve effects previously obtained by lower doses of the drug The user experience neuroadaptation and thus requires more of the drug to get the effect.

8 Tolerance

9 Withdrawal The discomfort and distress that follow when a person who is dependent on a drug discontinues the use of the drug Withdrawal symptoms are usually the opposite of the drug’s effects – Drug Rebound Effect

10 Why do people abuse drugs? Biopsychosocial Theory

11 Drugs and Neurotransmission

12 Neurotransmission The process whereby neurons communicate with each other Neurotransmission, especially in the brain and spinal cord, helps explain the effects of psychoactive drugs. Psychoactive drugs interfere with normal neurotransmission.

13 Neurotransmitters Chemical messengers that cross synaptic gaps between neurons When released by the sending neuron, neurotransmitters travel across the synapse and bind to receptor sites on the receiving neuron, setting up the next link in the chain of communication.

14 Synapse The junction between the tip of the sending neuron and the receptor sites on the receiving neuron Call the synaptic gap or cleft

15 Neural Activity

16 Neurotransmitters and the Synapse

17 Reuptake Process where the unused neurotransmitter chemical is reabsorbed by the sending neuron

18 Reuptake

19 Psychoactive Drugs and Synapses Psychoactive drugs affect synapses and neurotransmitters in three ways: –Binding with receptor sites (mimics)* –Blocking receptor site –Blocking neurotransmitters’ reuptake* * Increase the likelihood of the receiving neuron firing

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21 Drug Classifications

22 Four Psychoactive Drug Categories Four different categories we will study: 1.Depressants – depress, inhibit brain activity 2.Opiates – Similar to morphine, produce feelings of euphoria & reduce pain 3.Stimulants – excite brain activity 4.Psychedelic/Hallucinogens/Marijuana – distort sensory perceptions. –Designer “Club” Drugs – “fifth category” that includes variety of psychoactive drugs.

23 Drug Classifications: Depressants

24 Depressants Drugs that reduce neural activity and slow body functioning Includes alcohol and sedatives

25 Types of Drugs: Depressants class of substances that reduce central nervous system activity and slow bodily functions and awareness alcohol –40% of US adults report that they drink alcohol –9% of US adults (14 million people) have alcohol abuse or dependence –has inhibitory effect on excitatory neurotransmitters also on inhibitory neurotransmitters (disinhibition)

26 psychological effects of alcohol –reduction of inhibitory conflict (behavior that is both strongly instigated and inhibited) –facilitates aggressive behavior (alcohol myopia: disproportionate influence of immediate experience on behavior and emotion due to alcohol use) Types of Drugs: Depressants

27 barbituates: (aka. tranquilizers) drugs that mimic the effects of alcohol by depressing nervous system activity –cause sedation and drowsiness, often used as sleep aids –can be lethal alone or especially in combination with alcohol opiates: opium and its derivatives (morphine, codeine, heroin) –can alleviate physical pain and anxiety, but highly addictive activate dopamine-based reward pathway bind to brain’s opioid receptors, leading body to produce less endorphins, leaving person craving more opiates to relieve pain Types of Drugs: Depressants

28 Depressants Alcohol—CNS depressant Barbiturates—induce sleep Tranquilizers—relieve anxiety

29 29 Continue Depressants/Sedatives Reduce or depress CNS activity –Partly by increasing activity of the inhibitory neurotransmitter GABA. (GABA Agonist) Examples –AlcoholAlcohol –Barbiturates – very addictive –Gamma Hydroxybutryrate (GHB)

30 Alcohol (ethyl alcohol) Found in beer, wine, and liquor The second most used psychoactive drug (caffeine first) Slows thinking, and impairs physical activity

31 Blood Alcohol Content (BAC) A measure of how much alcohol is in a person’s bloodstream BAC of.08 considered legal intoxication in most states

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33 What do we mean by “one drink?” One 12-ounce can of beer has about the same amount of alcohol as 4 ounces of wine or 1 ounce of whiskey

34 Euphoric Affects of Alcohol Alcohol impairs the parts of the brain responsible for controlling inhibitions and making judgments Results in less self-control and sometimes more aggressive behavior. Also depends on environment and expectations.

35 35 Return Effects of Alcohol Affects Several Neurotransmitters –Dopamine –Seratonin –GABA Enhances the Effect of Endorphins – (natural pain killers) Interacts with Dopamine Systems ( Permanent damage to ability to feel pleasure with prolonged abuse ) Affects Specific Brain Regions –Depresses activity in the locus coeruleus ( activation center for cerebral cortex – judgment, inhibitions.) –Impairs the hippocampus (memory) –Suppresses the cerebellum (coordination)

36 Alcohol, Memory, and Sleep Studies have shown that alcohol impairs memory by suppressing the processing of events into long term memory. Alcohol impairs REM sleep, further disrupting memory storage. Also impairs speech and physical functioning. Death can occur if the brain’s respiratory center can no longer function.

37 Alcohol’s Affect on the Brain Alcoholism shrinks the brain

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40 Sedatives Drugs that reduce anxiety or induce sleep Also called tranquilizers Include barbiturates and benzodiazepines

41 Barbiturates Drugs that depress the activity of the central nervous system and thereby reduce anxiety Can be lethal in overdose and interact with other drugs, especially alcohol Impair both memory and judgment Can create tolerance and physical & mental dependence Withdrawal can cause REM rebound nightmares, hallucinations, disorientation and even life-threatening convulsions.

42 Benzodiazepines/Tranquilizers Drugs that depress that activity of the central nervous system without most of the side effects associated with barbiturates Help to reduce anxiety Include Valium and Xanax Can create dependency

43 Inhalants Chemicals that are inhaled to alter consciousness. Paint, glue, gasoline, nitrous oxide & aerosol sprays. Low doses may relax and reduce inhibition High doses can cause hallucinations and loss of consciousness. Toxic to the liver and other organs.

44 Drug Classifications: Opiates

45 Opiates/Narcotics Drugs that depress neural activity, temporarily lessen pain and anxiety and produce feelings of euphoria Include: opium, morphine, and heroin

46 46 Opiates Can induce sleep and relieve pain. Depress activity in cerebral cortex Agonist for endorphins Have complex effects on consciousness. Highly addictive class of drugs. Severe physical withdrawal High overdose incidence Examples –Opium –Morphine –Heroin –OxyContin

47 Endorphins Natural, opiate-like neurotransmitters linked to pain control and to pleasure Body’s natural pain killers

48 Morphine Strong sedative and pain-relieving drug derived from opium Works by preventing pain neurons from firing or releasing pain-signaling neurotransmitters (Substance P) into the synapse

49 Other Opiates Chemically similar to morphine and have strong pain-relieving properties Mimic the brain’s endorphins Heroin, methadone Percodan, Demerol

50 Drug Classifications: Stimulants

51 Types of Drugs: Stimulants class of drugs that stimulate the central nervous system and arouse bodily functions –including caffeine, nicotine, amphetamines, cocaine, and ecstasy (MDMA) –increase heart rate and breathing, cause pupil dilation, and increase energy

52 Stimulants Drugs that excite neural activity and speed up body functions Include: caffeine, nicotine, amphetamines, and cocaine All are at least mildly addictive.

53 53 Stimulants Increase Behavioral and Mental Activity Agonists of dopamine and norepinephrine Very addictive Examples: –Amphetamines including Meth –Cocaine –Caffeine –Nicotine –MDMA (“Ecstasy”) http://www.drugfree.org/Port al/DrugIssue/MethResource s/faces/photo_11.html

54 Caffeine Stimulant found in coffee, chocolate, tea, and some soft drinks Provides user with a sense of increased energy, mental alertness, and forced wakefulness Blocks neurological receptor sites that if activated, sedate the central nervous system Withdrawal symptoms are sleepiness, fatigue, anxiety, insomnia, increased heart rate.

55 Nicotine Stimulant found in tobacco Effects similar to those of caffeine – reduces fatigue & drowsiness and increases mental alertness Affects various areas in the brain affecting mood, attention & arousal Very addictive and does not stay in the body very long See video clip on nicotine addiction.

56 Types of Drugs: Stimulants cocaine: typically sniffed, leads to a 15-30 minute euphoric rush –depletes supply of dopamine, serotonin, and norepinephrine results in a depressive crash after drug wears off

57 Cocaine Stimulant derived from leaves of the coca plant Crack – cocaine crystals Blocks the reuptake of certain neurotransmitters Dependency is quick and severe; places extreme strain on cardiovascular system Can cause cocaine psychosis – schizophrenia-like symptoms including auditory hallucinations & paranoia, “cocaine bugs” or tactile hallucinations

58 How Cocaine Works

59 Amphetamines Drugs that stimulate neural activity, speeding up body functions, with associated energy and mood changes Includes: speed, uppers, and methamphetamines Mimic adrenaline Can cause irreversible changes in mood & function by reducing dopamine receptors & transporters. Withdrawal causes fatigue, deep sleep, intense depression, increase in appetite.

60 Types of Drugs: Stimulants MDMA (methylenedioxymethamph etamine): commonly known as “ecstasy”; leads to emotional elevation and feelings of social connectedness –triggers release of dopamine and serotonin (neurotransmitters associated with pleasure, positive feelings) –even one use can permanently damage serotonin-producing neurons

61 Drug Classifications: Hallucinogens

62 Types of Drugs: Hallucinogens class of drugs that distort perceptions and can evoke sensory images (hallucinations) –include marijuana, LSD, PCP marijuana: major active ingredient is THC (chemical similar to cannabanoids: neurotransmitters involved in appetite regulation, memory, and pain) –can lead to distortions in perception, making motor tasks such as driving dangerous

63 Hallucinogens/Psychedelic Drugs Drugs that distort perceptions and evoke sensory images in the absence of sensory input Include: LSD, Mescaline and Marijuana

64 64 Hallucinogens Also called psychedelics. –Create a loss of contact with reality. –Alter other aspects of emotion, perception, and thought. Damage hippocampus Serotonin agonists Examples –LSD –Psilocybin Mushrooms –Peyote –Ketamine –Marijuana (THC)

65 Lysergic Acid Diethylamide (LSD) Powerful hallucinogenic drug Also known as “acid” The effects vary from person to person Users can be dangerous to themselves and others. Similar to neurotransmitter, serotonin. Flashbacks, psychotic reactions can occur.

66 Hallucinogen Affect Hallucination - like patterns Geometric forms, similar to those experienced by drug users during drug - induced hallucinations, can be seen in the embroidery of the Huichol. These Mexican Indians used peyote, from which the hallucinogen mescaline derives.

67 Marijuana Leaves, stems, resin, and flowers form the hemp plant When smoked, lower inhibitions and produce feelings of relaxation and mild euphoria THC (delta-9-tetrahydrocannabinol) is the active ingredient. Receptors in the brain for anandamide also accept THC Disrupts memory; lung damage from smoke Withdrawal may cause insomnia, tremors and decreased appetite. Is helpful in decreasing nausea and reducing effects of glaucoma.

68 “Club” Drugs Ecstasy (MDMA)—feelings of euphoria, increased well-being. Side effects—dehydration, hyperthermia, tremor, rapid heartbeat

69 Ecstasy Hallucinogenic drug that produces lower inhibitions, pleasant feelings, and greater acceptance of others Also called MDMA Blocks serotonin reuptake prolonging its “good” feeling Even moderate users may experience permanent brain damage to serotonin nerve endings & even memory and verbal reasoning problems up to a year later. Dehydration, rapid heartbeat, tremors, muscle tension, teeth clenching & high body temp can result.

70 Other “Club” Drugs: Dissociative Anesthetics Dissociative anesthetics—include PCP and Ketamine. Deaden pain, produce stupor or coma, may induce hallucinations Create feelings of dissociation & depersonalization PCP or angel dust, ketamine Effects of “trips” differ for each person Can result in hyperthermia (high body temp), convulsions & death. Affects neurotransmitter glutamate causing a release of more dopamine in the brain. Highly addictive. Long term effects can be memory loss and depression.

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72 Prevention

73 High School Drug Use (Johnston & others, 2002)

74 Near Death Experiences altered state of consciousness reported after a close brush with death –usually experienced after person has been declared clinically dead 12-40% of those who have come close to death recall NDEs (Gallup, 1982; Van Lommel et al., 2001) –sometimes interpreted as a window to the afterlife (consciousness without brain activity?)

75 Near Death Experiences typical progression of NDE (Mauro, 1992; Morse & Perry, 1992): –unpleasant/uncomfortable sound (buzzing, ringing) –experience of pleasant emotions (calmness) –out-of-body experience –moving toward bright light, through long tunnel –meeting the dead, religious figures, etc. –encountering a “being of light” life review –reunified with body (often reluctantly)

76 NDEs & Other Altered States descriptions of NDEs, hallucinogenic experiences very similar –recalling old memories, out-of-body sensations, visions of tunnels and bright lights NDEs also similar to those suffering temporal lobe seizures –case of electrically stimulating temporal lobe = sensations of floating and seeing self from above (Blanke et al., 2002, 2004)

77 NDEs & Other Altered States oxygen deprivation can produce hallucinations, tunnel vision (Woerlee, 2004) –deactivation of inhibitory cells = increased visual cortex activity, resulting in growing patch of light (Blackmore, 1993) Siegel (1980): NDEs are “hallucinatory activity of the brain” –differences between NDEs and hallucinations?

78 Kinseher (2006): experience of impending death is a completely novel one for the mind –brain scans memory bank for comparable information (“seeing life flash before your eyes”) –out-of-body experiences created by mind, like dreams (unusual synthesis of sensory input and top-down processing) Why Do NDEs Happen?


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