Drugs

Psychoactivity and Dependence

Psychoactive Drug

• A chemical substance that alters perceptions, mood, or behavior

• Three common psychoactive drugs:

– Caffeine

– Alcohol

– Nicotine

• Induce an altered state of consciousness

Common Properties of Addiction

• Physical dependence

• Tolerance

• Withdrawal symptoms

• Drug rebound effect

Drug Abuse

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

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.

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.

Tolerance

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

Why do people abuse drugs?Biopsychosocial Theory

Drugs and Neurotransmission

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.

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.

Synapse

• The junction between the tip of the sending neuron and the receptor sites on the receiving neuron

• Call the synaptic gap or cleft

Neural Activity

Neurotransmitters and the Synapse

Reuptake

• Process where the unused neurotransmitter chemical is reabsorbed by the sending neuron

Reuptake

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

Drug Classifications

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.

Drug Classifications: Depressants

Depressants

• Drugs that reduce neural activity and slow body functioning

• Includes alcohol and sedatives

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)

• 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

• 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

Depressants

• Alcohol—CNS depressant

• Barbiturates—induce sleep

• Tranquilizers—relieve anxiety

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Depressants/Sedatives

• Reduce or depress CNS activity– Partly by increasing activity

of the inhibitory neurotransmitter GABA. (GABA Agonist)

• Examples– Alcohol – Barbiturates – very addictive– Gamma Hydroxybutryrate

(GHB)

Alcohol (ethyl alcohol)

• Found in beer, wine, and liquor

• The second most used psychoactive drug (caffeine first)

• Slows thinking, and impairs physical activity

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

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

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.

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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)

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.

Alcohol’s Affect on the Brain

Alcoholism shrinks the brain

Sedatives

• Drugs that reduce anxiety or induce sleep

• Also called tranquilizers

• Include barbiturates and benzodiazepines

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.

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

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.

Drug Classifications: Opiates

Opiates/Narcotics

• Drugs that depress neural activity, temporarily lessen pain and anxiety and produce feelings of euphoria

• Include: opium, morphine, and heroin

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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

Endorphins

• Natural, opiate-like neurotransmitters linked to pain control and to pleasure

• Body’s natural pain killers

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

Other Opiates

Chemically similar to morphine and have strong pain-relieving properties

• Mimic the brain’s endorphins

• Heroin, methadone

• Percodan, Demerol

Drug Classifications: Stimulants

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

Stimulants

• Drugs that excite neural activity and speed up body functions

• Include: caffeine, nicotine, amphetamines, and cocaine

• All are at least mildly addictive.

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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/Portal/DrugIssue/MethResources/faces/photo_11.html

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.

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.

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

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

How Cocaine Works

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.

Types of Drugs: Stimulants• MDMA

(methylenedioxymethamphetamine): 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

Drug Classifications: Hallucinogens

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

Hallucinogens/Psychedelic Drugs

• Drugs that distort perceptions and evoke sensory images in the absence of sensory input

• Include: LSD, Mescaline and Marijuana

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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)

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.

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.

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.

“Club” Drugs

• Ecstasy (MDMA)—feelings of euphoria, increased well-being.

• Side effects—dehydration, hyperthermia, tremor, rapid heartbeat

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.

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.

Prevention

High School Drug Use(Johnston & others, 2002)

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?)

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)

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)

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?

• 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?