Psychoactive 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
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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
Tolerance
• Reduced responsiveness to a drug,
prompting the user to increase the
dosage to achieve effects previously
obtained by lower doses of the drug
Tolerance
Withdrawal
• The discomfort and distress that follow
when a person who is dependent on a
drug discontinues the use of the drug
• Drug Rebound Effect -Withdrawal
symptoms are usually the opposite of
the drug’s effects
– “For every action there is an equal and opposite
reaction”
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
Depressants
• Alcohol—CNS depressant
• Barbiturates—induce sleep
• Tranquilizers—relieve anxiety
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.
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
(Phenobarbital)
• 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.
Addiction and Depressants
• Play “Depressants and Their Addictive
Effect on the Brain” (4:24) Segment #22
from The Mind: Psychology Teaching
Modules (2nd edition).
• How does withdrawal occur?
• What’s happening to the neurons of an
addict?
• How are these drugs suppressing the
nervous system?
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
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
Stimulants
• Drugs that excite neural activity and
speed up body functions
• Include: caffeine, nicotine,
amphetamines, and cocaine
• All are at least mildly addictive.
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.
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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
– See the story of Len Bias (4 min)
• 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.
The Faces Of Meth
http://www.anti-meth.org/photos2.html
Drug Classifications:
Hallucinogens
Hallucinogens/Psychedelic Drugs
• Drugs that distort perceptions and evoke
sensory images in the absence of
sensory input
• Include: LSD, Mescaline and Marijuana
Lysergic Acid Diethylamide (LSD)
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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
• 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
Drug Use
(2007 National Survey on Drug Use and Health)
Treatment
• Play “Treating Drug Addiction: A Behavioral
Approach” (19:40) Segment #30 from The
Mind: Psychology Teaching Modules (2nd
edition). Watch if time allows.
• What become “triggers” for addicts?
• How do addicts’ bodies react to “triggers?”
• Describe how this treatment works.
• Describe what withdrawal/addiction is like?
• What do brain scans show about addicts’
brains?