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
• 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)
Types of Drugs: Depressants
• 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
Depressants
• Alcohol—CNS depressant
• Barbiturates—induce sleep
• Tranquilizers—relieve anxiety
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)
Continue
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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.
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)
Return
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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
Opiates
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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
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Opium
Morphine
Heroin
OxyContin
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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.
Stimulants
• Increase Behavioral and
Mental Activity
• Agonists of dopamine and
norepinephrine
• Very addictive
• Examples:
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Amphetamines including Meth
Cocaine
Caffeine
Nicotine
MDMA (“Ecstasy”)
http://www.drugfree.org/Port
al/DrugIssue/MethResource
s/faces/photo_11.html
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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
(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
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
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)
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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 (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?
Why Do NDEs Happen?
• 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)