PSY 250 Lecture Notes - Lecture 18: Methadone, Birth Weight, Time Perception
Chapter 5 Drugs, Addiction, and Reward
- Honore de Balzac was an author who used stimulant drugs to keep him awake so he
could write as much as possible (45 novels in 20 years), but he died at age 51 because the
overuse of drugs causing a heart condition
- Psychoactive Drugs
- Drug: a substance that on entering the body changes the body or its functioning
- Two classes of drugs
- Agonist: mimics or enhances the effect of a neurotransmitter
- Antagonist: may occupy the receptors without activating them,
simultaneously blocking the transmitter from binding to the receptors
- Psychoactive Drugs: drugs that have psychological effects, such as anxiety relief
or hallucinations
- Effects of abused drugs vary
- Example: arouse or relax; expand the consciousness or dull the senses
- Addictive drugs produce pleasure and other similar effects
- Addiction: identified by preoccupation with obtaining a drug, compulsive use of
the drug inspire of adverse consequences, and a high tendency to relapse after
quitting (produce withdrawal)
- Withdrawal: a negative reaction that occurs when drug use is stopped
- Withdrawal symptoms are caused by the nervous system having adapted to the
drug’s effects
- Example: relaxation, constipation, chills, and positive mood caused by
heroin is replaced by agitation, diarrhea, fever, and depression during
withdrawal
- Tolerance: the individual becomes less responsive to the drug and required
increasing amounts of the drug to produce the same results
- Results from adaptation to the drug and requires more for a better “high”
- Opiates
- Opiates: drugs derived from the opium poppy
- Effects of opiates
- Analgesic (pain relieving)
- Hypnotic (sleep inducing)
- Euphoria (sense of happiness or ecstasy)
- Addictive
- Uses of opiates
- Originally eaten (4000 BCE)
- Pipe smoking with the American Indians
- Morphine extracted in early 1800s (surgery, battle wounds, cancer)
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- Heroin: synthesized from morphine (used to be marketed by the Bayer
Drug Company of Germany as an over the counter analgesic until its
dangers were recognized)
- Illegal in US
- Still used in some European countries as a drug replacement
treatment in addiction centers
- Codeine (cough suppressant)
- Opioids: synthetic drugs that have replaced opiates (OxyContin)
- Heroin is the most notoriously abused opiate and passes through the
blood-brain barrier easily; rapid effect increases addictive potential; major
danger is overdose; heroin addiction might be a lifelong addiction
- Buying heroin as a normal dose in a different neighborhood can cause
overdose
- Example: an amount of heroin that killed 32% of rats injected in
their customary drug-taking environment killed 64% of rats
injected in a novel environment
- Candace Pert discovered why opioid drugs are so effective as pain
relievers
- Endorphins (endogenous opioids): generated within the body; pain relief
- Depressants
- Drugs that reduce central nervous system activity
- Sedative (calming) drugs, anxiolytic (anxiety-reducing) drugs, and
hypnotic drugs
- Alcohol
- Ethanol; drug fermented from fruits, grains, and other plant
products
- It acts at many brain site to produce euphoria, anxiety reduction,
sedation, motor incoordination, and cognitive impairment
- Oldest abused drugs
- Low doses = turns off the inhibition the cortex normally exerts
over behavior, resulting in behavioral stimulation, but it also has a
direct stimulatory effect by increasing dopamine release
- High doses = sedative or hypnotic effect; behavior moves from
relaxation to sleep or unconsciousness
- Eventually metabolizes and becomes a stimulant again (may help
you fall asleep but only to be found awaken in the middle of the
night)
- Involved in ⅓ of all US traffic fatalities
- Blood alcohol level in the US 0.08%
- Effects of long term abuse
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- Brain stem shutdown (coma or death); cirrhosis of liver;
vitamin B1 deficient; brain damage; Korsakoff’s syndrome;
memory loss; sensory and motor impairment
- Binge drinkers are more impulsive and have learning and
memory impairments
- 5th leading cause of premature death and disability
- Withdrawal symptoms
- Tremors, anxiety, mood and sleep disturbances
- Delirium Tremens: hallucinations, delusions, confusion,
and, in extreme cases, seizures and possible death
- Increases release of GABA
- Gamma-Aminobutyric Acid (GABA): the most prevalent
inhibitory neurotransmitter
- GABA and glutamate combined creates sedation, anxiety
reduction, muscle relaxation, and inhibition of cognitive and motor
skills
- Affects opiate receptors (increases dopamine release), serotonin
receptors, and cannabinoid receptors
- Fetal alcohol syndrome (alcohol passes easily through the
placenta)
- Barbiturates and Benzodiazepines
- Barbiturates: in small amounts act selectively on higher cortical
centers, especially those involved in inhibiting behavior; in low
doses, they produce talkativeness and increased social interaction,
and in higher doses, they are sedatives and hypnotics
- Treat insomnia
- Prevent epileptic seizures
- 1912-1960 treated anxiety and insomnia
- Not addictive in prescribed doses, but can create tolerance
and increased dosages which leads to addictive symptoms
- Benzodiazepines: act at the benzodiazepine receptor on the GABA
complex to produce anxiety reduction, sedation, and muscle
relaxation
- Reduce anxiety by suppressing activity in the limbic system
- Effects in the brain stem produces relaxation
- GABA activation in the cortex and hippocampus results in
confusion and amnesia
- Valium (diazepam), xanax (alprazolam), halcion
(triazolam), rohypnol (roofies or rophies; date rape drug)
- Stimulants
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Document Summary
Drug: a substance that on entering the body changes the body or its functioning. Agonist: mimics or enhances the effect of a neurotransmitter. Antagonist: may occupy receptors without activating the them, simultaneously blocking the transmitter from binding to the receptors. Psychoactive drugs: drugs that have psychological effects, such as anxiety relief or hallucinations. Example: arouse or relax; expand the consciousness or dull the senses. Addictive drugs produce pleasure and other similar effects. Addiction: identified by preoccupation with obtaining a drug, compulsive use of the drug inspire of adverse consequences, and a high tendency to relapse after quitting (produce withdrawal) Withdrawal: a negative reaction that occurs when drug use is stopped. Withdrawal symptoms are caused by the nervous system having adapted to the drug"s effects. Example: relaxation, constipation, chills, and positive mood caused by heroin is replaced by agitation, diarrhea, fever, and depression during withdrawal.
