Transcript Chapter 15
PRINCIPLES OF DRUG
ACTION
Outline
1. The Drug Problem
2. Drug Tolerance & Withdrawal
3. Role of Learning in Drug Tolerance
and Withdrawal
a. Contingent Drug Tolerance
b. Conditioned Drug Tolerance
c. Conditioned Withdrawal
Which drugs are most
addictive?
Two sets of standards
Legal standards
Set by the Controlled Substances Act of 1970
Five different schedules of drugs
Note that alcohol and nicotine are not on the drug
schedule
Can be bought without prescription
Scientific standards
Reflected by expert views of addictive potential
Two experts rated
abuse potential of
various drugs
Jack Henningfield,
formerly Chief of Clinical
Pharmacology at the
Addiction Research
Center at NIDA
Neil Benowitz, addiction
researcher at University
of California at San
Francisco
1) presence and severity
of withdrawal
2) how reinforcing the
drug is (from human and
animal studies)
3) the degree of tolerance
produced by the drugs
4) degree of dependence
Difficulty quitting
Relapse
5) degree of intoxication
Overall rankings
Heroin (1.9)
Alcohol (2.5)
Cocaine (2.65)
Nicotine (3.35)
Caffeine (5.0)
Marijuana (5.4)
Two of the top 4 substances
are legal
Marijuana is lowest on this
list, but a schedule 1 drug.
Keep in mind long term
consequences were not
included.
Note that low numbers
indicate the most
serious abuse potential
Also note how closely
the two experts rated
the drugs on the
various measures
Physical dependence
Psychological dependence
What does it mean to be addicted?
American Psychiatric Association has
stopped using the term addiction and
addict in their professional writing
Due to bad connotation
They use the term substance related
disorders
Two general disorders
Substance Dependence (more severe)
Substance Abuse
Note that merely using a drug, even if it
is illegal, does not necessarily indicate a
substance related disorder
The use must be maladaptive
Contingent Drug Tolerance
Ethanol-before group
received an ethanol injection once every 48 hours
Ethanol is an anticonvulsant
repeatedly experience this effect
Ethanol-after group
received ethanol injections on the same bi-daily schedule
1 hour before a convulsive amygdala stimulation
1 hour after each convulsive stimulation
Never experience ethanol's anticonvulsant effect
Test
only the rats in the ethanol-before-stimulation group
were tolerant to alcohol's anticonvulsant effect
Crowell, Hinson, and Siegel
(1981)
Two groups of rats
Manipulation of context
20 alcohol injections
20 saline injections
alternating sequence
one every 48 hours.
alcohol in context 1 (test room)
saline in context 2 (colony room)
Tolerance only occurred when the subjects were tested in the
same environment in which they had previously received alcohol