What are Psychoactive drugs? ____________________________________________________________________________________

PSYCHOACTIVE DRUGS

There are several classes of psychoactive drugs:

I. Sedative hypnotics and antianxiety drugs

Most common are: 1. _______ (everything that

contains ethyl alcohol).

2. _______________ (ex.,

pentobarbital).

3. ________________ (ex.,

valium, librium).

- they are also known as “_________________”.

substances that influence subjective experience and behavior by acting on the nervous system.

Alcohol

Barbiturates

Benzodiazepines

mild tranquilizers

Behavioral effects:

Characteristics of sedative-hypnotic drugs:

Tolerance: ______________________________________________________________________________________________________________________________________

decreased susceptibility to a drug that develops as a result of repeated exposure to the drug; compensatory mechanisms opposite to the initial drug effect Cross-tolerance: __________________________

_________________________________________

__________________________________

tolerance that develops to one

drug carries over to other drugs suggesting that

they act through the same target.

Target of sedative-hypnotic & antianxiety drugs:

_______________________________________GABA receptors (especially GABAA subtype)

II. Antipsychotic drugs: _____________________________________________________________

Most common are: 1. _________________ (ex.,chlorpromazine - Thorazine)2. ________________ (ex.,haloperidol - Haldol)

- they are also known as “__________________”One mechanism of action: ___________________________________________________

used to treat psychoticconditions such as schizophrenia, paranoia, etc.

Phenothiazines

Butyrophenones

major tranquilizersblock dopamine

receptors, particularly the D2 subtype.

The devastating effects of schizophrenia

. . . and the hope given by antipsychotics

III. Antidepressant drugs: __________________________________________Most common are:1. ______________________________ (MAOI)2. ________________ (ex., imipramine - Tofranil)3. __________________________________ (SSRIs

ex., fluoxetine - Prozac)Mechanisms of action:- MAOIs block the breakdown of ____________(especially _______________________________)- Tricyclics and SSRIs block ___________________________ (especially _____________________)

used to treat depressive illnesses

Monoamine oxidase inhibitorsTricyclicsSerotonin-specific reuptake inhibitors

monoaminesserotonin [5-HT] and noradrenaline

the reuptake of monoamines noradrenaline and 5-HT

IV. Opiates (analgesics): ________________________________________- high potential for addiction (see next section)Most common are:1. ______________________ (morphine, codeine)2. _____________________ (heroin)3. _____________________: made in the body =endorphins (enkephalins, dynorphin)

Mechanism of action: all work by binding _______________ in the nervous system (___, ____, and_______ subtypes of opiate receptors)

V. Stimulants: __________________________________________________

Several classes of stimulants:1. _____________________ (ex., cocaine, “crack”,amphetamine)

2. __________________ (ex., pentylenetetrazol)3. ________________________ (ex., caffeine)4. ____________________ (ex., lysergic aciddiethylamide [LSD], mescaline, marijuana, psilocybin [from some mushroom])Varied mechanisms of action.

clinically employed in the treatment of pain

Opium poppy derivativesDerivatives of morphineEndogenous morphine

opiate receptors mu delta kappa

in general, increase activity of the nervous system

Behavioral stimulants

Convulsant stimulantsGeneral stimulantsPsychedelic drugs

WHAT IS DRUG ADDICTION (DEPENDENCE)

Substance Abuse:_____________________________________________________________________________

Drug Dependence (Addiction): ___________________________________________________________________________________

Important concepts:1. Drug tolerance: _______________________________________________________________________________________________________________________________________- _________________: reduced sensitivity to a drug that results from the increased ability of the body to metabolize the drug- _______________: a change that takes place innerve cells in which the activity of neuronsadjust to the excitatory or inhibitory effects of adrug (ex., receptor downregulation)- _______________: behavior change acquired through associative learning

decreased susceptibility to a drug that develops as a result of repeated exposure to a drug; compensatory mechanisms opposite to initial drug effectmetabolic tolerance

cellular tolerance

learned tolerance

pattern of drug use in which chronic and excessive intake takes a central place in ones life.

advanced state of abuse in which physical and psychological dependence have developed.

Example of tolerance to some drug actions

2. Sensitization: ____________________________________________________- for example, the behavioral activity of animals in responseto repeated injections of amphetamine increases over time.

increased behavioral response to the same dose of a drug

3. Physical dependence: ___________________ _______________________________________________________________

state in which discontinuation of drug taking will induce withdrawal syndrome

Psychological dependence is the most importantfactor in addictive behavior - produces“compulsive” drug taking behavior

Withdrawal syndrome: ______________________________________________________________________________________________

- physical dependence was originally thought tobe responsible for addictive behavior

- however, if true, treating addicts until physicalwithdrawal is over should treat addiction; itdoes not

illness induced by the elimination or absence from the body of a drug on which a person is physically dependent

Learning, through associative conditioning,produce ______________________________- associative learning= ______________________:______________________________________________________________;

- if high drug dose taken somewhere else, can belethal

Siegel injected morphine in rats for several daysin a very distinct environment- on the last day he compared the lethal effects ofa large dose of morphine in animals placed inthe same distinct context where they had received prior morphine injections or in acontext where they had not received morphine

- many rats receiving morphine in the newcontext did not survive the higher dose.

- produces ___________________________:_____________________________________________________________________

- if eliminate cues associated with drug, canreduce addiction (ex., Vietman vets.)

psychological dependence (Siegel)conditioned drug tolerance

only places and cues associated with drug taking will produce tolerance

conditioned withdrawal effects - places and cues associated with drug can also produce withdrawal symptoms

THEORY of ADDICTION

Believed to develop in stages:1. Seeking the sensation of pleasure from drug

taking;2. Pleasure is linked to mental representations

(cues) associated with drug taking;3. Cues associated with drug taking cues become

incentives, through sensitization process.

Substance abuse progresses such that ______________ of drugs are required to produce apleasurable effect, and are eventually incapableof producing pleasurable feelings.So why do people keep taking these substances?Theory of ___________________: ________________________________________________________________________________________________________________________________________

- greatly increases the “wanting” for a drug even if the “liking” is reduced.

increasingdoses

incentive-sensitization cues associated with drug taking become “attached” with motivational properties, which become “sensitized” (increase) with repeated drug taking.

Investigating craving . . .

The brain and rewarding processes

Reinforcement: ____________________________________________________________________ __________________________________________________________- important factor in producing addiction

Addictive drugs have reinforcing effects:- they activate reinforcement mechanisms- reinforcement strengthens behavior justpreceding it

Discovery of Reinforcing Brain Stimulation:(Olds & Milner, 1954) Classic study

Electrodes implantedin medial forebrainbundle (MFB)

- rats found to pressa lever thousandsof times an hourto receiveelectrical stimulation

reinforcement is the process by which there is an increase in the likelihood of occurrence of most recent behavior preceding the reinforcement

Neural System of Reinforcement_________________involved in reinforcement- system starts in a collection of neurons called __________________________), which contains _________ as a

neurotransmitter- most important projections of VTA axons to _________________ (dopamine receptor antagonists in this

region block Medial Forebrain Bundle (MFB) self-stim.)- blockade of dopamine receptors in nucleus accumbenscan also block drug taking behavior in animal models of

addiction.

Mesolimbic systemventral

tegmental area -VTA dopamine

nucleusaccumbens

Treatments of Commonly Abused Substances

General adverse consequences of abused drugs:- ________________________________________- ________________________________________- ________________________________________- ________________________________________- ________________________________________- _________________________________________________________

Expensive habit (associated with crime);IV injections – health risks (HIV, hepatitis);Source can be doubtful and plain dangerous;Crosses placental barrier, making fetus depend;Overdose can produce death;Some drugs can lead to neurological disorders and brain damage.

Neural mechanisms of drug action: act at specific, and often, multiple, synaptic receptors.Common withdrawal symptoms: from 2-3 hours until 6-7 days after last ingestion/dose;

- some withdrawal symptoms: increased fidgeting, sweat, sleep, shiver, nausea, vomiting, diarrhea, cramps, tremors, muscle spasms (legs – going “cold turkey” and “kicking” the habit!)

Specific Treatments:- in some cases, drug specific treatments areavailable (ex. methadone maintenance for opiates)- in general NO GOOD TREATMENTS for anyaddictive drugs!