[Last updated:]

Feb 25, 2021



 PSY 340 Brain and Behavior

 Class 09: Substance Abuse and Addiction (Outline)



Celebrity Overdose Deaths
Deaths in the US due to selected causes 1958-2018

Surging Rates of Heroin & Prescribed Opioid Deaths in the US

Opiod deaths by sex
            Deaths by Age

            Deaths by type

Drug Deaths in US 2003 vs. 2017

   Who is dying? "Deaths of Despair" (overdose, suicide & alcohol-related deaths)
   among White non-Hispanic non-college graduates

  Changes in Mortality 1999-2015
Deaths of Despair

I. Drug Mechanisms

Drug Effects on Dopamine SynapsesTypes of Drug Effects

Other Qualities of Drugs

II. Similarities and Differences among Addictive Substances

Self-stimulation in ratnucleus accumbensJames Olds & Peter Milner (1954) found areas in rat's brain which leads to continual self-stimulation: reinforcement via the nucleus accumbens.

Dopamine carries more information than simple reinforcement, e.g., helping remember pleasure and signaling that a reward is either greater or smaller than predicted.

Most drugs of abuse are likely to increase the release of dopamine and norepinephrine with effects on the n. accumbens.
Cravings. Attention-getting or arousal = salience.

Reinforcement (= reward) involves both
Tolerance and Withdrawal.

Some Drugs of Abuse (not in book) 

   1. Stimulant drugs (e.g., amphetamines, cocaine, etc.)

a. Amphetamine increases dopamine (DA) release from presynaptic terminals and also reverses the direction of the dopamine transporter (reuptake gate) which makes more DA available.

b. Cocaine ("coke") blocks the reuptake of DA, NE, and serotonin at the synapse.

c. Methylphenidate (Ritalin®): Stimulant currently prescribed for Attention Deficit Disorder (ADD)

--> the use of Ritalin® when used as prescribed does not lead to the use of other drugs in later life.

e. MDMA (methylenedioxymethamphetamine or "Ecstasy")

        Smoke]   2. Nicotine

Stimulates the nicotinic receptor (a type of acetylcholine [ACh] receptor) both in the central nervous system and neuromuscular junction of skeletal muscles. CNS nicotinic receptors tend to lie on neurons which release DA in the nucleus accumbens.

    3. Opiates [or opioids] (Narcotic: Derived from (or similar to those derived from) the opium poppy)

[Poppy Cultivation & Heroin]
Common opiates include

Mrs. Winslow's Soothing
Opiates affect different receptor types in the brain.
They will also decrease (inhibit) other opiate receptors & cause a range of effects such as analgesia (pain relief), decreased respiration, lowered motility of the GI system (anti-diarrhea), and physical dependence.
   4. Marijuana
5. Alcohol and Alcoholism

A. Alcoholism or alcohol dependence

B. Alcohol (ethanol, ETOH): Inhibits Na+ ion flow across the neuron membrane; decreases serotonin activity, facilitates transmission at the GABAA receptor, blocks glutamate receptors, and increases dopamine activity. Thus, alcohol is mostly an INHIBITORY substance.

C. Types

a. Type I Alcoholism

b. Type II Alcoholism

D. Predispositions for Alcoholism & Substance Abuse

i. Alcoholism: Tends to be more likely among those who, as children, were described as impulsive, risk-taking, easily bored, sensation-seeking, & outgoing.

Associated with genes causing

ii. Among sons of alcoholics, alcoholism is associated with

iii. Genetic influences on drug abuse

iv. Environmental Influences