PSY 340 Brain and Behavior
Class 09: Substance Abuse and Addiction (Outline)
- Jimi Hendrix (1942-1970). Musician. Alcohol & barbiturate overdose. Inhalation of vomit.
- Philip Seymour Hoffman (1967-2014). Actor. Heroin overdose.
- Whitney Houston (1963-2012). Singer, actress. Accidental drowning. Cocaine + Benadryl, Flexeril, Xanax.
- Michael Jackson (1958-2009). Singer. Homicide. MD administration of propofol, lorazepam, diazepam, & midazolam.
- Heath Ledger (1979-2008). Actor. Accidental. "died of the combined effects of five (5) prescription & one (1) over-the-counter medications: oxycodone, hydrocodone, diazepam, temazepam, alprazolam, and doxylamine (Unisom®)
- Mac Miller (1992-2018). Rapper, songwriter. Accidental overdose of fentanyl, cocaine & alcohol
- Prince Rogers Nelson (1958-2016) Accidental overdose of fentanyl
- Lil Peep (Gustav Ahr; 1996-2017). Rapper and singer. Multiple Xanax (alprozalam) pills. Blood showed traces of cannabis, cocaine, tramadol, hydrocodone, hydromorphone, oxycodone, & oxymorphon.
I. Drug Mechanisms
Types of Drug Effects
- Antagonist: blocks
- Agonist: increases or mimics
- Mixed agonist-antagonists
Other Qualities of Drugs
- Affinity: tendency of a drug to bind to a receptor (strong to weak)
- Efficacy: tendency of a drug to activate a receptor (high to low)
Some Drugs of Abuse (not in
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")
Common opiates include
4. MarijuanaThey 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.
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.
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
- "long form" dopamine type 4 receptors: these receptors tend to be less sensitive to ETOH and, thus, people tend to consume more, and
- more active form of COMT (enzyme breading down DA) leading to lower levels of reinforcement & higher levels of impulsiveness.
ii. Among sons of alcoholics, alcoholism is associated with
- less than average intoxication after drinking a moderate amount of alcohol.
- experiencing more than average relief from tension after drinking alcohol.
- having a smaller than normal amygdala in the right hemisphere
iii. Genetic influences on drug abuse
- Strong evidence for polygenetic influences on alcoholism, cocaine use, and some other drugs.
iv. Environmental Influences
- Mothers who drink alcohol during pregnancy have children with a greater risk of alcoholism in later life
- Children with a variant gene for a less sensitive GABA receptor tend to have impulse control problems (including drug use) unless they grow up in families which clear parental supervision.
- Medications to Combat Opioid Abuse
- The most effective medical treatment for opioid (heroin, etc.) abuse in patients who have failed to "kick their habit" by more traditional treatment methods is the use of suboxone or methadone.
- Note that our textbook says, "these drugs do not end the addiction. They merely satisfy the craving in a less dangerous way" (p. 472). When the alternative to suboxone and methadone is so frequently death, it would seem that keeping people alive ought to be the principal goal of health care providers.