Psychoactivity and Dependence

Psychoactive Drug

• A chemical substance that alters perceptions, mood, or behavior

Three common psychoactive drugs:– Caffeine– Alcohol– Nicotine

Induce an altered state of consciousness.

Common Properties of Addiction

• Physical dependence

• Tolerance

• Withdrawal symptoms

• Drug rebound effect

Drug Abuse

• Recurrent drug use that results in disruption of academic, social, or occupational functioning or in legal or psychological problems

Dependence

• A state of physiological and/or psychological need to take more of a substance after continued use.

• Withdrawal follows if the drug is discontinued.

Tolerance

• Reduced responsiveness to a drug, prompting the user to increase the dosage to achieve effects previously obtained by lower doses of the drug.

Tolerance

Withdrawal

• The discomfort and distress that follow when a person who is dependent on a drug discontinues the use of the drug

• Withdrawal symptoms are usually the opposite of the drug’s effects – Drug Rebound Effect.

Why do people abuse drugs?Biopsychosocial Theory

Drugs and NeurotransmissionA quick review:• The process whereby neurons

communicate with each other

• Neurotransmission, especially in the brain and spinal cord, helps explain the effects of psychoactive drugs.

• Psychoactive drugs interfere with normal neurotransmission.

Neurotransmitters

• Chemical messengers that cross synaptic gaps between neurons

• When released by the sending neuron, neurotransmitters travel across the synapse and bind to receptor sites on the receiving neuron, setting up the next link in the chain of communication.

Synapse

• The junction between the tip of the sending neuron and the receptor sites on the receiving neuron

• Call the synaptic gap or cleft

Neural Activity

Neurotransmitters and the Synapse

Reuptake

• Process where the unused neurotransmitter chemical is reabsorbed by the sending neuron

Psychoactive Drugs & Synapses• Psychoactive drugs affect synapses

and neurotransmitters in three ways:

–Binding with receptor sites (mimics)*

–Blocking receptor site

–Blocking neurotransmitters’ reuptake*

* Increase the likelihood of the receiving neuron firing

Four Psychoactive Drug Categories• Four different categories we will study:

1. Depressants – depress, inhibit brain activity

2. Opiates – Similar to morphine, produce feelings of euphoria & reduce pain

3. Stimulants – excite brain activity

4. Psychedelic/Hallucinogens/Marijuana – distort sensory perceptions.

– Designer “Club” Drugs – “fifth category” that includes variety of psychoactive drugs.

Depressants

• Drugs that reduce neural activity and slow body functioning

• Includes alcohol and sedatives

• Alcohol—CNS depressant

• Barbiturates—induce sleep

• Tranquilizers—relieve anxiety

Alcohol (ethyl alcohol)

• Found in beer, wine, and liquor

• The second most used psychoactive drug (caffeine first)

• Slows thinking, and impairs physical activity

Blood Alcohol Content (BAC)

• A measure of how much alcohol is in a person’s bloodstream

• BAC of .08 considered legal intoxication in most states

What do we mean by “one drink?”

One 12-ounce can of beer has about the same amount of alcohol as 4 ounces of wine or 1 ounce of whiskey

Euphoric Affects of Alcohol

• Alcohol impairs the parts of the brain responsible for controlling inhibitions and making judgments

• Results in less self-control and sometimes more aggressive behavior.

• Also depends on environment and expectations.

Alcohol, Memory, and Sleep• Studies have shown that alcohol impairs

memory by suppressing the processing of events into long term memory.

• Alcohol impairs REM sleep, further disrupting memory storage.

• Also impairs speech and physical functioning.

• Death can occur if the brain’s respiratory center can no longer function.

Alcohol’s Affect on the Brain

Alcoholism shrinks the brain

Sedatives

• Drugs that reduce anxiety or induce sleep

• Also called tranquilizers

• Include barbiturates and benzodiazepines

Barbiturates

• Drugs that depress the activity of the central nervous system and thereby reduce anxiety

• Can be lethal in overdose and interact with other drugs, especially alcohol

• Impair both memory and judgment• Can create tolerance and physical & mental

dependence• Withdrawal can cause REM rebound

nightmares, hallucinations, disorientation and even life-threatening convulsions.

Benzodiazepines/Tranquilizers

• Drugs that depress that activity of the central nervous system without most of the side effects associated with barbiturates

• Help to reduce anxiety

• Include Valium and Xanax

• Can create dependency

Inhalants

• Chemicals that are inhaled to alter consciousness.

• Paint, glue, gasoline, nitrous oxide & aerosol sprays.

• Low doses may relax and reduce inhibition

• High doses can cause hallucinations and loss of consciousness.

• Toxic to the liver and other organs.

Opiates/Narcotics

• Drugs that depress neural activity, temporarily lessen pain and anxiety and produce feelings of euphoria

• Include: opium, morphine, and heroin

Endorphins

• Natural, opiate-like neurotransmitters linked to pain control and to pleasure

• Body’s natural pain killers

Morphine

• Strong sedative and pain-relieving drug derived from opium

• Works by preventing pain neurons from firing or releasing pain-signaling neurotransmitters (Substance P) into the synapse

Other Opiates

Chemically similar to morphine and have strong pain-relieving properties

• Mimic the brain’s endorphins

• Heroin, methadone

• Percodan, Demerol

Stimulants

• Drugs that excite neural activity and speed up body functions

• Include: caffeine, nicotine, amphetamines, and cocaine

• All are at least mildly addictive.

Caffeine• Stimulant found in coffee, chocolate, tea,

and some soft drinks• Provides user with a sense of increased

energy, mental alertness, and forced wakefulness

• Blocks neurological receptor sites that if activated, sedate the central nervous system

• Withdrawal symptoms are sleepiness, fatigue, anxiety, insomnia, increased heart rate.

Nicotine• Stimulant found in tobacco• Effects similar to those of caffeine –

reduces fatigue & drowsiness and increases mental alertness

• Affects various areas in the brain affecting mood, attention & arousal

• Very addictive and does not stay in the body very long

• See video clip on nicotine addiction.

Cocaine• Stimulant derived from leaves of the coca plant• Crack – cocaine crystals• Blocks the reuptake of certain

neurotransmitters• Dependency is quick and severe; places

extreme strain on cardiovascular system• Can cause cocaine psychosis – schizophrenia-

like symptoms including auditory hallucinations & paranoia, “cocaine bugs” or tactile hallucinations

How Cocaine Works

Amphetamines• Drugs that stimulate neural activity, speeding

up body functions, with associated energy and mood changes

• Includes: speed, uppers, and methamphetamines

• Mimic adrenaline• Can cause irreversible changes in mood &

function by reducing dopamine receptors & transporters.

• Withdrawal causes fatigue, deep sleep, intense depression, increase in appetite.

Hallucinogens/Psychedelic Drugs

• Drugs that distort perceptions and evoke sensory images in the absence of sensory input

• Include: LSD, Mescaline and Marijuana

Lysergic Acid Diethylamide (LSD)

• Powerful hallucinogenic drug

• Also known as “acid”

• The effects vary from person to person

• Users can be dangerous to themselves and others.

• Similar to neurotransmitter, serotonin.

• Flashbacks, psychotic reactions can occur.

Marijuana• Leaves, stems, resin, and flowers form the

hemp plant • When smoked, lower inhibitions and produce

feelings of relaxation and mild euphoria• THC (delta-9-tetrahydrocannabinol) is the

active ingredient. Receptors in the brain for anandamide also accept THC

• Disrupts memory; lung damage from smoke• Withdrawal may cause insomnia, tremors and

decreased appetite.• Is helpful in decreasing nausea and reducing

effects of glaucoma.

“Club” Drugs

• Ecstasy (MDMA)—feelings of euphoria, increased well-being.

• Side effects—dehydration, hyperthermia, tremor, rapid heartbeat

Ecstasy• Hallucinogenic drug that produces lower

inhibitions, pleasant feelings, and greater acceptance of others

• Also called MDMA• Blocks serotonin reuptake prolonging its “good”

feeling• Even moderate users may experience permanent

brain damage to serotonin nerve endings & even memory and verbal reasoning problems up to a year later.

• Dehydration, rapid heartbeat, tremors, muscle tension, teeth clenching & high body temp can result.

Other “Club” Drugs:Dissociative Anesthetics

• Dissociative anesthetics—include PCP and Ketamine. • Deaden pain, produce stupor or coma, may induce

hallucinations• Create feelings of dissociation & depersonalization• PCP or angel dust, ketamine• Effects of “trips” differ for each person• Can result in hyperthermia (high body temp), convulsions &

death.• Affects neurotransmitter glutamate causing a release of more

dopamine in the brain.• Highly addictive.• Long term effects can be memory loss and depression.