Biological Bases of Behavior - States of Consciousness: Psychoactive Drugs

UNIT 2: Biological Bases of Behavior

PART II: States of Consciousness

Module 18: Psychoactive Drugs

Psychoactive Drugs and Substance Abuse Disorders

• Psychoactive drugs:

  • Definition: Chemical substances that alter perceptions and moods.

• Substance abuse disorder:

  • Definition: A disorder characterized by continued substance craving and use despite significant life disruption and/or physical risk.

Diagnosis of Substance Use Disorders

• When is drug use considered a disorder?

  • Diagnostic consideration based on 11 statements (further details on thresholds for diagnosis are implied).

• Severity of Substance Use Disorder:

  • Mild: 2-3 indicators.

  • Moderate: 4-5 indicators.

  • Severe: 6 or more indicators.

  • Reference: American Psychiatric Association, 2013.

Tolerance and Addiction

• Tolerance:

  • Definition: The diminishing effect with regular use of the same dose of a drug, requiring larger dosages for effect.

• Addiction:

  • Definition: A primary, chronic disease of brain reward, motivation, memory, and related circuitry.

• Characterization of Addiction:

  • Inability to consistently abstain.

  • Impairment in behavioral control.

  • Craving.

  • Diminished recognition of significant problems in behaviors and relationships.

  • Dysfunctional emotional response.

  • Despite adverse consequences, addiction leads individuals to desire the drug more than the enjoyment derived from it.

Neuroadaptation and Substance Use Disorder

• How tolerance leads to substance abuse disorder:

  • Neuroadaptation occurs when brain chemistry changes to offset drug effects, leading to increased dosage requirements, which heightens the risk of addiction.

Withdrawal Effects

• Withdrawal:

  • Definition: The discomfort and distress that follow discontinuation of an addictive drug or behavior.

  • Note: Most ex-smokers succeed in quitting without assistance (Newport, 2013).

Evolution of Addiction Concept

• Change in concept of addiction:

  • Certain behaviors can become compulsive and dysfunctional, similar to problematic use of alcohol and drugs.

  • The DSM5 includes classifications like gambling disorder while other behavior addictions (e.g., internet gaming disorder) are still under study.

Categories of Psychoactive Drugs

• Three major categories:

  1. Depressants

  2. Stimulants

  3. Hallucinogens

• Importance for AP Exam:

  • Understanding classification and effects of psychoactive drugs is crucial for exam questions.

Depressants and Their Effects

• Definition of depressants:

  • Drugs such as alcohol, barbiturates, and opiates that reduce neural activity and slow body functions.

Alcohol

• CNS Depressant:

  • Alcohol is classified as a central nervous system depressant that slows brain and spinal cord activity.

Interaction with Neurotransmitters

• GABA:

  • Alcohol acts as an agonist on GABA receptors, enhancing inhibitory effects.

• Glutamate:

  • Alcohol serves as an antagonist to glutamate receptors, preventing excitatory neural activity.

Impact on Brain Structure

• MRI Findings:

  • Brain shrinkage evidenced in those with alcohol use disorder, visible through larger ventricles compared to control groups.

Impairment of Reaction Time

• Effects on reaction time and cognitive functions:

  • Slowed neural processing leads to impaired reactions, slurred speech, and diminished skill performance.

Awareness of Intoxication

• Drunken state awareness:

  • Research shows intoxicated individuals are often unaware of their level of intoxication (Moore et al., 2016).

Memory and Self-Awareness Disruption

• Memory formation:

  • Alcohol disrupts memory consolidation by inhibiting REM sleep.

• Self-awareness:

  • Alcohol consumption may cloud awareness, particularly regarding failures or shortcomings.

Expectancy Effects

• Definition:

  • Behavioral influence based on expectations surrounding alcohol consumption (Christiansen et al., 2016).

Barbiturates

• Definition:

  • Drugs that depress CNS activity; used for sleep induction and anxiety reduction but impair memory and judgment.

• Examples:

  • Nembutal, Seconal, Amytal.

Opiates

• Definition:

  • Drugs like opium, morphine, and heroin that depress neural activity and alleviate pain and anxiety.

• Consequences of addiction:

  • Users experience cravings, tolerance, and withdrawal discomfort, potentially leading to overdose deaths due to withdrawal from artificial opiates.

Stimulants and Their Effects

• Definition of stimulants:

  • Drugs (e.g., caffeine, nicotine, cocaine, amphetamines, methamphetamine, Ecstasy) that excite neural activity and accelerate body functions.

Nicotine

• Definition:

  • A highly addictive psychoactive drug found in tobacco products.

Tobacco Use Statistics

• Life Expectancy:

  • Smokers have a life expectancy at least 10 years shorter than nonsmokers. Annual tobacco deaths projected to reach 8 million by 2030 (WHO, 2012).

Physiological Effects of Nicotine

• Speed of Reaction:

  • Nicotine reaches the brain in 7 seconds, impacting rapid physiological responses.

Cocaine

• Definition:

  • A potent stimulant derived from coca, inducing heightened alertness and euphoria.

• Mechanism of Action:

  • Blocks reuptake of neurotransmitters, leading to increased presence in the synapse, enhancing mood effects followed by a crash.

Methamphetamine

• Definition:

  • A potent stimulant causing accelerated body functions with serious long-term effects, including decreased baseline dopamine levels.

Ecstasy (MDMA)

• Definition:

  • A synthetic drug with stimulant and mild hallucinogenic effects.

• Mechanism:

  • Triggers both dopamine release and serotonin release while blocking serotonin reuptake.

• Research Findings:

  • Can lead to dehydration, increased blood pressure, serious health risks, and long-term cognitive effects.

Hallucinogens and Their Effects

• Definition of hallucinogens:

  • Psychedelic drugs like LSD that distort perceptions and elicit sensory images in absence of external stimuli.

LSD

• Definition:

  • A powerful hallucinogen with unpredictable emotional experiences from euphoria to panic.

Marijuana (Cannabis)

• Classification:

  • Typically categorized as a milder hallucinogen with various sensory enhancements.

• Main Ingredient:

  • THC (delta-9-tetrahydrocannabinol) responsible for psychoactive effects.

Comparison of Psychoactive Drugs

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