Lec 24

Introduction to Psychopharmacology and Recreational Drugs

• Focus on synaptic transmission and psychopharmacology in PSYCH 205, Lecture 24.

• Transitioning from therapeutic drug examples to recreational drug use.

• Upcoming focus: nicotine, alcohol, and marijuana.

Key Questions in Psychopharmacology

• Major questions guiding the field:

  • Effects of Drugs: What psychological and physiological effects do drugs produce?

  • Mechanisms of Action: How do drugs impact the brain? What changes occur?

  • Modulating Factors: What external factors influence drug responses?

  • Reasons for Drug Use: Why do individuals take drugs, especially despite negative consequences?

  • Treatment Approaches: Strategies for helping individuals reduce or cease drug use.

• Details on addiction studies available at VIU.

Effects of Drugs: Psychological vs Physiological

• Distinction between psychological and physiological effects:

  • Psychological Effects: Changes in behavior and mental processes.

  • Physiological Effects: Biological changes in bodily processes.

• Importance of understanding dosage:

  • Dosage Definition: Not just the amount taken, but the quantity that reaches effective sites in the brain (functional dosage).

  • Influence of Route of Administration: Method of taking the drug impacts absorption and effects.

Routes of Drug Administration

• Oral: Slow absorption via the gastrointestinal system; variable depending on food intake.

• Inhalation: Rapid absorption through lungs, ideal for quick onset effects.

• Injection: Fastest method, varying speeds based on injection site (intravenous, intramuscular, subcutaneous).

• Transnasal/Transdermal: Absorption through nasal passages or skin; slower but effective for certain substances.

Widespread Nature of Recreational Drugs

• Recreational drug use is common in society, with various public health issues associated.

• Challenges in accurately measuring drug prevalence due to reliance on self-reported data.

• Estimations indicate:

  • Illegal Drug Use: Approx. 1 in 15 adults used illegal drugs in the past month.

  • Therapeutic Drug Misuse: Regular recreational use in about 1 in 50 adults.

  • Legal Drugs: 25% of adults smoke tobacco; ~50% consume alcohol; ~80% regularly use caffeine.

Focus on Nicotine

• Source: Active ingredient from tobacco; indigenous to South America.

• Historical context of its global spread; strong social and health controversies.

• Nicotine is highly addictive and has multiple routes for administration, primarily through inhalation.

Biological Effects of Nicotine

• Classed as a stimulant; enhances brain activity and cognitive functions.

• Effects on behavior:

  • Increased arousal and alertness.

  • Improved attention, memory, and suppresses appetite.

  • Potential for nausea/vomiting at higher doses; tolerance develops quickly.

  • Changes in cognition post-cessation; temporary decrease in effectiveness when quitting.

• Physiological effects:

  • Cardiovascular Impact: Increases heart rate and blood pressure, contributing to cardiovascular problems.

  • Muscle Effects: Reduced muscle tone, leading to feelings of relaxation.

Mechanism of Action of Nicotine

• Agonist for Acetylcholine: Binds to nicotinic receptors, activating sodium channels.

• Results in neuronal excitation and increased activity in brain circuits related to cognition and muscle action.

• Chronic nicotine exposure reduces receptor availability, impacting muscle tone.

Health Risks Associated with Nicotine Use

• Chronic nicotine use poses significant health risks regardless of administration route:

  • Increased risk of lung disease, cardiovascular issues, heart attacks, and strokes.

• Notable studies highlight the extreme nature of nicotine addiction, such as preference over basic needs.

Conclusion

• Recap of nicotine’s significance in recreational drug use, effects, and health implications.

• Importance of awareness concerning the addictive nature of nicotine and its societal prevalence.