Stages of sleep and REM Psychoactive drugs Stimulants Depressants Alcohol Hallucinogens

Stages of Sleep and REM

1. Stages of Sleep

   • Stage 1 (Non-REM)
     • Light sleep; easily awakened.
     • Theta waves begin to emerge on EEG.
     • Hypnic jerks (sudden muscle contractions) may occur.
   • Stage 2 (Non-REM)
     • Deeper sleep; harder to awaken.
     • Sleep spindles (bursts of rapid brain activity) and K-complexes appear on EEG.
     • Body temperature drops and heart rate slows.
   • Stages 3 & 4 (Non-REM)
     • Deepest sleep stages, also known as slow-wave sleep (SWS).
     • Delta waves dominate EEG readings.
     • Very difficult to awaken; sleepwalking and night terrors are most likely to occur.
     • Essential for physical restoration.

2. REM (Rapid Eye Movement) Sleep

   • Brain activity resembles wakefulness; EEG shows fast, desynchronized waves.
   • Vivid dreaming occurs.
   • Muscle atonia (temporary paralysis) prevents acting out dreams.
   • Heart rate and breathing become irregular.
   • REM periods become longer and more frequent toward morning.
   • Important for cognitive functions such as memory consolidation and learning.

Psychoactive Drugs

1. Stimulants

   • Drugs that increase central nervous system activity.
   • Examples: caffeine, nicotine, amphetamines, cocaine.
   • Physiological Effects: Increased heart rate, blood pressure, alertness, and energy.
   • Psychological Effects: Euphoria, increased confidence, reduced fatigue.
   • Risks: Addiction, anxiety, insomnia, cardiovascular problems.

2. Depressants

   • Drugs that decrease central nervous system activity.
   • Examples: alcohol, barbiturates, benzodiazepines.
   • Physiological Effects: Slowed heart rate and breathing, muscle relaxation, reduced coordination.
   • Psychological Effects: Relaxation, reduced anxiety, sedation.
   • Risks: Addiction, respiratory depression, impaired judgment, overdose.

3. Alcohol

   • A widely used depressant.
   • Physiological Effects: Impairs motor skills, reduces inhibitions, affects judgment.
   • Psychological Effects: Relaxation, euphoria, altered mood.
   • Long