Consciousness: Sleep, Dreams, and Psychoactive Drugs

Consciousness

Definition and States

Consciousness refers to our subjective experience of the world, our bodies, and our mental perspectives. It encompasses both waking consciousness and altered states of consciousness.

• Waking consciousness: Awareness of thoughts, feelings, and environment.

• Altered states of consciousness: Includes sleep paralysis, locked-in syndrome, out-of-body experiences, near-death experiences, mystical experiences, hypnosis, meditation, and effects of psychoactive drugs.

Sleep and Circadian Rhythms

Circadian Rhythm

Circadian rhythms are biological cycles that occur roughly every 24 hours, regulating sleep, hunger, hormone secretion, and other bodily functions.

• Regulation: Controlled by the suprachiasmatic nucleus (SCN) in the hypothalamus, which acts as the brain's clock mechanism.

• Synchronization: The SCN receives light information from the retina, allowing it to synchronize with the external environment's light-dark cycle.

• Physiological effects: Body temperature, hormone production, and blood pressure follow circadian rhythms.

What is Sleep?

Sleep is a state of low physical activity and reduced awareness, associated with the secretion of several hormones:

• Melatonin

• Follicle stimulating hormone

• Luteinizing hormone

• Growth hormone

Stages of Sleep

Sleep occurs in 5 stages, cycling every 90 minutes:

• Stages 1-4: NREM (Non-Rapid Eye Movement) Sleep

  • No eye movements, fewer dreams.

  • Stage 1: Transition from wakefulness to sleep (10-15 min), brain waves slow, brief dream-like images.

  • Stage 2: Further slowing of brain waves, presence of sleep spindles and K-complexes (may help maintain sleep and memory storage), about 65% of total sleep, lasts ~20 min.

  • Stages 3 & 4: Deep sleep, delta waves, crucial for feeling rested, growth hormone production, more time spent in these stages by children, suppressed by alcohol, hardest to awaken from stage 4.

• Stage 5: REM (Rapid Eye Movement) Sleep

  • Vivid dreams, rapid eye movements, brain waves similar to wakefulness.

  • Antonia (muscle paralysis), active brain but inactive body.

  • REM rebound: increased REM after deprivation.

Hypnagogic State

The hypnagogic state is the transitional phase between wakefulness and sleep, characterized by:

• Hypnagogic imagery: visual, somatic, and auditory sensations.

• Myoclonic/hypnic jerk: sudden muscle contractions.

Functions and Theories of Sleep

Why Do We Sleep?

• Adaptive (Preserve & Protect Hypothesis): Sleep helps restore resources and protect from predatory risks, but increases vulnerability.

• Restorative (Restore & Repair Hypothesis): Sleep restores and replenishes the body, supports memory consolidation, learning, and cognitive function, especially during slow-wave sleep.

• Essential for Growth: Necessary for brain development, though the full reasons for sleep are not completely understood.

Sleep Deprivation and Displacement

Sleep Deprivation

• Degeneration of neurons in the brainstem.

• ADHD-like symptoms, increased risk of physical illness, family problems, and substance abuse.

• Effects comparable to a blood alcohol concentration (BAC) of 0.07.

Sleep Displacement

• Occurs when sleep is prevented at the normal time (e.g., jet lag, caffeine before bed).

• Can delay the internal clock and disrupt sleep quality.

Disruptions of Normal Sleep

• Jet lag: Mismatch between internal circadian cycles and environment, causing fatigue and irritability.

• Rotating shift work: Alters circadian rhythm, leading to exhaustion, agitation, depression, and anxiety. Bright light therapy can help realign the biological clock.

• Shift work effects: Can age the brain by over 6 years, reduce memory and processing speed, but effects are reversible (~5 years to recover).

• Daylight savings time: Associated with increased car accidents due to sleep disruption.

Sleep Deprivation & Mental Health

• Increased stress, emotional overreaction, and impaired emotional regulation (amygdala activation without frontal cortex regulation).

• Example: Peter Tripp's 200-hour wakeathon led to hallucinations, paranoia, and personality changes.

Sleep Hygiene (for Students)

• Maintain a regular sleep-wake schedule.

• Ensure a quiet sleep environment.

• Avoid caffeine after lunch and stimulating activities before bed.

• Use the bed only for sleep, not as an all-purpose area.

Sleep Disorders

Insomnia

• Difficulty falling or staying asleep for at least 3 nights a week, for at least 1 month.

• Affects 9-20% of people; higher among students (~25%), especially with ADHD or depression.

• Treatment: Psychotherapy and/or hypnotic medications (e.g., Lunesta, Ambien), but concerns about tolerance and side effects.

Paradoxical Insomnia

• Sleep-state misperception: Belief of being sleep deprived despite normal sleep cycles.

• Associated with distress, anxiety, and fatigue; cause is unclear but may involve brain arousal during sleep.

Night Terrors & Sleep Apnea

• Night terrors: Sudden waking with screaming and confusion, most common in children (ages 3-8), generally harmless.

• Sleep apnea: Blockage of the airway during sleep, can lead to serious health risks (e.g., SIDS).

Narcolepsy

• Rapid and unexpected onset of sleep, directly into REM sleep.

• Includes cataplexy (sudden loss of muscle tone), affects humans and animals, associated with lack of orexin.

Other Sleep Disorders

• REM behaviour disorder: Lack of paralysis during REM, allowing individuals to act out dreams.

• Somnambulism (sleepwalking): Occurs during stage 3 sleep, individuals walk while fully asleep, safe to wake.

Dreams: Function and Meaning

Freud's Theory

• Dreams as unconscious wish fulfillment.

• Distinction between latent content (hidden meaning) and manifest content (actual storyline).

• Symbolic interpretation of dream elements.

Evolutionary Theory

• Problem-solving theory: Dreams help process stressful or threatening information, allowing for 24/7 information processing.

• Example: Kurdish children had more intense, threatening dreams than Finnish children, reflecting daily life stressors.

Neuroscience Theory

• Activation-synthesis theory: Dreams are the brain's attempt to make sense of random neural activity during sleep.

• Dream content reflects the dreamer's fears, emotions, and concerns; motivational and emotional centers are active during REM, with less prefrontal cortex involvement.

Psychoactive Drugs

Definition and Effects

Psychoactive drugs are substances that contain chemicals similar to those found naturally in the brain, altering neurotransmission and influencing emotions, perceptions, and behaviors. They can create physiological or psychological dependence.

Stimulants

• Speed up nervous system activity, enhancing wakefulness and alertness.

• Caffeine: Most commonly used, blocks adenosine (which normally slows brain activity).

• Cocaine: Small doses increase well-being and energy; large doses can cause anger and paranoia. Blocks dopamine reuptake, flooding the brain with dopamine.

• Amphetamines: Strong stimulants (e.g., Dexedrine, Benzedrine, methamphetamine) stimulate dopamine release, can cause neurological and physical problems, and alter brain structure.

• Amphetamines & ADHD: Drugs like Adderall and Vyvanse increase dopamine, serotonin, and norepinephrine; help ADHD patients focus, but can cause euphoria in non-ADHD users.

• MDMA (also a hallucinogen): Increases serotonin, heightens sensations, increases social bonding, but can lower mood post-use and alter brain structure with chronic use.

Hallucinogens (Psychedelics)

• Produce hallucinations or changes in perception (e.g., LSD, psilocybin, ayahuasca, marijuana, ecstasy, salvia).

• Interest in therapeutic value for mystical experiences and treatment-resistant conditions.

• MDMA & LSD: MDMA increases empathy and connection; LSD produces vivid hallucinations, alters sensory perception, and increases neural communication.

Marijuana (THC: Tetrahydrocannabinol)

• Effects are a mix of excitatory, depressive, and mild hallucinatory.

• Triggers spontaneous ideas, distorts perceptions, increases sensitivity to stimuli, impairs memory (due to cannabinoid receptors in the hippocampus).

• Prolonged use can impair cognitive function (reversible) and reduce dopaminergic function.

• High THC content, frequent use, and early onset increase risk of cannabis-induced psychosis (hallucinations, delusions, disorganized thinking).

• Today's cannabis is much stronger than in the 1970s (over 10 times more THC).

Depressants

• Reduce arousal and stimulation by decreasing neurotransmission and electrical activity.

• Includes alcohol, opioids, benzodiazepines; used to treat anxiety, panic, and sleep disorders.

Alcohol

• Most commonly used depressant; stimulating at low doses (via dopamine), depressant effects at higher doses.

• Lowers inhibition, impairs judgment, magnifies emotions; females experience stronger effects at the same dose.

• Balanced-placebo design shows expectations influence social behavior more than physiological effects.

BAC	Effects
0.01-0.05	Behavior and judgment slightly affected, not intoxicated
0.03-0.12	Blurred vision, slurred speech, impaired coordination
0.09-0.25	Alcohol poisoning, senses severely impaired
0.25-0.35	Coma risk, compromised respiration and circulation
0.45	Alcohol poisoning may cause death

Sedatives

• Barbiturates: Induce sleep or relaxation, psychologically and physically addictive, deadly with alcohol.

• Benzodiazepines: Treat anxiety and panic, highly addictive, excessive use leads to tolerance and memory impairment, deadly with alcohol.

• Quaaludes (Methaqualone): CNS depressant, sedative and hypnotic (increases GABA), banned due to high abuse potential.

Opioids

• Derived from poppy seeds, bind to opioid receptors, produce euphoria and pain relief.

• Includes prescription drugs (oxycodone, morphine, fentanyl) and illegal drugs (heroin).

• Highly addictive, can cause respiratory depression and overdose.

• Cycle of addiction: drug is used to avoid withdrawal rather than to feel good.

• Opioid overdose deaths have increased in waves, surpassing other causes of death in some years.