Consciousness, Sleep, and Altered States



A person's subjective awareness of their internal mental states and environment can be influenced by consciousness, sleep, and altered mental states. Most cognitive, emotional, and perceptual processing takes place outside of conscious awareness. People become aware of their internal states when they either deliberately focus their attention on them (such as when recalling a memory) or when something in the environment captures their attention (such as when they overhear someone mention their name at a party). Dreaming, hypnosis, and psychoactive drugs involve altered states of consciousness.

At A Glance

  • Consciousness is an individual's subjective awareness of their internal mental states and environment. Most cognitive, emotional, and perceptual processing takes place outside of conscious awareness.
  • Attention involves focusing on specific stimuli to the exclusion of other stimuli.
  • People are both unaware of many aspects of their environment and blind to that lack of awareness. This failure to notice stimuli and environmental changes can cause accidents.
  • Living things go through physical states linked to the 24-hour cycle of light and darkness. In humans, these changes influence strength, alertness, temperature, and hormone levels.
  • Sleep consists of multiple stages that repeat in 60- to 90-minute cycles. Dreams occur mostly during rapid eye movement (REM) sleep, which is characterized by rapid eye movements and heightened brain activity.
  • Sleep deprivation has many negative impacts, including reduced immune function, impaired cognition, memory disruption, hormonal disruption, and weight gain.
  • Insomnia, sleep apnea, and narcolepsy are common causes of sleep deprivation. Sleepwalking, night terrors, and sleep paralysis are caused by transitional glitches between sleep states or between sleep and waking states.
  • Psychoanalytic therapists use dream interpretation in therapy. Modern scientific exploration of dreams suggests they play a role in storing memories and developing neural pathways.
  • The main categories of psychoactive drugs are depressants, opiates, stimulants, and hallucinogens.
  • Genetic factors, disruptions in the brain's reward pathways, and prenatal drug exposure increase risk for substance abuse.
  • Environmental cues trigger the bodies of long-time drug users to counteract drug effects. This increases drug tolerance, makes relapse more likely, and increases overdose risk in unfamiliar environments.
  • Stress, distress, risk-taking, impulsivity, negative peer influences, and cultural acceptance of substance use increase risk for substance abuse.
  • Hypnosis is an altered state of consciousness in which a person becomes highly suggestible, although people vary in their degree of hypnotizability.