Nightmares are unpredictable, but are linked to stress, anxiety, trauma, and more.

What do your dreams mean, according to science

Humans have been interpreting dreams as signs from deities, spirits, or the psyche for ages, and research shows that reflecting on and analyzing one's dreams can be beneficial. In alignment with dreams' elusive nature, they have no objective or clearly assigned meaning. However, variations of common dreams, such as a surprise exam in a forgotten class, are rife with shared primal fears.

Dream interpretation has evolved from ancient mystical explanations, to dream reports, to tracking electrical activity in the brain and more.

How do anxiety and stress differ?

This article explains that though “stress” and “anxiety” are often used interchangeably, there are distinct differences between the two. Stress is defined as the body's response to an external trigger and can be classified as acute or chronic. Anxiety, however, tends to be triggered internally by excessive thoughts and judgement. Whereas stress disappears when the trigger is gone, anxiety tends to stick around. If left unchecked, both can escalate into more severe mental health conditions.

Ghost stories across cultures often trace back to traumatic events

From a bat-like demon in Tanzania to a malevolent woman figure hovering above your sleeping body, the four disturbing tales outlined in this NPR article offer a glimpse into how happenings from WWII or the Aztec Empire haunt people’s memories.

Stress is a response to external triggers, while anxiety is persistent and internal

When distinguishing the two, stress is a reaction to identifiable situations like deadlines or conflicts, and its symptoms fade when the stressor is gone. However, anxiety may jump from one worry to another over time without any apparent cause.

Sleep paralysis occurs when the body fails to 'unfreeze' in sync with waking.

Narcolepsy occurs when the brain loses its ability to control its sleep-wake cycle

Narcolepsy not only makes people fall asleep at random moments, but it can also cause hallucinations, insomnia, and sleep paralysis. The disorder is tied to cells in the brain’s hypothalamus called hypocretin, which are neuropeptides responsible for keeping you awake and controlling your dreaming from coming on too quickly.

Why don’t you remember all your dreams?

Despite being a near-nightly occurrence, we remember very few of our dreams. Researchers believe reduced activity in regions where memories are stored, a different neurochemical environment during sleep, and rapid transition during waking contribute to this phenomenon.

Fearology, or the study of fear, explores the difference between stress and fear

Our brains involuntarily respond to our environment and signal alarm when that isn't always needed, triggering responses that include goose bumps. But understanding fear and how to talk our brains into calming down can improve daily life.

We dream for around two hours each night, on average, but the exact purposes of dreams remains under investigation.

An estimated 1 in 250 people—a small subset of the population—reports they've never remembered a single dream.

Dreams largely occur during REM sleep (but not entirely).

The study of dreams, formally called oneirology, has evolved over the centuries, from anecdotal interpretations to advanced brain imaging.

The dreaming brain, as understood by scientists

Technology has advanced to where the seemingly separate fields of psychology and neuroscience are asking the same questions about dreams, such as whether they're more closely related to perception or visualization. Some field-intersecting findings include research that shows people with impaired face perception don't dream of faces, those with brain legion-related cognition difficulties deal with similar issues in dreams, and children's dreams change in parallel to their cognitive development.

A framework for the various potential causes of insomnia

Insomnia typically occurs in people dealing with life stressors and physical or mental health conditions, though the exact cause continues to elude researchers. Generally, the factors can be broken down into external (such as stress, medication, etc.) or internal (neurological) factors.

Why do dreamers twitch?

This thought-provoking piece highlights newer research suggesting sleep twitches may not be random dream leftovers, but instead a crucial way our brains map and understand our bodies. From sleeping rat pups to dreaming octopi, this biological mapping system appears universal across animal species.

Dreams have long been used for religious and political power.

NDEs typically change people's outlooks drastically and can prompt depression

The phenomena are regularly categorized as hallucinations, but some specialists are interested in their psychological nuances. Many survivors report feeling less anxiety about death, though some surveys show the experiences can increase physiological sensitivities.

The REM cycle—named for the 'Rapid Eye Movement' that occurs during this stage of intense dreaming—happens around four to six times per night.

For most of recorded history dreams were considered divine in origin.

Apophenia, the cognitive bias that leads people to find meaning in randomness, helps explain why humans look for meaning in their dreams and even in their tea leaves.

Sleep disorders can exacerbate neurological and other health conditions

Brain regions that control sleep sit adjacent to those that regulate the autonomic nervous system, which controls involuntary bodily functions like heart and breathing rates. These neighbors influence each other, meaning poor sleep can impair or negatively impact the ANS, further disturbing sleep.

During dream sleep, the brain connects new information learned during the day with information already stored in the mind, creating a revised mind-wide web of associations.

The benefits of lucid dreaming

Lucid dreams happen when the dreamer knows they've stepped out of the bounds of waking life. Studies show it can help dreamers cultivate creativity, process grief, and work through trauma. A 2021 study found that 85% of participants with PTSD no longer qualified for the diagnosis after a week of trauma-informed lucid dreaming in which they intentionally witnessed (and therefore integrated) recurring nightmares or changed the outcome completely.

'Those who dream by day are cognizant of many things which escape those who dream only by night.'

- Edgar Allan Poe (1809-1849) in "Elenora"

Sleepwalking, or somnambulism, is a bit of a misnomer since many things can occur during this state, including speaking, using the bathroom, and more.

Why are humans hooked on horror?

A haunted horror attraction in Denmark is regularly stalked by researchers of the world's only laboratory dedicated to understanding fear's good side. Fear is one of many human emotions that correspond to a physiological response. As fear rises, so do adrenaline, cortisol, and heart and breath rates. As it ebbs, the body is flooded with dopamine, a hormone and neurotransmitter associated with desire, learning, and motivation.

Scientists are learning to guide your dreams using sound and touch.

Visualizing how we dream via Google search trends

When dreams perplex us, we often want to understand them—and in the age of Google, millions go to its search engine to find answers. Now, researchers have compiled a decade's worth of dream-related queries to glean dream trends across seven languages. See what dream was most commonly searched in Arabic in 2015, or what fears and hopes are specific to one culture and time alone with this unique visual essay.

Dreaming under the Nazi Regime

Days after Hitler seized power, a man told psychoanalyst Charlotte Beradt that he had dreamed of being forced to raise his arm in a Nazi salute ("It took me half an hour to get my arm up, inch by inch"). Beradt recorded this dream and many others so they "might one day serve as evidence." This is an English translation of her work, "The Third Reich of Dreams."

The overlooked physical causes of insomnia

Persistent lack of sleep is dangerous for anyone, but women are especially unlikely to have their symptoms taken seriously. This article highlights the physical causes of insomnia—a condition often written off as solely psychological—and the importance of early diagnosis. The writer, Courtney Maum, was diagnosed with an anterior nasal valve collapse as the source of her insomnia.

Stress evolved as a survival mechanism to keep humans alive

Stress activates the “fight-or-flight” response when we face threats. It’s triggered by the hypothalamus, which signals the release of adrenaline and cortisol, heightening awareness and energy. While acute stress helps in short bursts, chronic stress—persistent over time—can harm both physical and mental health, leading to conditions like hypertension, anxiety, or depression.

Famed psychologist Sigmund Freud believed dreams were symbolic expressions of desire.

A near-death experience is a phenomenon reported by roughly 5% of the population, typically occurring after a traumatic physical event or a brief clinical death.

People with a sleep disorder called REM Sleep without Atonia don't experience the temporary paralysis of skeletal muscles that typically occurs during REM sleep—instead, they have vivid dreams that they act out during sleep.

Sleep is no longer considered a binary state—scientists are seeking to map a variety of liminal states between sleep and waking, including the hypnagogic state associated with boosts of creativity.