Do dreams mean anything? What research says about dream interpretation

“Dreaming that your teeth fall out is a bad omen”: you may well have heard something like it. In Korean folk tradition, a dream of losing teeth has been read as an ill omen that someone in the family will die, and dreams of pigs, water or blood carry meanings of their own (Yoon & Lee, 2011). So do dreams really hold hidden meanings? This guide answers that question with research from psychology and sleep science.

The short answer is that many studies have looked for meanings of common dreams that hold for everyone, but they have not yet produced consistent results (Yoon & Lee, 2011), and researchers note that what typical dreams mean has not yet been answered (Schredl et al., 2004). Why we dream has no settled answer either: several theories compete, each explaining a different side of dreaming (Nir & Tononi, 2010). Research does show some things, though. What we dream reflects waking life to some degree (Schredl & Hofmann, 2003), some dreams, such as falling or being chased, were common in all four countries compared in one study (Yoon & Lee, 2011), and people tend to give more weight to dreams that fit what they already think (Morewedge & Norton, 2009).

This guide covers the theories of why we dream, how dreams relate to daily life, how common typical dreams are and what research found about dreams of losing teeth, why dream interpretations feel right, the treatment that helps with frequent nightmares, and how to enjoy dream talk without taking it as an omen. mind.io does not offer a dream interpretation test or a dream dictionary. Research on other readings, such as blood types, zodiac signs, face reading and Chinese zodiac animals, is set out in the blood type guide, the zodiac sign guide, the face reading guide and the Chinese zodiac guide.

Systematic research on dreams is fairly recent (Nir & Tononi, 2010). When REM sleep was first told apart from non-REM sleep, studies found that 74–80% of awakenings from REM sleep produced vivid dream recall, against only 7–9% from non-REM sleep. For a while dreaming was therefore thought to happen only in REM sleep, but when the question changed from “did you dream?” to “tell me anything that was going through your mind just before you woke up”, 23–74% of non-REM awakenings produced reports of some experience. Equating REM sleep with dreaming is now described as incorrect, or at best an oversimplification (Nir & Tononi, 2010). A 2017 study likewise found that in both REM and non-REM sleep, moments when people reported dreaming went with less slow brain-wave activity in regions at the back of the brain (Siclari et al., 2017).

There are several theories of why dreams happen. The “activation-synthesis hypothesis”, put forward in 1977 by Allan Hobson and Robert McCarley, held that during REM sleep the brainstem activates the brain automatically and the forebrain weaves a dream by matching those signals with information stored in memory (Hobson & McCarley, 1977). Hobson’s later model, which builds on it, sees the content of individual dreams as nearly random, while allowing that the process of interpreting the signals may carry some psychological meaning (Nir & Tononi, 2010). There is a counter-argument: citing cases in which damage to a particular forebrain pathway abolishes dreaming while leaving REM sleep intact, it holds that dreaming and REM sleep are controlled by different brain mechanisms (Solms, 2000).

The threat simulation theory places the biological function of dreaming in simulating threatening events, as a rehearsal for noticing and avoiding threats (Revonsuo, 2000). In the surveys of students and sleep-disorder patients run by researchers who challenged the theory, dreams of being chased or pursued were among the three most common themes, which fits it. But many of the most common themes were positive, such as sex or flying, or concerned present-day rather than ancestral worries, such as schoolwork, and clearly ancestral threats such as snakes or earthquakes were not common at all (Germain et al., 2000).

Other research links dreaming to the way the brain handles memories and emotions. In an experiment in which 99 college students learned a virtual maze and then either napped or stayed awake, the 4 of the 50 nappers whose dream reports mentioned the maze improved about ten times more when retested 5 hours later than nappers whose reports did not. Thinking about the maze while awake was not linked to such gains. The researchers did not claim that dreaming consolidates memory; they suggested that dreams may reflect the memory processing that goes on during sleep (Wamsley et al., 2010). Another proposal is that REM sleep reprocesses emotional memories overnight, adjusting how strongly we react the next day (Walker & van der Helm, 2009).

Some researchers do not think dreams have a function at all. As Nir and Tononi summarise them, researchers such as Foulkes and Domhoff see dreaming as what happens when the mature brain is well activated but cut off from the outside world, drawing on memories and knowledge to simulate the world, and hold that dreams have coherence and meaning but probably no function (Nir & Tononi, 2010). Each theory explains part of dreaming, but none has become the accepted account, and researchers still debate the function and meaning of dreams (Morewedge & Norton, 2009). Mark Solms wrote that “the biological function of dreaming remains unknown” (Solms, 2000, cited in Nir & Tononi, 2010).

The idea that dream content is continuous with waking life is called the “continuity hypothesis”. Schredl and Hofmann noted that empirical studies largely support it. In their own study, which combined two weeks of dream diaries with records of waking activities, people who spent more time on an activity tended to dream of it more often, although not every area showed a clear link (Schredl & Hofmann, 2003).

Waking life is not copied over as it is, though. In the same study, highly focused activities such as reading and writing rarely appeared in dreams, and the researchers concluded that the continuity hypothesis in its present vague form is not valid and needs to be stated and tested more specifically: which experiences enter dreams, and under what conditions (Schredl & Hofmann, 2003). In a study of dreams after many hours of the computer game Tetris, dreams were not a replay of the day (Nir & Tononi, 2010), and in the maze experiment, the dream reports that mentioned the maze were not re-runs of it but fragments and associations linked to it (Wamsley et al., 2010).

Worries and emotions can show up in dreams too. In a survey of 1,718 people (747 of them young people) during the COVID-19 pandemic, COVID-related anxiety was associated with how often people had nightmares and how distressing they were, which the researchers read as support for the continuity hypothesis (Remedios et al., 2023). In Finnish surveys of adults in 1972 and 1977, men who had fought at the front in the Second World War reported nightmares more often than men who had not (Sandman et al., 2013). Because most of these studies used surveys to look at associations, they cannot show that worry causes nightmares.

In short, there is evidence that dreams reflect, to some extent, what has been on our minds and what we have been through. But that is a loose link between life and dreams, not a sign that each symbol in a dream carries a set message. Nir and Tononi also note that it is difficult to predict the contents of specific dreams (Nir & Tononi, 2010). If your dreams seem to carry stress, you can check how worn out you are with the burnout self-check. It does not judge anything from your dreams.

Dreams differ from person to person, but there are also “typical dreams” that many people share. Researchers have measured how common they are with the Typical Dreams Questionnaire (TDQ), which asks whether people have ever had each of 55 dream themes (Yoon & Lee, 2011). In a study that gave the questionnaire to 1,181 first-year university students in three Canadian cities, the profile of themes varied little by age, gender or region (Nielsen et al., 2003), and in a study of 444 participants, most people had experienced most of the 55 themes at least once in their lives (Schredl et al., 2004).

In Korea, researchers at the Catholic University of Korea translated the questionnaire and gave it to 500 adults aged 18 to 63 (187 men and 313 women). The sample was gathered through the researchers’ acquaintances, so it does not represent Koreans as a whole. The dreams most people had experienced were falling (80.6%) and being chased or pursued without being hurt (78.4%), followed by being about to fall (74.0%) and sexual experiences (68.4%). Flying or soaring came to 63.0%, school, teachers or studying to 62.4%, teeth falling out or going missing to 57.2%, and failing an exam to 44.4%. More women (66.1%) than men (42.2%) had dreamt of losing teeth (Yoon & Lee, 2011).

The same paper compared these figures with studies from other countries. Being chased was reported by 81.5% in Canada, 92.2% in China and 88.7% in Germany, and falling by 73.9%, 87.1% and 74.3%. Falling, being chased, sexual experiences, school and studying, and flying ranked near the top in all four countries. Dreams of losing teeth, by contrast, were less common than in Korea (57.2%): 18.8% in Canada, 35.6% in Germany and 49.4% in China (Nielsen et al., 2003; Schredl et al., 2004; Yu, 2008; all cited in Yoon & Lee, 2011). But the Canadian and German studies asked for a yes or a no while the Chinese and Korean ones used a 5-point scale, and the other studies surveyed university students while the Korean one surveyed adults in general, so the figures cannot be compared one for one (Yoon & Lee, 2011).

So do common dreams share a meaning? Schredl and colleagues wrote that what these themes mean, and how they relate to waking experience, has not yet been answered (Schredl et al., 2004). Many studies have looked for meanings that hold for everyone without reaching consistent results, and even a dream of flying has been read by some scholars as a sexual wish and by others as high ambition (Yoon & Lee, 2011).

One study looked at dreams of losing teeth directly. In a survey of 210 university students in Israel, dreams of teeth falling out or rotting were linked to waking up with tension or tenderness in the teeth, gums or jaws (r = 0.21) but not to psychological distress (r = 0.02), while dreams of falling were weakly linked to distress (r = 0.13). The researchers suggested that teeth dreams may come less from symbolism than from sensations in the mouth during sleep working their way into the dream, but because this was a preliminary study at a single point in time, it cannot separate cause from effect, and the dreams might even lead people to clench their teeth; more research is needed (Rozen & Soffer-Dudek, 2018).

The belief that dreams hold hidden meanings showed up in student surveys in three countries. Researchers from Carnegie Mellon and Harvard showed students four theories of dreaming without their names and asked which was most true. The Freudian account, that dreams reveal hidden truths when emotions buried in the unconscious surface in disguised form, was chosen by 56% of 50 students at MIT in the United States, 64.9% of 57 students at Korea University and 73.8% of 42 students in New Delhi, India. The theories that dreams help solve problems, that they throw out unwanted information to help learning, or that they are a by-product of brain activity were chosen less often (Morewedge & Norton, 2009).

The belief also shaped judgement. In an experiment in which 182 commuters in Boston imagined the night before a flight, those who imagined dreaming that the plane crashed said it would sway their travel plans more than those who imagined thinking the same thing while awake or hearing a government terror warning, and imagining a real crash on the route did not sway them more than the dream. These were answers about how people felt about flying, not observed behaviour. People also gave more weight to dreams that fitted what they already thought. Pleasant dreams about people they liked were seen as more meaningful, and so, relatively, were unpleasant dreams about people they disliked, and a dream in which a friend kissed their partner was seen as less meaningful than one in which the friend protected them from someone trying to hurt them. The researchers concluded that people interpret their dreams in a motivated way, leaning towards what they want to believe (Morewedge & Norton, 2009).

Familiar habits of mind also make a dream feel as if it “came true”. In a small survey, 68% of 81 Boston commuters believed dreams foretell the future and 63% said at least one of their dreams had come true (Morewedge & Norton, 2009). Confirmation bias, remembering the moments that match what we expect and letting the others slip by, means that the one dream that came true stays in memory, while the many dreams followed by nothing are easily forgotten. If a dream reading is worded like “a change is coming”, which fits almost anyone, the Barnum effect adds to it. In 1949 the psychologist Bertram Forer handed his students what he said were individually written personality sketches, which were in fact all the same text, and the students rated it as a good fit for themselves (Forer, 1949).

In 1900, in The Interpretation of Dreams, Freud described dreams as unacceptable unconscious wishes that surface in disguised form after censorship and distortion, and believed that interpreting them could be used in therapy. Jung also used dreams in therapy, but he did not see them as disguised wish fulfilment; he saw them as the archetypes of the unconscious showing themselves openly (Yoon & Lee, 2011). Today Freud’s view is treated as one position among several, and it is judged weak at explaining dreams that everyone has, such as flying or losing teeth (Nir & Tononi, 2010). The dream researcher G. William Domhoff concluded that because a considerable body of systematic evidence contradicts the key claims of Freud’s dream theory, most dream researchers do not consider it viable; some researchers, such as Solms, are trying to revive parts of it through the brain mechanisms behind dreaming (Domhoff, 2004).

Korean dream reading (haemong) is part of folk tradition (Yoon & Lee, 2011). It is a traditional reading, not a validated prediction. Since even research looking for shared meanings of common dreams has not produced consistent results (Yoon & Lee, 2011), it is hard to accept that any dream carries a fixed good or bad omen.

Nightmares are not rare. In Finnish surveys from 1972 to 2007 that asked 69,813 adults aged 25 to 74 whether they had had nightmares in the past 30 days, 3.5% of men and 4.8% of women said “often”, and 36.2% of men and 43.5% of women said “sometimes”. The researchers explain that occasional nightmares unrelated to trauma are usually completely benign, while frequent nightmares may cause considerable distress (Sandman et al., 2013).

When nightmares keep coming back and cause distress or get in the way of daily life, they may be a sleep disorder called nightmare disorder. The International Classification of Sleep Disorders (ICSD-3) describes repeated, long, extremely unpleasant and well-remembered dreams that usually involve threats to survival or safety, quick alertness on waking, and distress or impairment such as low mood, fear of going to sleep, or daytime sleepiness and fatigue. Nightmare disorder affects 4% of adults in the United States. It is associated with depression and anxiety, and up to 80% of people with post-traumatic stress disorder (PTSD) report nightmares (Morgenthaler et al., 2018). Only a professional can make a diagnosis. If you were awake but could not move and felt someone in the room, that is closer to sleep paralysis than to a nightmare.

If you notice these signs, talk to a sleep specialist or a mental health professional rather than looking for the meaning of the dreams; your family doctor is a good place to start. That means nightmares frequent enough that you dread going to sleep, daytime sleepiness and exhaustion, or nightmares that unsettle your mood and daily life (Morgenthaler et al., 2018). If nightmares have followed something terrible that happened to you, see also the guide to trauma and PTSD. Some medicines can cause nightmares, and stopping some medicines can bring them on too (Morgenthaler et al., 2018). Mention any medicine you have recently started or stopped, and do not stop a prescribed medicine on your own: talk to the doctor who prescribed it first.

There is a treatment for nightmares with proven benefits. The American Academy of Sleep Medicine recommends imagery rehearsal therapy for both PTSD-associated nightmares and nightmare disorder. While awake, you rewrite the nightmare into a new, more positive version and rehearse it in your mind for 10–20 minutes a day; nine randomised controlled trials have looked at its effects. Not every trial found a benefit: in 124 Vietnam veterans with chronic PTSD, it did no better than standard therapy with the same amount of therapist contact. Because many treatments have limited evidence, the Academy issued a position paper rather than a clinical guideline, and it classed treatments such as cognitive behavioural therapy, progressive deep muscle relaxation and lucid dreaming therapy as ones that “may be used” (Morgenthaler et al., 2018). The World Sleep Society endorsed the position paper in 2025 (Provini et al., 2025). Imagery rehearsal therapy is done with a professional.

If stress is building up and unsettling your sleep, see also how to relieve stress and insomnia: what helps.

Dreams make good stories, and there is nothing wrong with enjoying talking about them. Rather than making important decisions on a dream reading, though, using a dream as a prompt to look at how you have been feeling fits the research better. Since dreams reflect daily life and concerns to some degree (Schredl & Hofmann, 2003), asking “what has been on my mind lately?” may be more useful than asking “what does this dream foretell?”

If an ominous dream is weighing on you, remember the experiment in which people who merely imagined a dream of a plane crash said it would sway their travel plans as much as imagining a real crash (Morewedge & Norton, 2009). The unease a dream leaves is real, but it is not evidence that the dream foretells anything. The same goes for good dreams: enjoying them as a pleasant story is enough.

Lucid dreams, in which you realise you are dreaming while still in the dream, are not rare either. A meta-analysis of research from 1966 to 2016 estimated that 55% of people have had at least one lucid dream (34 studies) and 23% have them once a month or more (25 studies) (Saunders et al., 2016). Lucid dreaming therapy is one of the treatments that “may be used” for nightmare disorder, but it is not recommended in the way imagery rehearsal therapy is (Morgenthaler et al., 2018).

If you often dream of losing teeth and wake up with your teeth or jaw feeling tense, that tension is listed among the signs of grinding or clenching your teeth during sleep (Rozen & Soffer-Dudek, 2018). Asking a dentist or a sleep specialist about it may help more than decoding the dream.

Q. Can I trust dream interpretation? A. Many studies have looked for meanings of common dreams that hold for everyone, without consistent results, and even a dream of flying has been read in different ways (Yoon & Lee, 2011). Researchers also note that what typical dreams mean has not yet been answered (Schredl et al., 2004). Enjoy dream readings as tradition, but it is better not to base important decisions on them.

Q. What does it mean to dream that your teeth fall out? A. Korean folk tradition has read it as an ill omen that someone in the family will die, but that is a traditional reading. It is a common dream: 57.2% of 500 Korean adults surveyed had had it (Yoon & Lee, 2011). In a preliminary study of 210 university students in Israel, it was linked to waking up with tension in the teeth or jaw, not to psychological distress (Rozen & Soffer-Dudek, 2018).

Q. Why do I dream of falling or being chased? A. No single cause has been established. In the Korean survey of adults, 80.6% had dreamt of falling and 78.4% of being chased, the two most common themes (Yoon & Lee, 2011). The threat simulation theory explains threatening dreams such as being chased as a rehearsal for danger, but it is one theory among several (Revonsuo, 2000). In the Israeli student study, dreams of falling were weakly linked to psychological distress (Rozen & Soffer-Dudek, 2018).

Q. I hardly ever dream. Do some people not dream at all? A. Some people say they rarely dream, but when researchers wake people systematically in sleep laboratories, it turns out that we greatly underestimate how often we experience something during sleep. Adults woken from REM sleep report dreaming 80–90% of the time (Nir & Tononi, 2010). Not remembering dreams and not dreaming may be two different things.

Q. Should I see a doctor if I often have nightmares? A. Occasional nightmares unrelated to trauma are usually benign (Sandman et al., 2013). But if they are frequent enough that you dread going to sleep, leave you sleepy and worn out during the day, or upset your mood and daily life, talk to a sleep specialist, a mental health professional or your family doctor. There is a treatment with proven benefits, imagery rehearsal therapy (Morgenthaler et al., 2018). If they began after something terrible happened to you, see also the guide to trauma and PTSD.

Q. Can dreams predict the future? A. Many people believe so: in a small survey, 68% of 81 Boston commuters believed dreams foretell the future (Morewedge & Norton, 2009). But dreams that come true stay in memory while the ones that miss are easily forgotten, so the feeling that a dream came true is not enough to say that dreams can foresee events. Likewise, the feeling during déjà vu of knowing what comes next did not lead to real prediction in experiments (Cleary & Claxton, 2018).

Q. Is there a dream interpretation test? A. mind.io does not offer a dream interpretation test or a dream dictionary. If you want to know how worn out you are, try the burnout self-check, and for sleep problems see insomnia: what helps. The burnout self-check looks at exhaustion through your own answers, not your dreams.

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