Adults dream for about two hours a night, on average—that’s one-twelfth of their lives, adding up to more than six years of dreaming during an 80-year life. World literature is filled with dreams. Dreams play an outsized role in Shakespeare’s plays, above all, from Hamlet and Macbeth to The Tempest and Midsummer Night’s Dream. In Dickens’s A Christmas Carol, Scrooge tells himself that Marley’s ghost (surely a dream or apparition in a dream) might simply be “an undigested bit of beef, a blot of mustard,” and it’s true that indigestion and other physical problems can cause strange dreams. Old Testament patriarchs were dreamers on a cosmic scale: Jacob dreamed of a ladder leading up to heaven; Joseph got a job interpreting dreams for Pharaoh.
Indeed, explaining dreams has, over the centuries, been a good way to earn a living. In some societies, shamans use dreams to diagnose illness, expose adultery, predict pregnancy and the weather, or locate game. Under the influence of Sigmund Freud’s psychoanalytic theories, dreams passed into the domain of the psychiatrist, and many people undergoing analysis spend their 50 minutes unraveling their dreams. Therapists today are less likely to do dream analysis, often employing shorter-term therapies and antidepressants instead.
Dreams may seem to have little or nothing to do with physical health, but they are an integral part of sleep and thus are essential to life. “We are such stuff as dreams are made on,” as The Tempest's Prospero says, yet dreaming remains largely a mystery. That said, we’ll try to answer some dreamy questions.
Do dreams disrupt sleep?
No, dreams are a key part of restorative sleep. Sleep has four phases, which we cycle through usually four or five times a night: REM (rapid eye movement) plus three non-REM stages. Most dreaming goes on during the REM stage, when the eyes move under the lids. Dreaming may not seem particularly restful, however, especially if you have nightmares and they occur just before waking.
Does everybody dream?
Except for people with certain brain abnormalities, everyone has REM sleep, during which dreams occur. Of course, people who don’t remember their dreams may think they don’t dream, but they almost certainly do. This was the conclusion of a French study in the Journal of Sleep Research in 2015, which found that when people who claimed they never dreamed were monitored during sleep, their movements and other behavior strongly indicated they were indeed dreaming during REM sleep.
Does dreaming serve specific purposes?
Humans have long wondered why we dream and whether it serves a purpose—perhaps as a way for us to communicate with the gods, predict the future, or represent our repressed feelings. There are scores of theories. Modern dream research began with Dr. Freud, who thought dreams represented unfulfilled wishes, rooted in unresolved childhood traumas that had been repressed. Carl Jung, another famous dream theorist, thought a dream was “the small hidden door in the deepest and most intimate sanctum of the soul.”
The truth is that nobody knows for sure why we dream or whether dreams are of any use, but many functions have been proposed. For instance, studies have found that REM sleep (the dreaming stage), in particular, helps people consolidate and reorganize memories so that they can perform cognitive activities better. Other studies suggest that REM sleep may mitigate the intensity of stressful experiences, in part by reducing norepinephrine, a stress-related hormone. This was seen in a recent study in the Journal of Neuroscience, in which students learned to associate an image with a mild electric shock. Brain scans showed that those who spent more time in REM sleep prior to the experiment had reduced brain activity in response to this learned fear. The researchers suggested this may be due to the effect of REM sleep on norepinephrine.
How can you better remember your dreams?
Some people remember their dreams regularly, without effort, but most of us forget them quickly—or seldom remember them at all unless we are awakened in the middle of one. The brain processes that store memories are largely suppressed during sleep. You’re more likely to recall dreams that are more coherent as well as those that are very vivid and cause greater arousal. Therapists who want their patients to discuss their dreams may suggest various strategies to increase the chances of recalling them. For instance, remind yourself as you fall asleep that you want to remember your dreams, and keep a notebook or digital device by your bed so you can record them whenever you wake up. It may also help to record the day’s events before you fall asleep. When you wake up in the morning, try to do so gradually, in a relaxed manner, and try to hold onto your memories of your dreams, rather than jumping out of bed and getting immediately distracted. Keep in mind that when people recall and relate dreams, they inevitably shape them, tending to make them more sensible and rational by piecing snippets together and filling in gaps. There’s no way to capture a dream while it happens.
What is a nightmare?
Typically, nightmares have been seen as dreams that are frightening (like being chased by a monster) and wake people up. Today, nightmares are usually defined as intensely disturbing, rather than just very scary, dreams. It’s estimated that up to one-third of adults have at least one nightmare a month, while up to 6 percent say they experience nightmares every week. In a study in the journal Sleep in 2014, researchers analyzed the dreams of almost 600 people and found that it wasn’t fear that made nightmares so emotionally charged, but rather feelings of guilt, disgust, or sadness. Nightmares also often involve death, feeling threatened, or health concerns.
Do medications affect dreaming?
Yes. People taking certain medications may experience more vivid and intense dreams, typically in the form of nightmares. Some beta-blockers (used for hypertension) commonly do this. But the list is lengthy and also includes some antidepressants, corticosteroids (at higher doses), levodopa (for Parkinson’s disease), and mefloquine (used to prevent or treat malaria).
Some people may experience increased nightmares when they stop taking certain drugs, including benzodiazepines, barbiturates, and, again, certain antidepressants—especially if this is done abruptly, or if the dose is reduced too quickly.
In many cases, the drugs affect brain chemicals that influence REM sleep.
For tips on how to improve sleep, see 15+ Sleep Remedies.