Quick Answer: Crying in sleep is usually caused by emotionally intense dreams during REM sleep, when the brain processes feelings and memories. It is common and typically harmless in adults and children. However, frequent crying during sleep alongside other symptoms such as nightmares, night terrors, or mood changes during the day may warrant a conversation with a doctor, as it can occasionally signal depression, PTSD, or a sleep disorder.
In This Guide
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Waking up to find tears on your cheeks, or discovering that your partner has been crying in their sleep, can be unsettling if you do not know what to make of it. It happens more often than most people realise. And for the most part, it is a normal part of how the sleeping brain processes emotion.
That said, "normal" does not mean it should always be ignored. Understanding the causes helps you tell the difference between ordinary emotional processing and something that might benefit from attention.
This article covers the science of why it happens, the most common causes, what it looks like in children versus adults, and when it makes sense to talk to a healthcare provider. We will also look at how sleep quality, including mattress comfort, affects the emotional aspects of sleep in ways most people do not consider.
Note: This article is for general information only. It is not medical advice. If you have concerns about your own sleep or your child's, please consult a qualified healthcare provider.
Why Do People Cry in Their Sleep?
The short version: your brain does not fully stop processing emotion when you fall asleep. During certain stages of sleep, particularly REM (Rapid Eye Movement) sleep, emotional memories are actively consolidated, replayed, and processed. If that processing involves intensely sad, frightening, or emotionally charged content, the physical response, including tears, can happen spontaneously.
In most cases, the person crying in sleep is dreaming. The dream content may be sad, frightening, or emotionally overwhelming, and the body responds as if the experience were real. Tears are simply one of those physical responses, alongside elevated heart rate, changes in breathing, and occasional vocalisation.
Less commonly, crying during sleep can occur without conscious dreaming, as part of night terrors, parasomnias, or in response to physical discomfort. We will cover each of these below.
REM Sleep and Emotional Processing
To understand why crying in sleep happens, it helps to understand what REM sleep is doing.
REM sleep accounts for approximately 20-25% of total sleep time in healthy adults and occurs in cycles throughout the night, with the longest REM periods in the final hours before waking. It is the stage most associated with vivid dreaming. During REM, the brain is highly active, with activity patterns similar to wakefulness, but the body is essentially paralysed (a state called atonia) to prevent acting out dreams.
One of REM sleep's core functions is emotional memory consolidation. Research by Matthew Walker at the University of California, Berkeley, and others has established that REM sleep allows the brain to replay emotionally charged memories in an environment where the stress hormone noradrenaline is suppressed. This "safe replay" allows emotional content to be processed and recontextualised without the full distress of the original experience.
The REM "Overnight Therapy" Theory
Dr. Matthew Walker describes REM sleep as a form of overnight emotional therapy. During REM, the brain strips the emotional charge from difficult memories while preserving the factual content. This is why events that felt overwhelming the day before often feel more manageable in the morning. When this process involves particularly difficult emotional content, the physical responses of crying, rapid breathing, or vocalisation can cross the threshold from internal experience to external expression. For people going through grief, major life transitions, or high stress periods, vivid emotional dreams and associated physical responses are especially common.
The implication is important: crying during REM sleep is often a sign that the brain is doing its job well, not a sign that something is wrong. Emotional processing during sleep is associated with better mental health outcomes, not worse ones. People who are deprived of REM sleep often show greater emotional reactivity and more difficulty regulating difficult feelings during the day.
Common Causes of Crying During Sleep
While emotional dreaming is the most common cause, there are several distinct reasons someone might cry in their sleep, and they range from completely benign to worth investigating.
Emotionally Intense Dreams
The most common cause by far. A dream involving loss, conflict, fear, or grief can trigger real tears even without the dreamer becoming aware they are crying. Many people who wake with tear-stained cheeks have no memory of the dream that caused it. The intensity of REM dreams typically increases in periods of stress, grief, major life change, or illness.
Night Terrors (Sleep Terrors)
Night terrors are distinct from nightmares and occur during non-REM sleep, usually in the earlier part of the night. They are characterised by sudden partial arousal with intense fear, screaming, crying, or thrashing. The person appears awake and distressed but is not fully conscious and typically has no memory of the episode in the morning. Night terrors are more common in children but can occur in adults, particularly in periods of sleep deprivation or high stress.
Grief and Bereavement
Grief commonly affects dream content and emotional sleep responses. Many people who have lost a loved one report dreams in which the person appears, sometimes joyfully and sometimes in distressing circumstances. Waking with tears after such dreams is very common and is generally part of normal grieving. Dreams of deceased loved ones can also be a source of comfort and are often described as deeply meaningful by those who experience them.
Depression and Anxiety
Both depression and anxiety can significantly affect sleep architecture and dream content. People with depression tend to enter REM sleep earlier and spend more time in it, which is associated with more intense emotional dreaming. Persistent crying during sleep, combined with other symptoms like fatigue, low mood, loss of interest, or excessive worry during waking hours, may be a signal that depression or anxiety warrants professional attention.
PTSD and Trauma
Post-traumatic stress disorder is associated with vivid, intrusive nightmares that replay traumatic content. These nightmares are often accompanied by physical responses including crying, elevated heart rate, and sweating. PTSD-related nightmares are a diagnostic criterion for the condition and are very effectively treated with specific therapies (Image Rehearsal Therapy, EMDR) and, in some cases, medication. If traumatic nightmares are frequent and affecting quality of life, this is an important reason to speak with a doctor.
Physical Discomfort
Pain, digestive discomfort, or physical illness can influence dream content and cause distress responses during sleep, including crying. If someone consistently cries during sleep and also has ongoing physical symptoms, addressing the physical cause may resolve the sleep symptom. An uncomfortable mattress that creates pressure point pain or misaligns the spine can be a subtle but persistent source of physical discomfort during sleep.
Certain Medications
Some medications affect REM sleep and dream intensity. Beta-blockers, antidepressants, some blood pressure medications, and certain antivirals have been associated with more vivid or emotionally intense dreams. If crying in sleep began after a medication change, this is worth mentioning to your prescribing doctor.
Dorothy, Sleep Specialist: "We talk about this less than we should. Sleep is when the mind does its hardest work. A lot of the emotional weight people carry gets sorted out during the night, and sometimes that process has a physical expression. What I tell people is to pay attention to the pattern, not just a single incident. One emotional night is usually nothing. Weeks of disrupted emotional sleep is worth looking at."
Crying in Sleep in Babies and Children
Crying during sleep in infants and young children is extremely common and has some distinct characteristics worth understanding.
Infants (0-12 months)
Newborns spend approximately 50% of their sleep time in a state analogous to REM sleep, compared to 20-25% in adults. During this active sleep phase, you will commonly see infants smiling, frowning, twitching, making vocalisations, and yes, crying briefly without waking. This is entirely normal and is not a sign of distress. Infants also have brief night wakings between sleep cycles that are normal and typically not cause for concern if the infant returns to sleep on their own.
If an infant is crying persistently and cannot be settled, other causes such as hunger, discomfort, illness, or colic should be considered. Consult your paediatrician or your local Public Health Nurse if you have concerns about your baby's sleep or night crying patterns.
Toddlers and Young Children
Toddlers and young children are more prone to night terrors than older children or adults, with peak prevalence between ages 2 and 6. A toddler experiencing a night terror will appear awake and distressed, may cry or scream, and will be difficult to console. The episode typically resolves on its own within a few minutes, and the child will usually return to sleep with no memory of the event.
Night terrors in children are associated with sleep deprivation, irregular sleep schedules, stress, and fever. They are not associated with psychological problems and typically resolve on their own as the child's sleep architecture matures. The most helpful response is to ensure the child's safety and wait calmly for the episode to pass rather than trying to wake them.
Normal vs. Concerning Sleep Crying in Children
The Canadian Paediatric Society notes that brief night wakings and vocalisations are a normal part of infant sleep cycles. Consistent night terrors in older children (over age 8), particularly if accompanied by daytime anxiety or behavioural changes, may benefit from an evaluation. Similarly, nightmares that are severe, frequent, and causing the child to resist bedtime are worth discussing with a paediatrician. For most children, improving sleep hygiene, including consistent bedtimes, a calming pre-sleep routine, and an age-appropriate sleep environment, significantly reduces night-time crying and distress.
When to Seek Help
Most crying during sleep does not require medical attention. However, there are specific situations where it makes sense to consult a doctor or sleep specialist.
Signs That Crying in Sleep Warrants Medical Attention
- Frequent nightmares with traumatic content: Especially if related to a specific traumatic event
- Night terrors in adults: Particularly if accompanied by sleepwalking or other parasomnias
- Emotional crying during sleep paired with daytime symptoms: Including persistent low mood, anxiety, or fatigue that does not improve with rest
- New onset after medication change: Report to your prescribing doctor
- Child over age 8 with frequent night terrors: Especially if daytime behaviour is also affected
- Sleep disruption affecting daily functioning: If you or your partner's sleep crying is consistently waking you both and affecting daytime quality of life
Your family doctor is the appropriate first point of contact. They can assess whether referral to a sleep specialist, psychologist, or psychiatrist is indicated, and can rule out physical causes like sleep apnea that can affect sleep quality and dream patterns.
Sleep Quality and Emotional Resilience
Here is something worth understanding: the quality of your sleep affects your emotional processing capacity, and your emotional load affects the quality of your sleep. They are bidirectional. Poor sleep does not just leave you tired. It measurably reduces your capacity to regulate difficult emotions the following day.
Multiple studies have found that sleep-deprived people show heightened amygdala reactivity, meaning the brain's emotional alarm centre becomes more sensitive and harder to regulate. This creates a cycle: emotional difficulty disrupts sleep, disrupted sleep amplifies emotional difficulty, which further disrupts sleep.
One practical implication of this is that anything that improves overall sleep quality also indirectly improves your ability to process emotional content during sleep. A mattress that keeps you sleeping deeply through the night, rather than waking you from pressure points or motion transfer, gives your brain more uninterrupted time in the deeper sleep stages, including REM, where emotional processing happens.
In Brantford, we often see people who have been sleeping poorly for years on a mattress that is no longer supportive. They have adapted to waking frequently and assume it is just how they sleep. When they switch to a mattress that genuinely fits their body, the improvement in sleep depth is often noticeable within days, and the emotional benefits, feeling more regulated, more resilient, and better equipped to handle difficult feelings, tend to follow. If you are curious about what a better mattress might do for your sleep, our guide on mattress lifespan can help you assess whether yours is still doing its job.
Sleep position and pillow support also affect how deeply you sleep. If you wake frequently due to neck pain or shoulder discomfort, those interruptions are fragmenting the sleep cycles during which emotional processing happens. Our pillow guide for side sleepers and pillow guide for back pain cover how to choose the right support for your position.
Crying in sleep can occur during REM dreaming, stress processing, or as a parasomnia, and is more common in adults experiencing grief, anxiety, or sleep deprivation. Mattress Miracle at 441½ West Street in Brantford notes that a comfortable, supportive sleep surface helps reduce stress-related sleep disturbances. Dorothy recommends a mattress that provides both physical comfort and a sense of security for better emotional processing during sleep. Call (519) 770-0001.
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Call 519-770-0001Frequently Asked Questions
Is it normal to cry in your sleep?
Yes, it is common and usually normal. Crying during sleep most often occurs during REM sleep, when the brain is actively processing emotional memories and experiences. It typically requires no treatment unless it is frequent, distressing, or accompanied by other symptoms like daytime mood changes, fatigue, or signs of depression or anxiety.
What does it mean when you cry in your sleep without knowing why?
Most people who cry during sleep do not remember the dream that caused it. The brain processes emotionally significant content during REM sleep, and the physical response, tears, can happen without conscious awareness. It does not necessarily mean something is wrong, though frequent occurrence during stressful or grief-filled periods is very common and reflects normal emotional processing.
What is the difference between nightmares and night terrors?
Nightmares occur during REM sleep, are usually remembered clearly, and the person wakes feeling frightened but fully oriented. Night terrors occur during non-REM sleep in the earlier part of the night, involve intense fear or crying while appearing partially awake, and the person typically has no memory of the episode. Night terrors are more common in children, while nightmares are common across all ages.
Can a bad mattress cause more emotional sleep disturbance?
A mattress that causes frequent waking from pressure point pain or discomfort disrupts sleep cycles, including REM sleep, which is when emotional processing occurs. Chronic sleep fragmentation has been shown to increase emotional reactivity and reduce the brain's ability to regulate difficult feelings. While a mattress is not a treatment for emotional distress, a comfortable and supportive sleep surface does contribute to more uninterrupted, restorative sleep.
When should I be concerned about my child crying in sleep?
Brief crying or vocalisations during sleep are normal for infants and young children due to active sleep stages. Night terrors in children ages 2-6 are common and typically resolve without intervention. Seek medical advice if night terrors persist in children over age 8, if nightmares are severe and frequent enough to cause bedtime resistance, or if the child shows signs of daytime anxiety or behavioural changes alongside sleep disturbance.
Sources
- Walker, M.P., & van der Helm, E. (2009). Overnight therapy? The role of sleep in emotional brain processing. Psychological Bulletin, 135(5), 731–748. doi.org/10.1037/a0016570
- Stickgold, R. (2005). Sleep-dependent memory consolidation. Nature, 437(7063), 1272–1278. doi.org/10.1038/nature04286
- Levin, R., & Nielsen, T.A. (2007). Disturbed dreaming, posttraumatic stress disorder, and affect distress: A review and neurocognitive model. Psychological Bulletin, 133(3), 482–528. doi.org/10.1037/0033-2909.133.3.482
- Yoo, S.S., et al. (2007). The human emotional brain without sleep: A prefrontal amygdala disconnect. Current Biology, 17(20), R877–R878. doi.org/10.1016/j.cub.2007.08.007
- Canadian Paediatric Society. (2019). Healthy sleep for your baby and child. Caring for Kids. caringforkids.cps.ca
- Krakow, B., & Zadra, A. (2006). Clinical management of chronic nightmares: Imagery rehearsal therapy. Behavioral Sleep Medicine, 4(1), 45–70. doi.org/10.1207/s15402010bsm0401_4
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