Nightmares sleeping in bed
All of us experience nightmares, but some factors can abnormally increase the risk of having them. Image Credit: Shutterstock

The details of the dream are not clear, but even as you are snugly encased in soft blankets and pillows, you feel the world teetering dangerously… and wake up, startled.

The territory of nightmares is often unpleasant beyond measure, and it turns out that not only do some diseases and medications spur more bad dreams, certain sleep practices may too.

Humanity’s common nightmares

Nightmares are often defined as ‘repeated occurrences of extended, extremely dysphoric and well-remembered dreams that usually involve threats to survival, security or physical integrity’ and can make you wake up – as per a 2019 study by US and France-based researchers on lucid dreaming published in the Switzerland-based journal Frontiers in Psychology.

“About 25 times a year, on average, a person will experience what is known as a nightmare. These dreams cause fear and anxiety in the dreamer. They are not out of the ordinary and are experienced by almost everyone at some point or another,” says Tharaka Rani Sreekumar, clinical psychologist at Abu-Dhabi based NMC Specialty Healthcare hospital.

According to a 2014 study by Canada-based researchers in Sleep, the official journal of the global Sleep Research Society, the most common types of nightmares are those featuring physical aggression, being chased, interpersonal conflicts, environmental abnormality, evil presence, accidents, disaster/calamity, failure or helplessness, insects/vermin, health related-concerns, apprehension or worry, and others.

Dr Mohamed Elshafei, neurologist at Zulekha hospital, Dubai says, “There is a very important difference between nightmares or dreams that happened during REM stage where a person can remember most of the details, and night terrors – the patients only knows that they woke up during the sleep time with frightening history or frightening experience.”

When we dream
“Usually, our sleep passes through two main major stages – non-rapid eye movement (NREM) stage, this is the first stage, and then rapid eye movement (REM) stage. By definition, dreams occur during the REM stage,” explains Dr Mohamed Elshafei, a neurologist at Zulekha hospital, Dubai.
REM stages happen an average of three to five times a night.

9 reasons we have nightmares

Although we often link our nightmares to events in our lives, the truth is that medications, diseases or actions that disrupt our REM stage of sleep can all contribute. These are some reasons that can increase your risk of nightmares:

1. Fear, stress and anxiety disorders

“If your brain is very active, thinking, you have worries about some condition or are apprehensive for something, your brain will transform this to images and stories in dreams,” says Dr Elshafei.

A 2004 study by US-based researchers published in the Behavioural Sleep Medicine, official journal of the Society of Behavioral Sleep Medicine in US found that those with generalised anxiety disorders had significantly more bad dreams than those who didn’t.

This is as the visual images in dreams also include recent memories, images and emotions experienced – as explained in one of the main scientific theories behind our dreams. Pioneering dream researchers, Allan Hobson and Robert McCarley, had proposed a neuroscience-based activation-synthesis explanation for dreaming, where dreams are electrical brain impulses pulling imagery and thoughts from our brain at random.

2. Trauma and Post-traumatic Stress Disorder

“Recurring nightmares are a diagnostic symptom in Post-Traumatic Stress Disorder – remembrances in the form of flashbacks or nightmares,” says Dr Tulika Shukla, Dubai Health Authority certified psychiatrist at Millennium Medical Center.

A 2009 study by US-based researchers published in the journal ‘Sleep Medicine Clinics’ found that 80 per cent of people studied experiencing PTSD have frequent nightmares, and another study back in 2000 published in Comprehensive Psychiatry showed that 60 per cent of studied individuals who developed PTSD, reported having nightmares prior to the trauma.

“Most of the time, I have found that when there are issues in a person’s life – for example, PTSD, facing accidents, attacks, violence or childhood trauma – all these can also lead to nightmares in the person’s life,” says Sreekumar.

3. Some medications such as antidepressants, anxiolytic medicines and steroids

“Some antidepressants especially and anxiolytic medicines, and some proton pump inhibitors that is used too much now for gastritis, some medicines for hypertension, it can affect the stage two sleep, which is the main stage of sleep. So, this can affect the dream history and you might be getting new dreams that were not present in the past. This should be analysed,” says Dr Elshafei.

A 2003 review study by US-based researchers published in the journal Human Psychopharmacology: Clinical and Experimental, found, “Pharmacological agents affecting the neurotransmitters norepinephrine, serotonin and dopamine are clearly associated with patient reports of nightmares.”

• Beta-blockers: These are drugs that slow down the heart rhythm and lower blood pressure.

• Some antidepressants – Selective serotonin reuptake inhibitors, that affect the neurotransmitter serotonin, including Paroxetin have been linked to increased nightmares.

• Certain Alzheimer’s disease medications: Donepezil (Aricept) and rivastigmine (Exelon). A 2005 study published by German based researchers in the journal Der Nervenarzt, a German journal for neurologists and psychologists found a ‘clear-cut’ relationship between the occurrence of nightmares and an evening dose of donepezil for patients with dementia of the Alzheimer type (DAT), not a morning dose. They explain that this may be as the activation of the visual association cortex during REM sleep is enhanced by the drug.

• Certain steroids: Prednisone, methylprednisone, according to GoodRx health, a US-based healthcare information provider.

• Some antihistamines – Diphenhydramine (Benadryl), Cetirizine, Loratadine, Fexofenadine, Chlorpheniramine, Doxylamine, according to GoodRx health.

4. Suffering from migraines

A 2008 study by US-based researchers published in the Journal of Head and Face Pain showed that migraine patients had persistent nightmares of childhood more than those who didn’t suffer from the disease, but a 2021 review of previous studies in the field for the international journal Behavioural Science concluded that nightmares sometimes accompany migraines.

5. In later life, the onset of Parkinsonism, Parkinson’s, a type of dementia

“Some dreams, especially recurrent bad dreams is linked to some medical conditions like Parkinsonism,” says Dr Elshafei.

According to a 2011 review paper by University of Montreal researcher Tore Nielsen titled ‘Disturbed dreaming as a factor of medical conditions’, REM sleep behaviour disorder (during which ‘vivid and often frightening dreams’ are acted out by patients during sleep) is known to show before the onset of Parkinson’s disease, and one type of dementia.

6. Sleep deprivation and insomnia

According to Mayo clinic, “Changes in your schedule that cause irregular sleeping and waking times or that interrupt or reduce the amount of sleep you get can increase your risk of having nightmares.”

This can also include taking stimulants such as caffeine, or snacking just before bed.

In fact, a survey of almost 14,000 people in Finland published in journal, Sleep in 2015 concluded that symptoms of depression and insomnia were the strongest predictors of frequent nightmares in the dataset.

7. Horror movies and books

Nightmare watching horror movie on TV
Watching horror movies may also leave an 'enduring fright effect' and increase your chance of nightmares. Image Credit: Shutterstock

This one’s definitely not surprising, especially if you watch the movie before bed, and experience an extreme reaction to it. The latest study on the effects of horror movies - a 2021 study published in the Global Mass Communication Review that studied teenagers in a city in Punjab, India found that on average, 52 per cent of studied teenagers always experienced nightmares after a horror movie and 20 per cent more experienced it sometimes.

In a 1999 study by US-based researchers published in journal Media Psychology, 90 per cent of studied university students showed an ‘enduring fright effect’.

8. Presence of sleep apnea

“Nightmares are possibly associated with the presence of apneas and hypopneas during REM sleep,” as per a 2019 study by Saudi Arabia-based researchers published in Swiss journal, Frontiers in Neurology.

9. Nightmare disorder

“If there is continuous night terror or continuous nightmares, especially if it is affecting sleep – when the patient is scared to sleep, in that situation, there can be an intervention,“ says Sreekumar.

Nightmare disorder is when your dreams cause you severe distress and affect whether you get enough sleep, as per Mayo clinic. If you are experiencing this, you should consult a doctor.

Nightmares have been shown to lower well-being, and if yours are affecting you severely, reach out for professional help.