What Causes Nightmares and How to Prevent Them

Jonathan Warren

Author: Jonathan Warren



What causes nightmares and how to prevent them 

We can start experiencing nightmares from as early as two years old, and for some of people they continue to play a part in our sleep pattern throughout adulthood; 85% of adults experience at least one nightmare a year, and this can be much more for some individuals. At Time4Sleep we understand the importance of getting a good night’s rest and as nightmares can be disruptive to sleep, we have looked at the reasons behind why nightmares occur and what we can try and do to prevent them. 

Why do we have nightmares? 

Although they sound similar, there is a distinct difference between bad dreams and nightmares. Bad dreams often occur as part of a night’s sleep, but they pass without causing disturbance. Nightmares, on the other hand, are closely linked to strong sensations of stress and fear. These feelings can lead to a poor night’s sleep and ultimately a feeling of fatigue and general grogginess the next day.  

Nightmares in both adults and children and are most likely to occur during the Rapid Eye Movement (REM) stages of sleep, otherwise known as deep sleep. We progress from slight sleep into a state of REM throughout the night, which is people tend to experience nightmares in the small hours of the morning. 

It is difficult to pinpoint exactly why we have nightmares and weird dreams, however there are certain factors that are widely believed to contribute to nightmares. These range from eating before we go to bed through to more complex psychological issues. 

Popular theories as to why we have nightmares include: 

  • Stress and anxiety in our day-to-day lives 
  • A one-off traumatic incident such as an accident or being attacked 
  • Consumption of media such as scary films and television programmes 
  • Our own imagination 
  • Medication 
  • Our sleeping environment 
  • Mental health such as depression 
  • Eating before bed 

Garden nightmares versus post-traumatic nightmares 

They key to understanding the cause of a nightmare is to first break down what type of nightmare it is you are having. There are two categories; garden nightmares and post-traumatic. 

Garden nightmares are created purely in our imagination and are as a result, bear little-to-no resemblance to real life. Nightmares where you are being chased by a mythical character or are situated in a fantasy world are classed as garden nightmares.  

Post-traumatic nightmares are linked to a specific event which has happened in a person’s life. These nightmares play back the event to the individual while they sleep. The trauma is often amplified in the nightmare and can be extremely distressed.  

The main difference between these types of nightmare (other than one being fiction and one being fact) is the after effect. Garden nightmares are generally unpleasant at the time, but when we wake up and realise that it was a nightmare, there is a sense of relief and the unpleasant feelings subside. Those who suffer from post-traumatic nightmares do not get a sense of relief as the nightmare causes them to continue reliving a traumatising event. This type of nightmares can prevent an individual from recovering psychologically from the trauma that they experienced.  

Why do I keep having weird dreams? 

Although garden nightmares seem more closely related to our imagination than they are to real life, there are many who believe that what we dream about is related to things that are going on in our lives. By linking life-fact with dream-fiction we can start to unravel what causes recurring nightmares which can help understand how to stop nightmares from even starting.  

Linking a recurring nightmare to reality is difficult as there is no obvious link between the fictional nightmare and a specific event that has occurred. However, there are widely accepted ideas behind the cause of specific recurring nightmares which could be the first step to you understanding what causes recurring nightmares.  

We have collated some of the most widely reported nightmare themes and their potential triggers to help those of you who are stuck in a cycle of constantly having bad dreams. 

Teeth falling out 

If you have ever woken up in a cold sweat with the vivid memory of losing all your teeth, you’re not alone; having your teeth fall out is actually a very common nightmare. 

There are two main interpretations for this nightmare. The first looks at how from the beginning of humankind our teeth have been one of our most powerful tools. Losing them in our dreams is therefore associated with a feeling of a loss of power which, in turn, has also been linked to a feeling of lacking in self-confidence. 

The second interpretation of this nightmare scenario stems from a potential lack of self-worth and worries of how we come across to other people.   


Whether it’s falling off a building or falling in the street, the ‘falling’ theme is another common nightmare to have. It’s widely thought that the act of falling and the fear associated with it in our nightmares is caused by anxiety triggered by a stressful situation. This might be anxiety caused by a single event, or anxiety which has built up over a long period of time. If you’re suddenly experiencing nightmares where you fall, it may be worth looking at your levels of anxiety and stress.  

Being chased 

Being chased, along with an inability to flee, is often interpreted as the dreamer feels that they are struggling to pursue a life goal. Didn’t get the interview you were hoping for? Is your own business struggling to take off? All these personal ambitions and what you perceive as inability to achieve them can be related to this nightmare. 

How to stop having nightmares every night 

Pinpointing the trigger of your nightmares is the first step to preventing them from happening repeatedly. If your nightmares are being brought on by a traumatic life event or you suspect they’re happening because you’re going through a stressful and anxious time, then talking through the problem with friends, family and medical professionals is a good place to start.  

You can also reduce the likelihood of nightmares by making small tweaks to your nighttime routine and environment. This is particularly useful if you are unable to pinpoint the cause of your nightmares or suffer from them infrequently. 

Ways you can improve your sleep hygiene to reduce the frequency of nightmares include: 

  • Avoiding eating immediately before bed - and we don’t just mean cheese! Fatty foods, high carbohydrate foods and yes, even your night-time glass of red can all contribute to a restless night sleep and make it more likely you will suffer from bad dreams 
  • There’s truth in the saying ‘tidy environment, tidy mind’. While fictional, garden nightmares gain inspiration from your environment so you may find that the pile of clothes on the window ledge transforms into the boogie man. Making sure your bedroom is clean, tidy and de-cluttered can go a long way towards being able to shut your mind down for the evening 
  • Putting your phones and tablets down at least two hours before bed. While this seems like an impossible task to some, giving your eyes and mind a rest from the blue light and the non-stop screen activity gives yourself a great chance of a peaceful night’s sleep  
  • Make a list of any worries or troubles you have. This can help declutter your mind and prevent these issues from transforming into nightmares 

Hopefully our tips on understanding why we have nightmares and what we can do to prevent them will help you get the restful night’s sleep you need. If you have any other tips for preventing weird dreams please drop them in the comments below! 

References 1.: https://amerisleep.com/blog/avoiding-nightmares/