Why do I have nightmares? Common causes and what helps

Nightmares are bad dreams that wake you and that you remember, leaving a strong feeling of fear. They happen to children and to adults, and they tend to come towards the end of the night — unlike night terrors, which mostly affect children, appear early in the night and are not remembered. If you have one now and then, you are in very wide company: estimates suggest that somewhere between half and more than eighty per cent of adults report an occasional nightmare. And in most cases the exact reason they happen is simply unknown.

That is not an evasive answer. It is the honest one, and it is also the answer that saves you weeks of hunting for a single culprit in your own behaviour. What is known is that certain things raise the odds of a nightmare on a given night, and a few of those are within your reach.

Is having nightmares normal, or should I be worried?

For most people, nightmares become less frequent and less intense with age. The line between normal and worth-attention is not the number of nightmares itself, but what they are doing to your life. One estimate puts the share of people whose nightmares actually disrupt their sleep — what is called nightmare disorder — at two to eight per cent. That is a minority, and that is where the conversation changes.

If your nightmares are sporadic, if you wake and get back to sleep without much trouble, and if the next day runs normally, you are probably in the group where this settles on its own. Most cases improve with time, without intervention.

The practical test is not "how many did I have this month". It is "what is this taking from me".

The everyday causes, from the most common to the less obvious

Start with the banal ones, because they are the easiest to correct. Being very tired, or feeling physically unwell, counts. Sudden noises during the night count. Needing to urinate during the night counts, because it interferes with deep sleep. And having seen something that frightened you — a film, a news story, a conversation — or being stressed, anxious or worried about something counts, and counts a good deal.

Then there is the group that depends less on you. Some medicines, such as antidepressants, may be behind nightmares. Conditions that affect sleep, such as restless legs syndrome or sleep apnoea, also may. Mental health conditions, such as generalised anxiety disorder, and conditions that affect the brain, such as Parkinson's disease, appear on the same list. A serious injury can disturb sleep for four to six weeks.

Notice what is peculiar about that list: almost everything on it is something you will not fix by changing the time you eat dinner. That is why the next section is shorter than you might like.

What you can change this week

There are three concrete things the available evidence suggests, and none of them costs money.

The first is a relaxing routine before bed. This is not a vague instruction to "chill out"; it is a predictable sequence, done at the same time, that signals to your body that the day is over. Pick whatever suits you best and keep it up for weeks, not two nights.

The second is keeping a sleep diary. Note three things only: how long you sleep, how long it takes you to fall asleep, and how you feel the next day. After two or three weeks you have data, and data shows patterns that memory distorts. You might discover, for instance, that your worst stretches coincide with your heaviest work weeks — which changes what makes sense to try next.

The third is dealing with what is stressing you. It sounds obvious and it is the hardest of the three, but it is also the one the evidence puts at the centre. If the stress is chronic, no bedtime ritual will compensate for it.

A note on regularity: an irregular sleep schedule raises the risk. That means reasonably stable times for going to bed and getting up, weekends included. It does not mean sleeping longer to make up for it — too little sleep and being overly tired weigh in as well.

What tends not to help

Here we need to be direct, because there is a lot of popular advice that does not have behind it what people attribute to it. In the facts available, there is nothing to support the idea that a specific bedtime drink, a tea, a food or a sleeping position resolves recurring nightmares. If someone promises you that, ask them for the basis.

There is also no support for treating a single nightmare as a symptom of something serious. Most people have them and have no illness at all. Anxiety and stress are, according to the NHS, factors that can increase the risk of nightmares.

And finally, avoiding sleep is not a strategy. Putting off bedtime so as to "not have" the nightmare usually makes the tiredness worse, and tiredness is on the list of factors that raise the risk.

Where supplements honestly fit

This is the point where many pages oversell, so let us be precise: supplements do not treat nightmares, and nothing we know allows anyone to say they prevent them. Anyone telling you that melatonin puts an end to nightmares is going beyond what is known.

So where does that leave you? If your problem is falling asleep late and your schedule is out of sync, and you want to try melatonin, there is one product that can be named here: Sleep Well Gummies, 2 gummies a day for adults, shortly before bedtime, with 1 mg of melatonin per dose. They are chewed. The label warnings matter: do not exceed the recommended daily dose; not recommended for children, pregnant or breastfeeding women; in case of illness or use of medication, consult a healthcare professional before use; may cause drowsiness, so avoid driving or operating machinery after taking; contains polyols, and excessive consumption may produce laxative effects. A food supplement is not a substitute for a varied and balanced diet and a healthy lifestyle.

If your problem is frequent nightmares and broken nights, this is not the right tool. Not because the product is bad, but because that is not what there is evidence for.

The signs that mean speaking to a doctor or pharmacist

Here is the split that matters. On the ordinary side: an occasional nightmare, a bad night after a hard week, a frightening film that still got to you. On the other side, what deserves a conversation:

• Regular nightmares that are affecting your sleep and your daily life.
• Waking many times because of a disturbing dream.
• Dreams that leave you with intense fear, anger, sadness or disgust.
• Remembering the details and finding it hard to get back to sleep.
• Nightmares that began after a traumatic event.
• Physically acting out your dreams while asleep.

That last point deserves emphasis, because it is different from everything else. Acting out vivid dreams physically during sleep is not an ordinary nightmare: it is another sleep disorder and it needs medical attention. It is not resolved with routines.

For frequent nightmares that affect your life, there are psychological therapies, such as cognitive behavioural therapy, that may help. If the nightmares stem from a traumatic event, your doctor may recommend psychological treatment, such as counselling. That is a matter for a professional, not for a shelf.

How long before you know whether it is working

Do not expect change in two nights. Nightmares are irregular by nature, which makes it hard to judge an adjustment after a few days — a good week may be luck, not result. Give the set of changes you have chosen a stretch of several weeks, with the sleep diary alongside. Only then can you tell a real improvement from normal variation.

If, after that time, the nightmares are still cutting into your nights and unsettling your days, the next step is not another supplement or another search. It is booking an appointment. Most nightmares settle on their own, but the minority that do not have their own treatment, and that treatment is not found on a shop shelf.