What Causes Insomnia? 12 Common Causes and Risk Factors
What Causes Insomnia? 12 Common Causes and Risk Factors
Insomnia can be frustrating, especially when you’re tired but your mind or body won’t settle down for sleep.
Sometimes the reason is easy to identify. A stressful week, a new work schedule, jet lag, too much caffeine or a noisy bedroom may be enough to disrupt your sleep.
Other times, insomnia is more complicated. Anxiety, depression, chronic pain, medications, hormonal changes, medical conditions or another sleep disorder may play a role.
And sometimes there isn’t one obvious cause at all.
Understanding what may be contributing to your insomnia can help you decide what to change, what to monitor and when it may be worth speaking with a healthcare professional.
What Causes Insomnia?
Insomnia can have many possible causes.
Some are temporary, such as stress or travel. Others can continue for months or contribute to a longer-term pattern.
Common contributors include:
- Stress
- Anxiety and excessive worry
- Irregular sleep schedules
- Caffeine and nicotine
- Alcohol
- Poor sleep habits
- Excessive screen or nighttime stimulation
- Medical conditions and pain
- Medications
- Other sleep disorders
- Age and hormonal changes
- Family history and individual risk factors
Let’s look at each one.
1. Stress
Stress is one of the most common reasons sleep becomes difficult.
Your brain doesn’t necessarily stop thinking just because you turn off the lights.
You may lie in bed thinking about:
- Work
- Money
- Family
- Relationships
- School
- Health concerns
- Deadlines
- Tomorrow’s responsibilities
A stressful event can trigger short-term sleep problems. Long-lasting stress can contribute to a more persistent pattern.
NHLBI lists stress and worrying about work, school, relationships, money or major life events as factors that can increase the risk of insomnia.
Stress can also create a sleep cycle
You have a stressful day.
↓
You sleep poorly.
↓
You worry about being tired tomorrow.
↓
You become more focused on whether you’ll sleep.
↓
Bedtime becomes stressful.
↓
Falling asleep becomes harder.
This is one reason persistent insomnia can sometimes continue even after the original stressful event has passed.
Related article: [How Stress Affects Your Sleep]
2. Anxiety and Racing Thoughts
Stress and anxiety are closely related, but they aren’t exactly the same.
Anxiety can make your mind feel continuously alert.
When you’re trying to sleep, you might find yourself:
- Replaying conversations
- Thinking about future problems
- Imagining things going wrong
- Checking the time repeatedly
- Worrying about not getting enough sleep
- Planning tomorrow in your head
Mayo Clinic notes that anxiety and other mental health conditions can contribute to insomnia.
This can be particularly frustrating because you may feel physically exhausted while your mind feels completely awake.
Related article: [Can Anxiety Cause Insomnia? Understanding the Connection]
3. An Irregular Sleep Schedule
Your body has an internal timing system that helps coordinate when you’re awake and when you’re sleepy.
Frequently changing your sleep schedule can interfere with this rhythm.
Examples include:
- Working night shifts
- Rotating shifts
- Going to bed at very different times
- Sleeping very late on weekends
- Traveling across time zones
- Frequently changing work schedules
NHLBI identifies shift work, travel across time zones and schedule changes as factors that can disturb the sleep-wake cycle.
For example:
Monday: Bed at 10:30 PM
Tuesday: Bed at 1:00 AM
Wednesday: Bed at 11:30 PM
Thursday: Bed at 2:00 AM
Your body may have difficulty establishing a predictable sleep pattern.
Related article: [How to Fix Your Sleep Schedule]
4. Too Much Caffeine
Caffeine is a stimulant.
For some people, drinking coffee late in the day can make falling asleep more difficult.
And coffee isn’t the only source.
Caffeine can also be found in:
- Tea
- Energy drinks
- Cola
- Chocolate
- Some medications
- Certain supplements
NHLBI specifically lists caffeine among lifestyle factors that can increase insomnia risk.
If you’re having trouble sleeping, consider looking at when you’re consuming caffeine rather than only how much.
Some people are more sensitive to caffeine than others.
Related article: [How Caffeine Affects Sleep and How Late Is Too Late for Coffee?]
5. Nicotine
Nicotine is also a stimulant and can affect sleep.
People who use nicotine may experience difficulty falling asleep or changes in sleep patterns.
NHLBI recommends avoiding nicotine close to bedtime because it can make falling asleep more difficult.
If you use nicotine and regularly experience sleep problems, discuss your options for reducing or quitting with an appropriate healthcare professional.
6. Alcohol
Alcohol can make some people feel sleepy at first.
That can create the impression that it helps with insomnia.
But feeling sleepy isn’t the same as getting consistently restorative sleep.
Alcohol can alter sleep and contribute to waking during the night. Mayo Clinic identifies alcohol among substances that can interfere with sleep.
If you regularly use alcohol as a way to fall asleep, it’s worth discussing the pattern with a healthcare professional rather than relying on it as a sleep strategy.
7. Poor Sleep Habits
Your daily routine can have a significant effect on your sleep.
Examples of habits that may contribute to insomnia include:
- Going to bed at inconsistent times
- Waking at inconsistent times
- Taking long daytime naps
- Being inactive during the day
- Exercising too close to bedtime if it makes you more alert
- Working from bed
- Watching television in bed
- Eating large meals late at night
- Spending long periods awake in bed
NHLBI and Mayo Clinic both identify inconsistent schedules, naps, stimulating activities and other sleep-habit factors as contributors to insomnia.
One important distinction
Good sleep habits can help, but sleep hygiene isn’t always enough to treat chronic insomnia.
For persistent insomnia, evidence-based treatments such as cognitive behavioral therapy for insomnia (CBT-I) may be more appropriate. The American Academy of Sleep Medicine recommends behavioral and psychological treatments for chronic insomnia, with CBT-I among the recommended approaches.
8. Phones, Computers and Nighttime Stimulation
Your phone may not be the entire reason you can’t sleep.
The bigger issue may be what you’re doing on it.
For example:
- Checking work emails
- Watching intense videos
- Playing games
- Reading upsetting news
- Arguing on social media
- Constantly checking messages
These activities can keep your brain engaged when you’re trying to wind down.
Mayo Clinic includes computer, smartphone, television and other stimulating activities close to bedtime among habits that can disrupt sleep.
Try creating a short period before bed where you move away from work and highly stimulating activities.
9. Your Sleeping Environment
Sometimes the cause is closer to home—or more specifically, closer to your bed.
Your bedroom may be:
- Too bright
- Too noisy
- Too hot
- Too cold
- Uncomfortable
- Disrupted by pets
- Associated with work or entertainment
NHLBI identifies environmental factors such as noise, light and uncomfortable temperatures as potential contributors to insomnia.
A bedroom that is dark, quiet and comfortable can make it easier to establish a consistent sleep routine.
10. Medical Conditions and Chronic Pain
Insomnia can sometimes occur because another health condition is making sleep difficult.
Examples include:
- Chronic pain
- Arthritis
- Asthma
- Gastroesophageal reflux disease (GERD)
- Diabetes
- Heart disease
- Certain neurological conditions
- Thyroid problems
Mayo Clinic lists several medical conditions that can be associated with insomnia, including ongoing pain, asthma, GERD, diabetes, heart disease and certain neurological conditions.
For example, someone with chronic back pain may be physically tired but repeatedly wake because of discomfort.
In this situation, simply trying to improve sleep habits may not address the underlying problem.
Treating the health condition may be an important part of improving sleep.
11. Medications
Some medications can interfere with sleep.
Examples can include certain medicines used for:
- Depression
- Asthma
- Blood pressure
- Pain
- Allergies
- Colds
Some over-the-counter products may also contain caffeine or other stimulants.
Mayo Clinic notes that both prescription and over-the-counter medicines can sometimes contribute to insomnia.
Don’t stop medication on your own
If you suspect a medication is affecting your sleep, speak with your doctor or pharmacist.
They can determine whether the medication, dosage or timing could be contributing.
Never stop a prescribed medication simply because you read online that it may affect sleep.
12. Another Sleep Disorder
Sometimes what looks like insomnia may be connected to another sleep disorder.
Two examples are sleep apnea and restless legs syndrome.
Sleep apnea
Sleep apnea can cause repeated interruptions in breathing during sleep.
Possible warning signs include:
- Loud snoring
- Gasping during sleep
- Witnessed pauses in breathing
- Morning headaches
- Excessive daytime sleepiness
If you experience these symptoms, speak with a healthcare professional.
Restless legs syndrome
Restless legs syndrome can cause an uncomfortable urge to move the legs, particularly when resting.
That sensation can make it difficult to fall asleep or return to sleep.
Mayo Clinic identifies sleep apnea and restless legs syndrome among sleep-related conditions that can interfere with sleep.
Other Factors That May Increase the Risk of Insomnia
The causes above are not the only factors worth considering.
Age
Insomnia can occur at any age, but it becomes more common as people get older.
Changes in sleep patterns, health conditions, medications and activity levels can all contribute.
Family history
NHLBI notes that insomnia can sometimes run in families and that genetics may influence sleep characteristics.
Having a family member with insomnia doesn’t mean you will develop it, but it may be one factor among several.
Hormonal changes
Hormonal changes can affect sleep.
For some women, menstrual-cycle changes, pregnancy or menopause can be associated with sleep difficulties. Night sweats and hot flashes during menopause may also interrupt sleep.
Mental health conditions
Depression, anxiety and other mental health conditions can occur alongside insomnia.
The relationship can work in both directions: mental health problems can disrupt sleep, while persistent sleep problems can also affect emotional wellbeing.
If sleep difficulties occur alongside significant changes in mood or anxiety, consider discussing both with a healthcare professional.
Why Can’t You Always Find One Cause?
This is one of the most important things to understand about insomnia.
You might have several contributing factors at the same time.
For example:
Stress
Late caffeine
Irregular bedtime
Worrying about sleep
=
A much harder night of sleep
Removing one factor may help, but it may not completely solve the problem if other factors remain.
This is why persistent insomnia sometimes requires a broader evaluation.
The Sleep Problem Can Become the Problem
Imagine that you have one stressful week and sleep badly for several nights.
You start worrying:
“What if I can’t sleep tonight?”
You go to bed earlier than usual because you’re exhausted.
Then you spend two hours awake in bed.
You check the clock repeatedly.
You become frustrated.
The next morning, you’re exhausted.
By the evening, you’re already worried about the upcoming night.
Over time, the original stress may disappear, but the fear and frustration surrounding sleep can remain.
This is one of the patterns that behavioral treatments such as CBT-I are designed to address.
How Can You Figure Out What Is Causing Your Insomnia?
You don’t necessarily need to guess.
Start by looking for patterns.
Keep a sleep diary
For one to two weeks, record:
- When you went to bed
- Approximately when you fell asleep
- When you woke during the night
- When you finally got up
- Whether you napped
- Caffeine intake
- Alcohol intake
- Exercise
- Stressful events
- How rested you felt the next day
NHLBI recommends keeping a sleep diary for around one to two weeks when evaluating insomnia.
Example
| Day | Bedtime | Estimated sleep time | Wake time | Caffeine | Nap | Notes |
|---|---|---|---|---|---|---|
| Monday | 11 PM | 12 AM | 7 AM | 2 coffees | No | Work stress |
| Tuesday | 11:30 PM | 1 AM | 7 AM | 3 coffees | Yes | Late nap |
| Wednesday | 10:30 PM | 11 PM | 6:45 AM | 1 coffee | No | Better night |
Patterns can sometimes become much easier to see when they’re written down.
What Can You Do If You Think You Know the Cause?
The answer depends on the cause.
If stress seems to be the problem
Work on reducing nighttime stimulation and consider relaxation techniques or professional support if stress is persistent.
If caffeine seems to be the problem
Experiment with moving caffeine earlier in the day.
If your schedule is inconsistent
Try establishing a consistent wake-up time.
If your phone keeps you awake
Create a screen-free wind-down period before bed.
If pain is waking you
Discuss the pain with a healthcare professional rather than treating only the sleep problem.
If medication may be involved
Talk to your doctor or pharmacist.
If you snore or wake gasping
Ask a healthcare professional whether you should be evaluated for sleep apnea.
If insomnia continues
Consider professional evaluation and ask about evidence-based insomnia treatments such as CBT-I.
When Should You Talk to a Healthcare Professional?
Occasional difficulty sleeping is common.
But consider getting professional advice if:
- Sleep problems happen repeatedly.
- You’re regularly exhausted during the day.
- Insomnia affects work, school or daily activities.
- You have difficulty concentrating.
- You’re regularly waking much earlier than intended.
- You frequently wake throughout the night.
- You snore loudly or wake gasping.
- You have persistent pain.
- You think medication is affecting your sleep.
- Anxiety or low mood is affecting your sleep.
- Your sleep problems have continued for months.
Mayo Clinic recommends seeking medical attention when insomnia makes daily activities difficult.
If excessive sleepiness is affecting your ability to drive safely or perform other safety-sensitive activities, take appropriate precautions and seek medical advice.
Can You Prevent Insomnia?
You can’t prevent every case of insomnia.
Some factors—such as age, genetics or unexpected life events—aren’t completely under your control.
But healthy sleep habits can reduce some avoidable contributors.
Helpful habits may include:
- Keeping a consistent sleep schedule
- Getting regular daytime activity
- Limiting long naps
- Avoiding caffeine close to bedtime
- Avoiding nicotine close to bedtime
- Limiting alcohol as a sleep strategy
- Creating a comfortable bedroom
- Developing a relaxing bedtime routine
- Avoiding large meals immediately before bed
NHLBI and Mayo Clinic both recommend regular schedules and healthy sleep habits as part of preventing or managing insomnia.
Frequently Asked Questions
What is the most common cause of insomnia?
There isn’t one cause that applies to everyone.
Stress, anxiety, irregular schedules, lifestyle habits, medical conditions, medications and other sleep disorders can all contribute.
Can stress cause insomnia?
Yes. Stress can make it difficult to relax and can contribute to both short-term and longer-lasting sleep problems.
Can anxiety cause insomnia?
Yes. Anxiety and excessive worry can interfere with the transition from wakefulness to sleep and may occur alongside insomnia.
Can caffeine cause insomnia?
Yes. Caffeine is a stimulant and can make it harder to fall asleep, particularly when consumed later in the day.
Can alcohol cause insomnia?
Alcohol can make some people feel sleepy initially, but it can interfere with sleep later in the night.
Can your phone cause insomnia?
Phone use isn’t necessarily the only cause of insomnia, but stimulating activities and screen use close to bedtime can interfere with winding down and sleep routines.
Can medications cause insomnia?
Yes. Some prescription and over-the-counter medications can interfere with sleep. If you suspect a medication is contributing, speak with your doctor or pharmacist rather than stopping it yourself.
Can a medical condition cause insomnia?
Yes. Chronic pain, reflux, asthma, certain neurological conditions and other health problems can contribute to sleep difficulties.
Can insomnia be caused by another sleep disorder?
Yes. Conditions such as sleep apnea and restless legs syndrome can interfere with sleep and may need separate evaluation.
When does insomnia become chronic?
Chronic insomnia is generally characterized by symptoms occurring at least three nights per week for three months or longer, with associated daytime effects.
The Bottom Line
Insomnia rarely has one universal cause.
For one person, stress may be the main trigger. For another, an irregular work schedule, caffeine, anxiety, chronic pain, medication or another sleep disorder may be involved.
Sometimes several factors work together.
The most useful question isn’t simply:
“Why can’t I sleep?”
It is:
“What has changed, what patterns do I notice, and what might be interfering with my sleep?”
If sleep problems continue, keeping a sleep diary and discussing your symptoms with a healthcare professional can help identify possible causes.
And if you’re dealing with persistent insomnia, remember that you don’t have to simply accept sleepless nights. Evidence-based treatments such as CBT-I are available for chronic insomnia.
Sources & Further Reading
- National Heart, Lung, and Blood Institute (NIH) — Insomnia: Causes and Risk Factors
- National Heart, Lung, and Blood Institute (NIH) — Insomnia: Diagnosis
- Mayo Clinic — Insomnia: Symptoms and Causes
- Mayo Clinic — Insomnia: Treatment
- American Academy of Sleep Medicine — Behavioral and Psychological Treatments for Chronic Insomnia
Medical Disclaimer
This article is provided for general educational and informational purposes only. It is not a substitute for professional medical advice, diagnosis or treatment. If you have persistent, severe or concerning sleep problems, speak with a qualified healthcare professional.