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Insomnia is usually caused by a combination of stress, health problems, medicines or substances, disrupted sleep habits, and changes to the body's sleep-wake rhythm. It can make it hard to fall asleep, stay asleep, or avoid waking too early despite having enough time and opportunity to sleep. Chronic insomnia occurs at least 3 nights per week for 3 months or longer and affects daytime functioning.
Common Causes of Insomnia at a Glance
| Cause | Examples |
|---|---|
| Stress and emotional distress | Work pressure, financial worries, grief, anxiety, depression and relationship problems |
| Medical conditions | Chronic pain, acid reflux, asthma, thyroid disorders, pregnancy and menopause |
| Other sleep disorders | Sleep apnea, restless legs syndrome and circadian rhythm sleep-wake disorders |
| Medicines and substances | Caffeine, nicotine, alcohol, some cold medicines, diet pills and prescription medicines |
| Sleep habits and environment | Irregular bedtimes, long naps, screens before bed, noise, light and uncomfortable temperatures |
| Schedule changes | Shift work, jet lag and travel across time zones |
| Age and genetics | Age-related sleep changes and a family tendency toward insomnia |
How Do Stress and Anxiety Cause Insomnia?
Stress and anxiety can keep the brain alert when it should be preparing for sleep. Worries about work, money, health, relationships or a traumatic event may lead to short-term insomnia lasting days or weeks.
Insomnia can then reinforce itself. After several poor nights, you may start watching the clock, worrying about sleep or spending long periods awake in bed. That anxiety can make it harder to fall asleep the following night.
Anxiety, depression, emotional distress and bipolar disorder are also associated with sleep problems. In some cases, insomnia appears before a person recognizes another mental health condition.
Which Medical Conditions Can Cause Insomnia?
Several medical conditions can cause insomnia by producing pain, breathing problems, reflux, hormonal changes or the need to urinate during the night. They include:
- Chronic muscle, joint or nerve pain
- Acid reflux
- Asthma and other breathing problems
- Thyroid disorders
- Enlarged prostate and nighttime urination
- Pregnancy
- Menopause
- Parkinson's disease and other neurological conditions
Treating the underlying condition may improve sleep. Persistent insomnia may still need separate treatment.
Can Another Sleep Disorder Look Like Insomnia?
Yes. Sleep apnea, restless legs syndrome and circadian rhythm sleep-wake disorders can cause symptoms that feel like insomnia.
- Sleep apnea can cause repeated awakenings, loud snoring, gasping or choking during sleep.
- Restless legs syndrome causes uncomfortable sensations and an urge to move the legs, especially in the evening.
- Circadian rhythm disorders make it difficult to sleep at socially expected times. Shift work, jet lag and a severely delayed sleep schedule can contribute.
You can have insomnia and another sleep disorder at the same time.
Which Medicines and Substances Can Interfere With Sleep?
Several medicines and substances can interfere with sleep, including:
- Caffeine, especially later in the day
- Nicotine
- Alcohol
- Recreational drugs
- Some cold medicines and decongestants
- Diet pills and stimulants
- Certain prescription medicines
- Some herbs and supplements
Alcohol may make you feel sleepy at first, but it can lead to poorer-quality sleep and more waking during the night. Do not stop or change a prescribed medicine without medical advice.
How Do Sleep Habits and the Environment Contribute?
Inconsistent sleep routines and an uncomfortable sleep environment can cause or worsen insomnia. Common factors include:
- Going to bed and waking up at different times
- Taking long or late daytime naps
- Spending long periods awake in bed
- Getting too little physical activity
- Using a phone, computer or television close to bedtime
- Exposure to noise or light during the night
- A bedroom that is too hot, cold or uncomfortable
- Waking frequently to care for a baby
Night-shift work, rotating schedules and frequent travel across time zones can also disrupt the circadian rhythm, the internal timing system that regulates sleep and wakefulness.
Do Age, Sex or Genetics Affect Insomnia Risk?
Yes. Age, sex, hormonal changes and genetics can affect the risk of insomnia.
Insomnia can occur at any age, but the risk increases with age. Older adults may sleep more lightly, wake more often and experience changes in their sleep schedule. Insomnia also sometimes runs in families, which suggests that genetics may influence sleep sensitivity and the tendency to be a light sleeper.
Pregnancy and menopause can make sleep more difficult because of hormonal changes. Insomnia is reported more often in women than in men.
What Is the Difference Between Short-Term and Chronic Insomnia?
Short-term insomnia often follows a clear trigger, such as stress, illness, pain, travel or a change in schedule. It may last for several days or weeks.
Chronic insomnia occurs at least 3 nights per week for 3 months or longer and affects daytime functioning. It may be linked to a health condition, medicine or substance. It can also continue after the original trigger has passed.
When Should You See a Healthcare Professional?
Speak with a healthcare professional if insomnia persists, affects work or daily activities, or leaves you excessively sleepy during the day. Seek an evaluation if you:
- Snore loudly or wake up gasping
- Have uncomfortable or restless legs at night
- Experience significant pain, reflux or breathing problems
- Have symptoms of depression, severe anxiety or unusually elevated mood
- Regularly rely on alcohol or sleep medicines to sleep
- Feel drowsy while driving
A clinician may review your health conditions and medicines, ask about your sleep schedule, recommend a sleep diary, or arrange testing for sleep apnea, circadian rhythm disorders or another cause.