Diagnosis & treatment

What causes insomnia? A look at insomnia symptoms and causes

What causes insomnia, and what are the main symptoms of insomnia? Now that we’ve taken some time to define insomnia and explore its effects, let’s turn our attention to identifying specific insomnia symptoms and causes.

Insomnia symptoms

Symptoms of insomnia range from simple sleeplessness to more complex health issues. Lying awake in bed before you’re able to sleep, an inability to sleep for more than a short period, waking up too early – these are all basic insomnia symptoms, according to the National Heart, Lung, and Blood Institute (NHLBI).1

The Mayo Clinic also lists Irritability, difficulty concentrating, a tendency toward increased errors or accidents and tension headaches as insomnia symptoms,2 while the National Sleep Foundation adds depression, stress and anxiety, stating that “people with insomnia are four times as likely to suffer from depression as people who sleep well.”3

However, when considering some of these symptoms of insomnia, it’s important to remember that insomnia itself is “both a symptom and a disorder.”4 For instance, insomnia may be considered a symptom of depression, rather than vice versa; as a 1999 study published in the Journal of Clinical Psychiatry pointed out, insomnia is reported as a symptom by more than 90 percent of patients with depression.5

For this reason, medical experts break insomnia down into two separate types: primary and secondary. “Secondary insomnia is the symptom or side effect of another problem,” according to the NHLBI. “Primary insomnia isn’t a symptom or side effect of another medical condition. It is its own distinct disorder, and its cause isn’t well understood.”6

Insomnia causes

This classification of insomnia into primary and secondary types is an important step to take before trying to figure out what causes insomnia. The cause of secondary insomnia is presumed to be the underlying health condition to which it’s connected – a list that commonly includes depression, arthritis, asthma, headache disorders, gastrointestinal disorders and stroke.6

However, primary insomnia causes are a bit harder to pin down. Because insomnia affects so many different types of people, and occurs in such a large segment of the population, it can be tough to find specific causes. The factors that cause insomnia will vary depending on your unique body type, age, lifestyle and other factors.

The NHLBI suggests that life changes may serve as a primary insomnia cause. “It may be due to major or long-lasting stress or emotional upset. Travel or other factors, such as work schedules that disrupt your sleep routine, also may trigger primary insomnia.”6

Medline Plus, an online publication of the U.S. National Library of Medicine, attempts to define the causes of primary insomnia by reasoning that sleep habits “learned as children may affect our sleep behaviors as adults” – particularly when those habits are repeated over many years to the point of becoming ingrained habits.7

The Mayo Clinic also notes that, while they may not be insomnia causes in and of themselves, certain factors increase your chances of having insomnia:2

  • Age. “Insomnia increases with age.”
  • Gender. “Women are much more likely to experience insomnia.”
  • Stress. “Stressful events can cause temporary insomnia.”
  • Mental health. “Early-morning awakening is a classic symptom of depression.”
  • Frequent travel. “Jet lag from traveling across multiple time zones can cause insomnia.”

Here are some other common insomnia causes according to Medline Plus and the Mayo Clinic:2,7

  • Lack of exercise
  • Worrying too much
  • Excessive napping during the day
  • Poor sleep environment (i.e., too bright or too noisy)
  • Working during the night or evening
  • Not having a consistent nightly bedtime
  • Spending time in bed while awake (i.e., reading or watching TV in bed)
  • The use of alcohol or tobacco
  • Using too much caffeine, “especially late in the day”
  • The overuse of “certain types of sleep medications,” cold medications and diet pills

We conclude by pointing out that sleep apnea – the focus of the blog – is also both a common cause and symptom of insomnia. If you’re experiencing issues similar to what’s been described here, talk to your doctor and ask whether you should take a sleep test.



  1. National Heart, Lung, and Blood Institute (NHLBI). “Insomnia.” Published/updated April 10, 2014 on Medline Plus. Retrieved from http://www.nlm.nih.gov/medlineplus/insomnia.html (accessed April 25, 2014).
  2. Mayo Clinic Staff. “Diseases and Conditions: Insomnia.” Published April 4, 2014 on the Mayo Clinic website. Retrieved from http://www.mayoclinic.org/diseases-conditions/insomnia/basics/definition/CON-20024293?p=1 (accessed April 25, 2014).
  3. The National Sleep Foundation. “Sleep Aids and Insomnia.” Retrieved from http://sleepfoundation.org/sleep-disorders-problems/insomnia/sleep-aids-and-insomnia (accessed April 24, 2014).
  4. Buysse DJ. “Chronic Insomnia.” Am J Psychiatry. Jun 2008; 165(6): 678–686. Retrieved from http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2859710/ (accessed April 25, 2014).
  5. Thase ME. “Antidepressant treatment of the depressed patient with insomnia.” J Clin Psychiatry. 1999;60 Suppl 17:28-31; discussion 46-8. Retrieved from http://www.ncbi.nlm.nih.gov/pubmed/10446739 (accessed April 25, 2014).
  6. National Heart, Lung, and Blood Institute (NHLBI). “What Causes Insomnia?” Published December 13, 2011. Retrieved from http://www.nhlbi.nih.gov/health/health-topics/topics/inso/causes.html (accessed April 24, 2014).
  7. U.S. National Library of Medicine. “Insomnia.” Published/updated August 16, 2011 on Medline Plus. Retrieved from http://www.nlm.nih.gov/medlineplus/ency/article/000805.htm (accessed April 24, 2014).


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