The 11 Main Risk Factors of Insomnia (Research Backed)
Over time, researchers have found more and more risk factors of insomnia.
I’ve compiled a fairly comprehensive list of risk factors here, backed by scientific evidence.
These are roughly in order from highest risk to lowest, but it depends on which studies you’re looking at for some of the factors.
History of Poor Sleep (“Sleep Hygiene”)
A study of 464 people followed up twice over the course of the year to ask about their sleep quality and other factors like psychological and personality variables (1).
Of those, 30.7% developed insomnia symptoms (not full blown chronic insomnia), and 7.4% developed insomnia syndrome by the end of the 1 year period.
What they found was that the most important risk factor for chronic insomnia was a history of subjective poor sleep.
In other words, these subjects had “poor” or “light” sleep often in the past. Not bad enough to cause insomnia, but enough to notice. Then, some sort of stress or biological change tipped them over the edge and they developed clinical insomnia.
Typically, having poor sleep like this is associated with poor sleep hygiene:
- Exposure to blue light at night
- Naps during the day
- Infrequent sleep schedule (shift work)
- Poor diet
- Not relaxing before going to sleep
- Sleeping where it’s not dark enough
- Noisy environment
- Too hot (should be 17-23 degrees Celsius)
- Plane travel
- Exercising before sleep
These are all things you can fix if you’re willing to make a few habit changes and improvements to your sleep environment.
SummaryPeopls who have light or poor (restless) sleep are at high risk of developing insomnia in the future. It's good to address it before it becomes a big problem.
A study followed up with over 1,000 members of a sleep cohort after 7.5 years. They only looked at people who originally didn’t have insomnia, and analyzed why some people developed it (2).
The biggest finding was that:
The presence of mental health problems are stronger predictors of incident chronic insomnia compared to physical health problems.
Specifically, they found that poor mental health markers of depression or alcohol disorder were strong predictors of chronic insomnia.
This is arguably the hardest type of insomnia to correct because of the deep connection between insomnia and depression. Certain antidepressants help those with sleep trouble, while others can make issues worse.
SummaryIf you have a history of depression or alcohol abuse, there’s a good chance that you will develop insomnia symptoms or syndrome at some point in the future. It’s not easy to “fix” these, but try to proactively get help.
Stress and Anxiety
Stress and anxiety are related to mental health, but a bit different from a disorder like depression.
Everyone has some level of stress and anxiety, but some people have higher levels than others.
Research has shown that a higher tendency to experience anxiety is a strong risk factor for new onset insomnia syndrome (3).
Stress and anxiety from negative life events (e.g. trauma, grief, work troubles, etc.) are likely to cause acute (temporary) insomnia, which is likely to go away by itself in time.
See our guide to the different types of insomnia for more detail.
A common scenario is for stress to trigger other conditions, which then lead to further sleep issues. For example, research shows that stress can cause tinnitus, which can cause insomnia.
SummaryIf you’re frequently stressed, it could lead to insomnia symptoms or syndrome. Different relaxation techniques like massage, yoga, and meditation have been shown to be effective at reducing insomnia symptoms in people with anxiety issues.
Here’s the thing, weight gain is a common side effect of insomnia.
This especially sucks because obesity is a risk factor for insomnia. One study found that obese subjects were 38.5% more likely to develop insomnia (2).
It’s a very tough cycle to get out of once you're in it.
You need to make good decisions about food and exercise while exhausted, which not many people can do. That’s why insomnia caused by obesity is so hard to fix by yourself.
What’s considered obese?
In that study, obese was defined by a BMI of over 30.
Here’s a nice chart from BraceAbility to help you calculate yours:
BMI isn’t a perfect measure if you’re extremely fit, but otherwise it’s pretty accurate.
Note that overweight begins at a BMI of 25, and it doesn’t take much to slide into that obese category, so be careful if you fall into it.
Most conditions that can contribute to weight gain are correlated with sleep trouble. For example, here's a detailed look at how thyroid problems can cause insomnia.
SummaryBeing overweight can lead to developing insomnia. Losing weight is easier to fix before sleep issues set in.
There’s some conflicting data out there about age and insomnia.
Some studies suggest that people over 60 are more likely to have insomnia because they’re more at risk of bodily changes related to aging (like less bladder control, and taking medication).
However, the most comprehensive study I’ve seen that included age found that people 20-35 had the highest risk of insomnia (2).
The explanation from the researchers is that:
The younger subjects may be at increased risk for experiencing significant life stressors (i.e., marriage, birth of children), vulnerability to stress, and physiological sleep changes than older subjects.
Additionally, their study didn’t include people who already had insomnia to begin with, so it’s possible that the only older people who were left to look at were really good sleepers to begin with.
SummaryResearch shows that both young adults (20-35 years old), and senior adults (60+) are at the highest risk of developing insomnia symptoms. As the issues for young adults are mostly related to stress, it’s more likely to be a temporary case of insomnia.
Insomnia in pregnant women is incredibly common.
There are 3 main causes of insomnia for pregnant women:
Having a child comes with a lot of stress, and depression around labor is common. However, we looked at those risk factors already.
The other risk factor is more interesting now - hormonal changes.
Levels of estrogen and progesterone go up, and these in turn affect other hormones like cortisol and melatonin that affect sleep (and not in a good way).
SummaryHormonal changes during pregnancy are one of the few insomnia risk factors that can’t be treated. If you are pregnant, try to manage the other risk factors the best you can to minimize the severity and risk of any insomnia symptoms.
Drinking Too Much Caffeine (Coffee)
Before you panic, some caffeine is fine.
One of the studies I mentioned before found that (2):
Individuals who consumed on average >3 cups of coffee had the highest incidence of chronic insomnia.
However, people who had 1-2 cups of coffee per day had the lowest risk of incident insomnia.
If you drank none, your relative risk is still low, but slightly higher. While not conclusive, the researchers hypothesized that this is because people who are sensitive to caffeine (who would suffer on 1-2 cups of coffee per day) would already know that and avoid it.
In reality, with perfect data, it’s likely that having 0-2 cups of coffee per day carries about the same risk.
See our overview of how caffeine can cause insomnia for more detail.
SummaryIf you’re a heavy caffeine drinker, you’re much more likely to develop insomnia. In general, scaling back on drinking coffee or switching to decaf can help reduce sleep issues.
Alcohol and Drug Use
In that same study mentioned just above, the researchers found a similar trend in alcohol use (2).
Having 3 or more alcoholic drinks per day resulted in the highest risk of insomnia.
But have 2 or fewer and you’re basically good to go.
Secondly, abusing drugs is known to cause insomnia, but it’s hard to study this in detail for obvious reasons (“we just want to give everyone a bit of heroin for our experiment, how could that possibly go wrong?”).
If alcohol use is stopped, insomnia doesn't necessarily go away right away. Most research shows that insomnia after quitting drinking usually lasts 3-6 months.
SummaryIf you consume a large amount of alcohol or drugs on a regular basis, you are putting yourself at a higher risk of developing insomnia. Seek help if you think you may have a problem.
Comorbidity (Other Physical Health Conditions)
This is a complex and detailed topic, so I’m only going to skim the surface here.
Basically, there are 2 ways that having other health issues can cause insomnia.
First is from the treatment of a condition. For example, the treatment for many types of cancer is known to cause insomnia (4). Alternatively, many types of medication like antidepressants can make insomnia worse.
The second way is that the disease causes insomnia symptoms directly. Some of those include:
- Kidney disease
- Lung disease
- Alzheimer disease
- Parkinson disease
- Heart disease
- Sinus infections
- Gastrointestinal reflux disease (GERD)
- Restless legs syndrome
- Acid reflux
Unfortunately, treating the underlying condition is always a priority, and there’s not much you can do about insomnia.
SummaryIf you have a family history that puts you at high risk of a condition associated with insomnia (e.g. heart disease), do whatever you can to lower that risk if you have not already.
Here’s another risk factor that’s a bit fuzzy in research.
Most studies have found that women have a much higher risk of insomnia than men.
Here’s an example of one such finding (2):
Incidence of chronic insomnia was 9.3%, with a higher incidence in women (12.9%) than in men (6.2%).
On one hand, hormonal changes (PMS) and pregnancy are known to cause insomnia. Women also do tend to react more emotionally to stressful events in their lives.
However, men are more likely to abuse alcohol and drugs to cope with stress.
Finally, women are more likely to report insomnia symptoms and other health issues because many men feel like needing help is “weak.” In turn, women are typically over reported for certain health conditions in research.
SummaryResearch suggests that women are more likely to develop insomnia, mainly due to hormonal issues outside of their control. There’s nothing you can do about this risk factor other than be aware of it.
Many people say that sleep apnea is a risk factor of insomnia, so I wanted to address it here.
The latest data is showing that sleep apnea is probably not a factor, or a very minor one at most.
Here’s a relevant quote from one of the studies I’ve mentioned multiple times in this post (2):
Consistent with our previous cross-sectional study, sleep apnea was not significantly associated with incident chronic insomnia in the present study.
So if you have sleep apnea, by all means you should try to fix it, but it’s probably not contributing much to any insomnia symptoms you might have.
- Incidence and risk factors of insomnia in a population-based sample
- Risk Factors for Incident Chronic Insomnia: A General Population Prospective Study
- Incidence and Risk Factors of Insomnia in a Population-Based Sample
- Prostate cancer treatments and their side effects are associated with increased insomnia
Medical Disclaimer: The information on SnoozeUniversity.com is not intended to be a substitute for physician or other qualified care. We simply aim to inform people struggling with sleep issues about the nature of their condition and/or prescribed treatment.