Can Working Night Shifts Cause Insomnia?

Shift work puts people at a greater risk of developing circadian rhythm sleep disorder (also called shift work disorder).

It’s a condition recognized in the International Classification of Sleep Disorders, and its main symptom is insomnia and excessive sleepiness.

We’re going to go over the research behind shift work and sleep issues shortly, but know that the main cause is the disruption of the circadian rhythm (which controls when and how we sleep).

By not getting normal exposure to sunlight, the circadian rhythm can be thrown off and cause all sorts of sleep issues.

Let’s look at this in more detail, and how insomnia in night shift workers can be treated.

How Common is Insomnia For Shift Workers?

If we put together a variety of studies, we can see that shift work disorder occurs in roughly:

• 32-37% of night shift workers (1)
• 8-26% of rotating shift workers (1, 2)
• 10% of day workers (3)

In other words, the more night shifts someone works, the more likely it is for them to develop insomnia as a result of circadian rhythm sleep disorders.

Rotating shifts (between periods of night and day work) are slightly better, but some people adapt to them better than others.

Does Insomnia Severity Differ for Night or Day Shift Work?

One other relevant question is whether or not night shift workers suffer the same severity of sleep troubles in most cases.

One study looked at this topic in great detail, with a sample of 418 adults of all types of work (4). They found:

• Insomnia symptoms in both night and rotating shift workers had a similar profile to that of insomnia in day workers.
• Overall sleep time was related to the degree of insomnia, but not the type of shift work.
• Night workers with insomnia reported higher scores in overall pain and lower scores in social life.

So while some of the consequences of sleeplessness might be worse for night shift work, there’s nothing too different from “normal” insomnia cases.

Consequences of Night Shift Insomnia

If someone works shifts and night for years and develops shift work sleep disorder, research shows that those sleep issues are likely to continue even after shift work stops (5).

Most insomnia symptoms in night shift employees are the same as the regular side effects of insomnia (6):

• Anxiety
• Depression
• Fatigue

In addition, one study showed that constant night shifts are the worst for health (7):

Among all shift types, workers with fixed night shifts were found to have the shortest duration of sleep, highest level of burnout score, and highest prevalence of insomnia and minor mental disorders.

Burning out is a particularly interesting symptom, as it means that insomnia in this case doesn’t negatively affect just mental and physical health, but also career (financial) health.

Treatment for Shift Work Insomnia

The typical treatment prescribed for insomnia by doctors is cognitive behavioral therapy (CBT-i) and sometimes sleep medication.

While both of those might help a bit, they will not fix circadian rhythm sleep disorder because they don’t treat the underlying issue (lack of proper light exposure leading to shift work disorder).

Recent research has shown promising results from using bright light therapy for insomnia.

One study exposed night shift patients to bright light during the first half of their shift, and then gradually reduced it throughout the morning, with good outcomes (8):

The Insomnia Severity Index (ISI), Hospital Anxiety Depression Scale (HADS), and subscales of the HADS scores were significantly improved in the treatment group as compared with the control group.

A simple graph makes the results really clear:

On top of light therapy, good sleep hygiene is also crucial.

During the day, there’s typically more light and noise pollution that can disrupt sleep, which means that sleep aids like blackout curtains, ear plugs, and white noise machines are even more important in many cases.

What About Sleep Medicine for Shift Work?

Sleep medication is also an option for shift workers with insomnia symptoms having trouble falling asleep or staying asleep.

A 2021 study of Finnish public sector employees found that night shift workers were 1.28-1.33 times more likely to be prescribed sleep medication (9). Other shift workers (not just nights) also have an increased rate.

Obviously physicians felt that their patients met insomnia criteria and medication was necessary.

However, sleep medication has significant potential drawbacks:

• There are often side effects (most commonly mood changes or excessive sleepiness at the wrong times)
• You can develop a tolerance and also experience withdrawal symptoms to some
• The effectiveness of sleep medicine varies among people, so it can take significant testing to find one that has a positive effect.

This is why non-pharmacological treatment like CBT is typically preferred for insomnia.

At the same time, CBT can only go so far, and shift work by its very nature is not good for maintaining a healthy sleep schedule. So even though sleep medicine isn’t always preferred, it may be the best option for sleep quality in a bad situation.

Summary: Insomnia and Night or Rotating Shifts

Night and rotating shifts both put people at a great risk of developing insomnia as a symptom of circadian rhythm sleep disorder.

Approximately 1 in 3 night shift workers develop shift work sleep disorder, and it can lead to long term issues with sleep.

For now, research suggests that adding light therapy to a traditional insomnia treatment plan (created and supervised by a medical professional) is the most effective way to address this disorder.

In addition, it's important to rule out other common sleep problems like sleep apnea that may exacerbate poor sleep quality.

References

1. Shift Work Disorder in Nurses – Assessment, Prevalence and Related Health Problems
2. Shift Work Disorder in a Random Population Sample
3. Shift Work Sleep Disorder: Prevalence and Consequences Beyond that of Symptomatic Day Workers
4. Insomnia in shift work
5. Sleep Quality of Former Night-shift Workers
6. Insomnia Induced by Night Shift Work is Associated with Anxiety, Depression, and Fatigue, among Critical Care Nurses
7. Night shift and rotating shift in association with sleep problems, burnout and minor mental disorder in male and female employees
8. The Effectiveness of Light/Dark Exposure to Treat Insomnia in Female Nurses Undertaking Shift Work during the Evening/Night Shift
9. Association of rotating shift work schedules and the use of prescribed sleep medication: A prospective cohort study