Shift workers are more likely to suffer from depression or other mental health disorders. Because of their disrupted daily cycle of the body, also known as the circadian rhythm.
Sarah DeWeerdt wrote an article about how disrupted sleep and unnatural exposure to light can increase the risk of depression. In 2018, researchers invited 23 people to a study on circadian rhythm. They wanted to understand why workers on night shifts have an approximately 25% to 40% higher risk of mental illness.
The findings suggested that one of the reasons for an increased risk of depression is the misalignment of the body's internal clock with the outside world. There is also growing evidence that circadian rhythm disturbances and altered light exposure (more artificial light at night and less natural daylight during the day) increase the risk of depression. According to one study, more than 90% of people with depression have sleep problems. So the two seem to be related. Sleep has a protective effect: better sleep can help prevent depression in adults. Previous studies have shown that light also has a direct antidepressant effect, by stimulating the mood-regulating brain centres. Cajochen even says that light is "as powerful as antidepressants".
Perhaps modern lifestyles need a little adjustment to improve circadian rhythms. For shift workers, the solution might be typical meal times or redesigning evening lighting in homes or night shift lighting in factories.