If the recent switch from daylight saving time to standard time makes you blue, you’re not alone. According to a recent study published in the journal Epidemiology, our routine of turning the clocks back in the fall may be significantly increasing our risk of seasonal depression, The Washington Post reports.

Seasonal depression, also known as seasonal affective disorder, or SAD, affects nearly 5 percent of the American population. The condition can be triggered by a transition from any season to another, not just from fall to winter. But this study is the first of its kind to prove a definitive link between the end of daylight saving time in the autumn and a significant increase in mental illness diagnoses.

For the study, researchers at Stanford and Aarhus universities examined a database of more than 185,000 people diagnosed with depression in Denmark between 1995 and 2012. By comparing the rates of depression diagnoses before and after time changes in the spring and fall, researchers discovered that the transition to standard time in November was associated with an 11 percent increase in episodes of depression. Interestingly, researchers did not find any corresponding decrease in depression diagnoses in April after the switch back to daylight saving time.

Although the findings don’t explain why a time shift in the fall might make people depressed, scientists theorized that the results probably involved the loss of one hour of daylight in the evening. In support of this theory, the study cited previous research demonstrating that long days and plenty of sunshine might be protective against symptoms of depression. In addition, researchers said that for individuals who previously experienced seasonal depression in the winter, the time change could act as an omen of upcoming depression, which could trigger a bout of the blues.

“In order to prevent depression following the transition from daylight saving time to standard time, we urge people to spend time outdoors when the sun is up,” said Søren D. Østergaard, MD, PhD, an associate professor at Aarhus University’s Department of Clinical Medicine and one of the study’s authors. And if that doesn’t help, scientists urged people to call their doctors to get appropriate treatment for their depression.

Click here to learn more about the effects of SAD and for tips on how to cope with the condition this winter.