Night owls are more prone to depression than early lark, suggesting there’s something about the timing of sleep that impacts mood. However, some people are naturally inclined to be night owls, particularly young adults.
Night owls can often have a delay in the timing of their circadian clock in the suprachiasmatic nucleus (SCN). This delay can make it more difficult for them to sleep and wake up at times when society wants them to, often trying to get up earlier for work or school. This mismatch between a night owl’s preferred timing and the timing they need or want to be on can lead to circadian misalignment. Over time, circadian misalignment has been linked to depression.
Chronotherapies are interventions that leverage the synchronizing properties of light to shift the timing of the circadian clock. For most people, light in the morning can shift the clock earlier, while light in the evening can delay it. Chronotherapies can successfully shift the circadian clock, but the evidence has been mixed about their effectiveness in treating depression. It is possible that chronotherapies are most effective for night owls with depression, whose depression may be more linked to their delayed sleep timing tendencies.
In a recent pilot study, we tested a chronotherapeutic intervention in young adults ages 18-25 who were night owls with depression. Our intervention, which included wearable bright light glasses in the morning, evening blue-light blocking glasses, and an individualized sleep schedule, successfully advanced the timing of sleep, the circadian clock, and improved depression. The fact that these improvements were linked with the timing shifts reassures us about the potential of chronotherapies for night owls.
Chronotherapeutic interventions are a non-invasive, effective treatment for depression, particularly for individuals who consider themselves night owls. Our research suggests combining morning light and decreasing evening light work together to help advance sleep and circadian timing. These interventions can also be scaled without having to purchase bright light glasses or light-blocking glasses. Increasing environmental morning light and decreasing evening light at home can be helpful strategies for night owls trying to adapt to an earlier schedule. These promising findings are from a small pilot study and must be replicated in a larger randomized controlled trial to further evaluate their effectiveness.
Delainey Wescott, MS, University of Pittsburgh
