Most people think of daylight saving time as little more than an annoyance. Twice a year, clocks move forward or backward by one hour, disrupting schedules and causing temporary sleep loss. Many people assume the effects disappear after a day or two.
However, researchers are increasingly discovering that the consequences may extend much further, particularly for people living with mental health disorders.
A new study conducted by scientists from New Mexico State University and the University of Nevada, Las Vegas suggests that daylight saving time may pose a significant public health concern. Their findings were published in the journal Brain Sciences and were based on a review of more than 60 scientific studies from around the world.
The researchers examined evidence from several fields, including sleep medicine, psychiatry, neuroscience, chronobiology, and public health. Together, these studies paint a consistent picture. The sudden one-hour time shift appears to disrupt the body’s natural biological timing system in ways that can negatively affect mental health.
The human body operates on an internal 24-hour clock known as the circadian rhythm. This system helps regulate when people feel awake, sleepy, hungry, energetic, or emotionally balanced. Light exposure, especially sunlight in the morning, helps keep this clock synchronized with the environment.
When daylight saving time begins or ends, the relationship between the clock on the wall and the body’s internal clock changes suddenly. Although one hour may not sound like much, the brain does not instantly adapt. For some people, this mismatch can trigger sleep disturbances and emotional difficulties.
The researchers found that individuals with chronic mental health conditions appear to be particularly vulnerable. These include people with depression, bipolar disorder, anxiety disorders, PTSD, ADHD, and psychotic illnesses.
Many of these conditions are already associated with disrupted sleep and circadian rhythms, which may make patients more sensitive to clock changes.
Even short-term sleep disruption can affect mood, concentration, emotional control, and decision-making. In vulnerable individuals, these changes may contribute to worsening symptoms. The study suggests that daylight saving time may create predictable periods when mental health problems are more likely to intensify.
The researchers argue that healthcare professionals should treat daylight saving time transitions as risk windows that can be anticipated and managed. Instead of waiting for symptoms to worsen, clinicians may be able to help patients prepare beforehand.
Simple measures could make a difference. Gradually adjusting sleep schedules before the clock change may reduce circadian disruption. Spending time in bright morning light can help the brain adjust more quickly. Increased monitoring and support for high-risk patients during transition periods may also help reduce negative outcomes.
The findings add to a growing body of evidence questioning the value of seasonal clock changes. While daylight saving time was originally promoted for economic and energy-saving reasons, modern research has found limited support for many of these benefits.
At the same time, studies have linked clock changes to higher rates of accidents, injuries, cardiovascular events, and sleep-related problems.
According to the researchers, permanent standard time may offer a healthier alternative. Standard time aligns more closely with the natural cycle of sunlight and darkness, helping support the body’s biological rhythms. In contrast, permanent daylight saving time could increase the mismatch between social schedules and natural light exposure.
The debate over daylight saving time continues in many countries. While some governments have considered ending seasonal clock changes, no widespread agreement has yet been reached. Studies like this may influence future discussions by highlighting the possible mental health consequences of continuing the practice.
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Source: New Mexico State University.
