How does SAD relate to circadian rhythms?

• A. It follows a monthly cycle
• B. It affects only daytime activities
• C. It is caused by disruptions in the sleep/wake cycle
• D. It has no relation to circadian rhythms

Answer: (C)

Seasonal Affective Disorder (SAD) is closely tied to circadian rhythms, particularly due to how exposure to light regulates mood and biological processes. Circadian rhythms are the internal biological clocks that follow approximately a 24-hour cycle, influenced mainly by natural light. In individuals with SAD, the reduction in daylight hours during certain seasons can disrupt these rhythms, leading to altered sleep/wake cycles.

When the amount of natural sunlight decreases, it can affect melatonin and serotonin levels, neurotransmitters that play important roles in mood regulation and sleep patterns. These disruptions can result in symptoms associated with SAD, such as depression, lethargy, and changes in sleep patterns. Therefore, the relationship between SAD and circadian rhythms is significant, as the disorder often manifests due to these changes in the natural sleep/wake cycle influenced by seasonal variations in light exposure. This connection underscores the importance of maintaining healthy circadian rhythms to mitigate the effects of SAD.