What is the mechanism by which light therapy is believed to affect mood?

• A. Increases melatonin levels
• B. Mimics outdoor light to influence brain chemicals
• C. Decreases serotonin production
• D. Alleviates physical activity levels

Answer: (B)

Light therapy is believed to influence mood primarily by mimicking outdoor light to affect brain chemicals that regulate mood and emotions. Natural sunlight has a profound impact on the body’s circadian rhythms, and exposure to bright light is thought to enhance the production of neurotransmitters such as serotonin, which is often referred to as a "feel-good" chemical. This increase in serotonin can lead to improved mood and energy levels.

During darker months or in regions with limited sunlight, the disruption in natural light can lead to deficiencies in serotonin, resulting in seasonal affective disorder (SAD) and other mood-related issues. Light therapy provides a controlled source of bright light, thus simulating the effects of natural sunlight, which in turn helps to restore normal levels of these brain chemicals, thereby positively influencing mood.

Other options do not align with the established understanding of how light therapy works. For instance, increases in melatonin are typically associated with darkness and sleep initiation rather than mood elevation. Additionally, light therapy does not decrease serotonin production; on the contrary, it is believed to help increase serotonin levels. Alleviating physical activity levels is also not directly linked to the mechanisms by which light therapy affects mood but could be considered a separate factor in overall well-being.