Seasonal Affective Disorder (SAD) is a type of depression that can happen towards the end of the year as we reach Autumn and Winter.  It is linked to the reduced exposure to natural sunlight during the shorter and darker days for this time of year.

A method for treating SAD is light therapy and this has been found to be one of the most effective treatments for it.   It involves exposure to bright artificial light commonly labelled “Daylight” for their colour temperature. 

Understanding Daylight Lights(Full-Spectrum Lighting)

The term "daylight" typically refers to full-spectrum lighting.  This may also be described as 6000-6500k. These lights are designed to mimic the natural spectrum of visible light produced by the sun.  This also gives them a high Color Rendering Index (CRI).

The Difference Between General Lighting and Therapeutic Light Boxes

While full-spectrum daylight lights can improve the quality of indoor lighting and may positively affect a person's mood compared to standard warm-white bulbs, they are not a substitute for the specific treatment required for SAD.

1. Light Therapy Boxes (The Standard Treatment)

There are specialized light therapy devices called light boxes or SAD lamps which are clinically proven to treat SAD. They work by delivering a specific, high intensity of daylight light directly to the user.  Direct staring is not recommended with these but if it is a treatment you are prescribed you will be instructed on how to use it.

2. Do Daylight Lights Help?

Daylight lights will not work as a sole treatment for SAD and are not medically recommended as treatment but some have found it helps partially.  It is not recommended medically because:

• Insufficient Intensity: The key requirement for SAD treatment is 10,000 lux from the light. A typical daylight light will not emit more than 1000 lux.  
• Supportive Role: Full-spectrum daylight colour lighting can however be beneficial for overall well-being and visual comfort, especially in an area without windows.  They can help maintain a more alert, daytime productive atmosphere, which can have a supportive, non-therapeutic effect on a person’s mood.

Conclusion and Recommendation

While daylight coloured lights (full-spectrum lighting) are a great choice for improving the quality of light in your home or office, they should not be relied upon as a primary treatment for Seasonal Affective Disorder.

The recommended treatment remains a specialized light therapy box that provides the required 10,000 lux of light intensity, used daily under the guidance of a healthcare professional.  If you suspect you have SAD you should always consult a medical professional to confirm the diagnosis and they will recommend the appropriate treatment.