S.A.D is triggered by the increased production of the hormone Melatonin as it gets dark, this triggers our desire to sleep and is why people struggle to awaken on dark winter mornings. A lack of light also reduces the bodies production of a neurotransmitter called serotonin which has then been shown to contribute to feelings of depression.

There is no exact reasons behind the causes of SAD, but some of the causes of SAD include:

• Fewer daylight hours may reduce important mood altering chemicals in the brain;
• Hormonal disruption (cortisol, thyroid)
• Reduced retinal sensitivity to light,
• Low winter temperatures may trigger the body to rest and disrupt circadian rhythms;
• Barometric pressure and precipitant levels,
• Psychological mechanisms and personality traits may all be contributing factors.

Left untreated SAD can have serious impact on social, educational, and work activities as its emergence coincides with a traditionally more demanding period of societal expectations. If you think you may be suffering from SAD, you should seek medical advice.