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A woman standing outside in the winter staring into the distance across a lake. The text reads: "Seasonal Affective Disorder (SAD): wintertime blues and summertime sadness."

Seasonal Affective Disorder (SAD): Wintertime Blues and Summertime Sadness

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What is Seasonal Affective Disorder?

Seasonal Affective Disorder (SAD) is a condition where people experience depression seasonally. SAD is common in wintertime and in places where sunlight is particularly scarce, but, surprisingly, SAD occurs in the spring and summertime as well.

On the shortest day of the year, the Winter Solstice, Hoosiers experience only about nine and a half hours of sunlight. While most of us dream of more sunlight during the winter, some places get significantly less sunlight. In the northernmost city in the United States (Utqiaġvik, Alaska, formerly known as Barrow) residents experience more than 60 consecutive days of darkness each year!

Causes of Seasonal Affective Disorder

According to the Mayo Clinic, disruptions to our circadian rhythms can contribute to the onset of SAD. Circadian rhythms are our biological cycles connected to the 24-hour rotation of the earth (often simplified to our waking and sleeping cycle). SAD is also connected to a reduction in certain hormones and neurotransmitters like melatonin and serotonin.

Circadian Rhythms

The cues for our circadian rhythms shift throughout the year. Our bodies, through complex chemical interactions, have to accommodate these environmental differences with our need to sleep. During winter months, people often wake before sunrise and arrive home after the sun has set. This reduction in sunlight affects the onset of melatonin production.

If you aren't getting deep, restorative sleep, then you may benefit from a sleep supplement. Optimal REM Sleep from Optimal Health Systems can help you get higher quality sleep today. Use discount code OHS3BKINMAN for 10% off your supplement order or purchase it from Dr. Inman's office.


The mechanism for non-winter SAD is less clear since sunlight is far more abundant in summer months. When the sun stays up later into the evening, we're more likely to enjoy the extra sunlight which could correspond to shortened night cycles. Seasons affect us in many different ways and the subtle changes to our bodies can have big impacts on our mood.


Serotonin is a neurotransmitter that contributes to several biological functions. In its relation to SAD, serotonin plays a role in mood regulation. Most of the serotonin in our bodies is found in the digestive system while smaller amounts are found in our platelets and nervous system.


Vitamin D plays an important role in serotonin production. One form of vitamin D is created through exposure to sunlight. As seasons shift we are at risk of vitamin D deficiencies (through lack of sunlight) which can lead to a reduction in serotonin. 

You may benefit from vitamin D supplements, especially in the wintertime. Dr. Inman recommends Essential DAK1K2 or Optimal Longevi-D K2 from Optimal Health Systems. Use discount code OHS3BKINMAN for 10% off your total Optimal Health Systems order. Dr. Inman keeps these supplements in stock as well.

Be sure to follow the instructions on any vitamin D supplements since vitamin D is a fat-soluble vitamin, it can  become toxic if over-supplemented.

Genetic testing, through Functional Medicine, can inform you about how your body consumes certain neurotransmitters, like serotonin. Due to the complex interactions between our diet and our genes, you may have a healthy diet but still experience diet-related issues. With genetic testing and consultation with Dr. Inman, you can gather clues about your unique situation and figure out the root cause behind problems you may be facing.


A major hormone causally linked to SAD is melatonin. Melatonin is produced naturally in the human body and helps regulate our circadian rhythm. As the days become shorter, the onset of melatonin production starts earlier and lasts longer. 

Dr. Inman offers a high-quality melatonin supplement through Optimal Health Systems, order using discount code OHS3BKINMAN for 10% off or call her office to order yours today.

A field that's become more popular recently, chrononutrition, studies the interaction of our diet and our biological rhythms. Practically speaking, your ability to transition to sleep is affected by when and what you consume throughout the day. Warm milk and teas, like Dr. Inman's Vitalitea Dreams, affect melatonin production and can help you transition to sleep.

Another tool that can help regulate sleep is the BrainTap device. BrainTap uses a combination of sound and light to relax and recharge you through an experience similar to meditation. 

While using the BrainTap headset is optimal, you may also benefit from audio-only sessions provided by BrainTap. Through a partnership between Dr. Inman and BrainTap, you can try the audio version of BrainTap free for 30 days

As a bonus, if you take advantage of the 30-day free trial you'll also receive a free eBook: Thrive in Overdrive: How to Navigate Your Overloaded Lifestyle.

Holistic Wellness and Seasonal Affective Disorder

Seasonal affective disorder varies in severity and if you find yourself experiencing depression during certain seasons you may be affected. Severe SAD may need to be treated with antidepressants or other medications, so seeking the advice of a medical professional is warranted.


Holistic wellness is whole body wellness. It's about understanding what mix of nutrition, exercise, and supplementation makes you feel the best and helps you reach your health goals. Our bodies are complex systems and it can take lots of trial-and-error to get it right. With Dr. Inman's help, you can start on your path to wellness and create a holistic plan for a healthy life.

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