What is SAD?

Feeling SAD this winter?

Feeling blue this winter? You’re not alone, 3% of the UK population report feeling low during the winter months. Today’s article in the mood series is focusing on SAD – seasonal affective disorder.

What is SAD?

SAD is a seasonal form of depression which is experienced during the autumn-winter months of the year. It’s thought to affect around 3/100 people with the majority of people being in their early 20-30s. Statistics show that women are x4 as likely to experience SAD than men. It goes without saying that this doesn’t mean other age groups or men don’t also suffer from SAD.

The main difference between standard depression and seasonal depression is that SAD only surfaces during the winter months. Therefore, if you notice that your sleeping, eating and mood demonstrate changes during these months then SAD is a more likely diagnosis.


Here are some symptoms of SAD, according to the NHS:

  • Craving for carbohydrates
  • Weight gain
  • Loss of interest or enjoyment in activities that previously bought joy
  • Lack of energy
  • Persistently low mood
  • Restlessness and Irritability
  • Changes in sleep routine
  • Finding it hard to get up in the morning

Be mindful that a lot of these symptoms cross over with other diagnoses so it’s important to receive a conformation diagnosis from your healthcare practitioner or GP.

Suspected cause of SAD

There is no one cause for SAD and scientists and Doctors have not confirmed which they believe is the plausible explanation for this. However, there are a number of theories:

  • Lack of Vitamin D – As we know from previous articles, humans' best source of vitamin D is their skin. To recap we contain the inactive form of vitamin D in our skin which we convert using sunlight into active vitamin D3. In the northern hemisphere, and during the winter months, we are unable to make this conversion which can leave many of us deficient in Vitamin D. Among many things, Vitamin D is associated with mood stability. One of the common symptoms of vitamin D deficiency includes changes in mood and depression.
  • Disruption of our circadian rhythm- due to the shortened days in winter, our circadian rhythms may be disrupted. For more details on this check out Tuesday’s article on Mood and Lifestyle. In short, circadian rhythms are cyclical patterns that govern our sleep-awake and eating cycles. Our body uses natural light and lack of natural light to dictate these cycles. Because the days shorten, and the nights seem longer this can disrupt our sleep cycle and induce feelings of SAD.
  • Increased production of melatonin- Melatonin is our sleep hormone. As mentioned above, melatonin is involved in our circadian rhythm. Throughout the day, and as light dims our body naturally starts to produce melatonin. However, because of the longer nights, melatonin may be much higher in people with SAD.
  • Decreased production of serotonin- Serotonin is the happy hormone. For more information on serotonin, you may like to revisit the article from day 1 of this week. It’s thought that for people suffering with SAD there may be a decreased production or reaction to serotonin.

What to do if you think you have it?

We recommend that you get a professional's opinion. In the current climate, low mood could be caused by quite a few environmental, social or physical factors.

The NHS website suggests that your GP will conduct a full assessment of your mental health. This may include asking about your lifestyle, eating and sleeping habits, from this they will make a diagnosis and care plan.

Lifestyle recommendations and treatments


One recommendation by the NHS is to look at the way you approach your lifestyle. Looking at your sleep hygiene, exercise routines, nutrition and stress levels. For more information check out Wednesday’s article.

Light Therapy

This works off the idea that SAD can be caused by a change in natural light and disruption of the circadian rhythms. You can buy lights or alarm clocks that mimic natural sun light in order to overcome this. This helps the body slowly adjust and reset its circadian rhythm. Evidence has shown that light therapy can help to mimic natural sunlight, so much so that the body will begin to produce beneficial hormones related to sleep and mood.

When shopping for a lightbox, be mindful to opt for a light that has filtered out UV rays. UV lights can be harmful to eyes and skin if not properly managed.

Talk Therapies

For any form of depression talking therapies are a great option. This may include cognitive behavioural therapy or counselling to manage the changes and symptoms that you are facing. This option is often offered over the phone or in person.Antidepressants

This is something that can be discussed with your GP. Antidepressants are a medication only given on prescription by a qualified healthcare professional. The most common antidepressants given are a type of selective serotonin reuptake inhibitors.

Vitamin D

Lastly, is the option of taking vitamin D as an additional form of therapy. Yesterday’s article discussed this at length if you want to read about it further. One study that discusses the effect of vitamin D on mood gave two groups either a 600iu or 4000iu supplement. Then, they measured their depressive symptoms via a questionnaire before and after their 3-month supplementation. The results showed that there was a significant improvement in wellbeing (measured by the questionnaire) following vitamin D supplementation through the months of December to February. As expected, the group receiving the higher dosage of 4000iu had a greater response. One cross-sectional study looked at Vitamin D and its association with major depressive disorder (MDD). The review looked at 13 studies, of those 12 found a positive effect on symptoms with vitamin supplementation.

Remember that you are not alone in your SAD journey. There are many other people feeling the exact same way. Reach out to friends, family and most importantly your GP for support.

If you are enjoying our mood series so far, don’t forget to check out yesterday’s article on nutrition and mood. In tomorrow’s instalment we will announce our mood series competition – watch this space!


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