Depression or Seasonal Affective Disorder (SAD)?

As a nation, we are often deprived of sunshine, even in the summer months. Most of our vitamin D is produced through direct exposure to the sun, hence why it is also known as the ‘sunshine vitamin.’ Vitamin D is a steroid hormone precursor and thought originally to only play a role in the mineralisation of bones and teeth by maintaining the correct phosphorous/calcium ratio. More recently, however, research has linked low levels of vitamin D with obesity, diabetes, cardiovascular and autoimmune diseases, osteoporosis, cancer and the third largest cause of morbidity here in the UK - depression.

The lower the level of Vitamin D, the greater the risk of depression. The big question is still causality. Does one get depressed because of a deficiency of Vitamin D, or does depression lower the vitamin level itself?

Depression affects one in four of us in the UK, yet previous conservative estimates suggested that Seasonal Affective Disorder (SAD) affects as few as 3% and 5% of us, with one in eight (12.5%) having the more mundane ‘winter blues’ - a much less well-defined change in mood. Yet according to more recent research commissioned by the weather channel and YouGov, a staggering 29% of adults experience symptoms of SAD.

For those not already aware, SAD is a mood disorder subset in which people who have normal mental health throughout most of the year, can experience depressive symptoms at the same time each year, most commonly during the autumn/winter months.

According to the expert in such matters, Dr Sarah Jarvis, to have genuine SAD, a person must have suffered depression two years running. Winter blues often involves lack of sleep, while SAD means people are permanently tired and spend longer in bed.

So what are the Symptoms of SAD?

• A persistent low mood.
• A loss of pleasure or interest in normal everyday activities, including sex.
• Irritability.
• Feelings of despair, guilt and worthlessness.
• Feeling lethargic (lacking in energy) and sleepy during the day.
• Sleeping for longer than normal and finding it hard to get up in the morning.
• Craving carbohydrates and gaining weight.

For some people, these symptoms can be severe and have a significant impact on their day-to-day activities.

So can we do anything to help ourselves?

There are a range of treatments available for SAD. Your GP will be able to recommend the most suitable for you. These include:

• Lifestyle measures: getting as much natural sunlight as possible, exercising regularly and managing your stress levels better.
• Light therapy: where a special lamp called a lightbox is used to simulate exposure to sunlight.
• Talking therapies: such as cognitive behavioural therapy (CBT) or counselling.
• Antidepressant medication: such as selective serotonin reuptake inhibitors (SSRIs).
• St Johns Wort: a natural herbal remedy thought to be effective for depressive symptoms including SAD.
• Diet and nutrition: eating more oily fish, red meat, liver, egg yolk, fortified foods such as most fat spreads and some breakfast cereals.
• Vitamin D supplement: Public Health England (PHE) recommend that we all take a daily supplement containing 10mcg of Vitamin D between the months of October-March.

It is important for each of us to be able to differentiate the symptoms of SAD from the more chronic long-term and debilitating condition - depression. While symptoms may be similar, people suffering with SAD can take some comfort in the knowledge that life will feel easier to manage by adopting some simple therapies available, such a sitting in front of a lightbox for 20 minutes a day and/or making time to get outdoors and enjoy a brisk 20 minute walk three to five times per week.