From Netdoctor

Seasonal affective disorder (SAD) is a type of depression that becomes more severe as winter approaches and daylight hours become shorter. Sometimes called ‘seasonal depression’, it affects one in three people in the UK throughout the colder months, and is characterised by a low mood that lasts for a long time and affects your everyday life. In the UK, up to 6% of adults have ‘recurrent major depressive episodes with seasonal pattern’ , and the mean age at presentation of SAD is 27 years with men and women being equally affected.

It’s common for our moods and lifestyle to be affected by the changing seasons. Our energy levels, eating habits, and sleeping patterns may change naturally when the weather is particularly cold or warm. But if you experience persistent low feelings that tend to set in around the same time each year, it could be a sign of seasonal affective disorder.

We spoke with pharmacist Navid Sole, of Peter’s Pharmacy, and Dr Chun Tang, general Practitioner at Pall Mall Medical, to find out more about the causes, symptoms and treatment options available for seasonal affective disorder:

What is seasonal affective disorder?

Seasonal affective disorder is a form of depression related to the changing of the seasons, says Dr Tang, ‘most commonly when the summer turns into winter.’ Because it relates to a change in weather, seasonal affective disorder is often a recurring issue, and can affect an individual every 12 months. ‘Patients often begin experiencing symptoms of depression during autumn and often do not feel an improvement in mood until the spring,’ he says.

Seasonal affective disorder causes

While little is known about the mechanisms behind seasonal affective disorder, it appears to be linked to reduced exposure to sunlight and shorter days, says Sole. ‘The main theory that doctors have developed is that the reduced sunlight and levels of vitamin D might decrease [activity] in the part of the brain called the hypothalamus,’ he explains. The hypothalamus is responsible for releasing hormones, regulating emotional responses, and maintaining your internal body clock, known as circadian rhythm.

Research has shown that light exposure can impact the hormones and chemicals found within the brain, says Dr Tang. ‘Without sufficient sunlight, serotonin and melatonin – the chemicals that produce feelings of joy and happiness – can be negatively affected,’ he says. ‘This is why during the months of colder, duller and shorter days patients who suffer with seasonal affective disorder often report feelings of depression.’

Seasonal affective disorder symptoms

Seasonal affective disorder is associated with a number of symptoms. They can be severe and have a significant impact on your day-to-day life. They include:

• Persistent low mood
• Loss of interest in usual activities
• Feeling irritable
• Feelings of despair, guilt, or worthlessness
• Low self-esteem
• Tearfulness
• Feeling anxious
• Withdrawing from social occasions
• Reduced sex drive
• Feeling lethargic
• Sleeping longer than normal
• Increased appetite, especially carbohydrates
• Weight gain

While depression and seasonal affective disorder share the same symptoms, there are key differences in terms of triggers and longevity. Where seasonal affective disorder is caused by a change in seasons, ‘depression can be caused by a variety of triggers such as stress, bereavement and trauma,’ says Dr Tang. ‘An individual who suffers from seasonal affective disorder will often have better mental health during the summer months, whereas an individual with depression can be affected during any time of the year.’

When to see your GP

‘An individual should visit their GP when their low mood is prolonged and begins affecting their daily life,’ says Dr Tang. They will be able to help if your mindset is affecting your sleep hygiene, eating habits or energy levels, or if you’re experiencing feelings of worthlessness, despair or suicidal thoughts, he says.