Many people living in temperate countries experience changes in their sleep patterns, energy levels and mood in the autumn and winter months. Whilst most people will feel ‘low’ at some point during their life, this feeling of unhappiness can develop into a depressive illness called seasonal affective disorder, commonly known as SAD.

SAD affects more women than men and mainly people aged from 20-30, although it can develop at any age. People who live in northern Europe, Canada and Scandinavia also suffer more because the distance from the equator means the number of daylight hours are less and the weather is generally cooler. Mild forms of SAD are sometimes referred to as the ‘winter blues‘ but people can also get SAD in the summer months, though this is much less common.

SAD symptoms to look out for
The symptoms of SAD can vary from person to person and are similar to those that can develop into other types of depression. Most common symptoms include:
• Experiencing a low mood for most of the day
• A greater need for sleep and sleeping more than usual
Eating more than normal and especially craving carbohydrates
Weight gain
Irritability and mood swings
• Excessive energy in spring/summer

Causes of seasonal affective disorder
Although the exact cause of SAD isn’t known, there are a few theories including the amount of sunlight experienced and genetics.

The amount of sunlight that we are exposed to affects the level of certain chemicals and hormones in the brain. The chemical called serotonin plays a key role in lifting our moods and people who suffer with SAD have abnormally low levels of chemicals such as this in winter. The hormone called melatonin slows down our body clocks and this affects sleeping and mood patterns. People with SAD may respond to a decrease in light by secreting more of the hormone melatonin than people without SAD.

Research has also shown a family link between people who have SAD, revealing that if you have a close relative who has suffered from SAD then you are more likely to develop it too.

Treatments for SAD
Having one spell of the ‘winter blues’ doesn’t automatically mean that you have SAD. When you initially visit your doctor you will be asked lots of questions about your day-to-day life and whether you have suffered any symptoms of depression in the past.

Once other forms of depression and illnesses have been ruled out there are several self-help treatments that can be implemented, such as:
• Changing your living and working environments to include more light and sit near a window if possible
• Make time each day to be outside, especially when sunny
• Take regular exercise
• Eating a well-balanced diet
• Let your family and friends know about your condition so they can offer help and support
• Join a local support group if available
• Using light therapy in the form of a light box to replace bright summer light to stimulate a change in hormones and chemicals

In severe cases doctors may recommend a course of antidepressant medication to be taken during the autumn and winter months only. An alternative to medication is cognitive behavioural therapy (CBT), which usually involve sessions with a therapist to help people manage issues by changing the way they think and behave.