Introduction

Seasonal affective disorder (SAD)is a type of depression that comes and goes in a seasonal pattern.

SAD is sometimes known as "winterdepression" because the symptoms are more apparent and tend to be more severe during the winter.

The symptoms oftenbeginin the autumn as the days start getting shorter. They're typically most severe during December, January and February.

SAD often improves and disappears in the spring and summer, although it may return each autumn and winter in a repetitive pattern.

Symptoms of SAD

Symptoms of SAD can include:

• a persistent low mood
• a loss of pleasure or interest in normal everyday activities
• 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
• cravingcarbohydrates and gaining weight

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

They mayask you about your mood, lifestyle, eating habits and sleeping patterns, plus any seasonal changes in your thoughts and behaviour.

The main theory is thata lack of sunlightmight stop a part of the brain called the hypothalamus working properly, which may affect the:

• production ofmelatoninmelatonin is a hormone thatmakes you feel sleepy; in people with SAD, the body may produce it in higher than normal levels
• production of serotoninserotonin is a hormone that affects your mood, appetite and sleep;a lack ofsunlightmay lead to lower serotonin levels, which is linked to feelings of depression
• body's internal clock (circadian rhythm) your body uses sunlight to time various important functions, such as when you wake up, so lower light levels during the winter may disrupt your body clock and lead to symptoms of SAD

It's also possible that some people are more vulnerable to SAD as a result of theirgenes, as some cases appear to run in families.

TreatmentsforSAD

A range of treatments are available for SAD. Your GP willrecommend the most suitable treatment programme for you.

The main treatments are:

• lifestyle measures, including getting as much natural sunlight as possible, exercising regularly and managing your stress levels
• light therapy where a special lamp called a light box is used to simulate exposure to sunlight
• talking therapies, such ascognitive behavioural therapy (CBT) or counselling
• antidepressant medication,such as selective serotonin reuptake inhibitors (SSRIs)

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