Seasonal affective disorder (SAD) is a form of depression associated to changes in the seasons (often worse in the winter). Symptoms of SAD include mood swings, anxiety, withdrawal, disturbed sleep, lack of energy and loss of sex drive. Seasonal affective disorder is attributed to lack of daylight that prevents chemical production by the hypothalamus part of the brain. SAD sufferers have lower levels melatonin and serotonin chemicals that help regulate sleep, mood and appetite.

Causes of seasonal affective disorder

SAD is linked to a lack of exposure to sunlight during the shorter winter days. Although seasonal affective disorder has no clear cause, there are significant factors which trigger the condition.

Part of the brain called the 'hypothalamus' helps to control mood, appetite and sleep and is thought to be stimulated by light. For somebody with SAD, a lack of light prevents the hypothalamus from functioning correctly leading to low mood, sleeping difficulty and a loss of appetite.

Certain chemicals and hormones can also trigger SAD. Melatonin, the hormone which regulates sleep, is produced by the pineal gland. When there is less light, the body produces melatonin to help with sleep. When there is more light, the pineal gland produces less melatonin to wake the body up. Somebody with SAD produces higher levels of melatonin during the winter.

A chemical called 'serotonin' regulates mood, appetite and sleep and someone with SAD typically has lower levels of serotonin during the winter. When sunlight is reduced, less serotonin is produced.

Another factor which can trigger seasonal affective disorder is a psychological process known as the 'circadian rhythm'. The body has an internal clock which regulates when to sleep and when to wake up. Reduced sunlight can disturb the circadian rhythm leading to a disruption that is linked to feeling depressed.

Some experts have conducted research which has suggested that SAD may be a genetic disorder and if a close family member has the condition the chances of inheriting it are one in seven.

Seasonal affective disorder (SAD) appears at the same time each year (usually the autumn) and then goes away as sunlight increases (usually around spring). Symptoms usually start as being mild and gradually worsen as sunlight decreases into the winter months.

Common symptoms of SAD include:

• Lack of energy
• Tiredness or lethargy
• Disturbed sleep
• Loss of libido (sex drive)
• Stress
• Anxiety
• Withdrawal from social activities
• Sadness
• Increased appetite or loss of appetite
• Food cravings (carbs and sweets)
• Mood swings
• Weight gain
• Lack of concentration
• Disinterest in enjoyable activities

• Anxiety
• Sleeping difficulties
• Mood swings
• Irritability
• Weight loss
• Loss of appetite
• Increased libido (sex drive)

There is no conclusive test to diagnose SAD but in the first instance you should visit your GP. The GP will perform a physical examination to rule out any underlying health problems which may be causing your symptoms.

The GP will then carry out a psychological assessment and ask questions about your mood, diet, sleeping patterns and changes to thoughts and behaviour during the seasons.

The symptoms of SAD are similar to other mental health conditions such as depression and it may take the GP a while to identify if the symptoms are triggered by a regular seasonal pattern. A diagnosis will depend on whether you have experienced symptoms for two consecutive years or more and if periods of low mood are followed by periods of feeling balanced.

Associated symptoms of depression include weight loss, loss of appetite and difficulty sleeping whereas SAD symptoms tend to be weight gain and excessive sleeping.

*Source: GoToSee.co.uk

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