SEASONAL AFFECTIVE DISORDER

Introduction

Seasonal Affective Disorder (SAD) was defined in the early 1980s (Rosenthal et al. 1984) but the concept of seasonal depressive illness has been acknowledged for over 2,000 years. SAD is now widely recognised amongst medical practitioners, although experience of treatment is limited.

Symptoms

Some or all of the following symptoms may be present:

• mood depression
• guilt
• low self-esteem
• hopelessness
• apathy
• emptiness
• loss of feelings
• irritability
• avoidance of human contact
• anxiety
• inability to tolerate stress
• depersonalisation
• obsessionality
• paranoid thoughts
• hypomania
• elated mood
• hyperactivity
• decrease in sleep
• grandiose ideas
• vegetative fatigue
• lethargy
• debility
• sleep problems (usually hypersomnia and difficulty staying awake, sometimes disturbed sleep and early morning wakening)
• carbohydrate craving
• hyperphagia and weight gain
• decreased libido
• low body temperature
• muscle aches and pains
• cognitive poor memory
• poor concentration
• intellectual and motor retardation
• other lowered immune function and resistance to illness
• menstrual difficulties

Diagnosis

Three winters of symptoms, two of which should be consecutive, with remission in summer, are the main criteria for diagnosis. Patients whose depressive symptoms are disabling from November to March, and who cannot function without medical treatment may be diagnosed as SAD. Those whose symptoms occur mainly from January to March and in whom vegetative symptoms occur where depressive symptoms are mild or absent, can be diagnosed as sub-syndromal SAD. SAD can be categorised as unipolar (no hypomania), bipolar II (hypomania in spring and sometimes autumn) or bipolar I (summer mania).

Recurrence of symptoms may occur in summer during dull weather, or where there is extreme cloud cover.

The Seasonal Pattern Assessment Questionnaire (SPAQ) and the Structured Interview Guide for the Hamilton Depression Rating Scale, Seasonal Affective Disorders Version (SIGH-SAD) are the recommended screening tools for SAD.

Differential diagnosis

Other conditions which should be considered include:

• non-seasonal major or recurrent depression
• bipolar or unipolar depression
• hypothyroidism
• hypoglycaemia
• chronic viral/post-viral illnesses (e.g. Epstein-Barr, ME).

There are cases where SAD is present in addition to a post-viral syndrome or continuous low level of mood disorder. The onset of SAD each year is nevertheless marked.

Family history

Studies have shown that up to 88 % of SAD patients have at least one family member with depressive or other psychiatric illness or alcoholism.

Age of onset

SAD symptoms can appear at any age. A recent survey (SADA 1993/94) showed that 32% started SAD between the ages of 22 and 35, the main age of onset for mood disorders, and 37 % below the age of 21. The remaining 31% were symptom-free until the age of 36, except for some women who had suffered post-natal depression, a known triggering factor.

Other possible triggering factors include severe/chronic illness (11 %), hormonal changes (e.g. menopause), hysterectomy (18%), and life events (e.g. retirement, loss of job, status, bereavement (14 %)).

Treatment

Light therapy is the most effective treatment (85 % success in diagnosed cases). Light fixtures cannot be prescribed on the NHS, but have been recognised by HM Customs & Excise as bona fide medical equipment, and can be purchased free of VAT.

Light is more effective in patients with characteristic SAD symptoms of hypersomnia and hyperphagia than those with typical depressive symptoms (e.g. poor sleep or appetite). The patient should begin treatment within two weeks of the onset of symptoms, and build up and maintain it throughout the period of illness. They should start with two hours per day at 2,500 lux intensity of light, and continue the treatment daily for two weeks. Improvement should show after 3 to 4 days, and should be complete after two weeks, at which time they can be advised on an increase or decrease of treatment time or duration, until an appropriate dose is found.

Many studies have shown that there is no optimum time of day to use light and that the user has to find their own. Some patients like to use treatment in one early morning session which sets them up for the day. For others, an hour in the morning and another hour in the early evening works well. Late evening should be avoided as it may prevent sleep.

High intensity light treatment (5000 to 10,000 lux) may be used for shorter periods, for a minimum of 30 to 45 minutes per day. This is especially useful for severe SAD patients who may require up to six hours per day at 2500 lux in the depths of winter.

Light treatment has been proved to be safe; the UV content of fixtures is small and mostly screened out. Occasionally, users may develop sore eyes or headaches after use. They should be advised to switch off the light source for a while or move it away. Anyone who has eye disorders or cannot bear bright light, will have to consider other means of treatment.

Medication can be used as an adjunct to light treatment, or when the patient cannot use sufficient light treatment. Antidepressant drugs alleviate depressive symptoms and may help with others. Tricyclics (TCAs) have not been found helpful in SAD, because they exacerbate the sleepiness and lethargy characteristic of SAD. The newer selective serotonin re-uptake inhibitors (SSRIs) have been found to be a vast improvement on TCAs, despite occasional gastro-intestinal side-effects.

One of the following should suit most patients (if one is found unsuitable, it is well worth trying either of the other two, as they are all different):

• sertraline (Lustral)
• paroxetine (Seroxat)
• fluoxetine (Prozac)

In cases where SSRIs are not suitable, monoamine oxidase inhibitors (MAOIs) have been effective; moclobemide (Manerix) is suggested.

Other psychotropic drugs are rarely necessary in the majority of SAD cases. Lithium, carbamazepine, and neuroleptics are only recommended in bipolar I illness. Benzodiazepines should only be used for extreme anxiety or sleep disruption until light treatment or SSRIs become effective.

Management

Sensitive management of SAD patients is vital. Many have feared doctors' reactions to their illness in the past and, despite increased awareness of SAD, still prefer to self-treat with light and obtain advice from SADA and the specialist clinics. Even when the depression is not severe, SAD is uniquely disabling. Once diagnosed, sufferers know that they will be ill and unable to cope with normal life every winter for the rest of their lives. This is incredibly disrupting and many normal aspects of life become difficult: work; relationships; family; friends; finances. Psychotherapy or counselling can help them to accept and learn to cope with their illness and its repercussions, but regular support and reassurance from their GP or psychiatrist can save patients from despair or even suicide, particularly in February and March when they are getting to the end of their tether and are too apathetic and full of self-doubt to help themselves.

References

1. Winter Blues by Norman Rosenthal M.D. Guilford 1993 (contains SPAQ screening tool)
2. Seasonal Affective Disorder ed.Thompson/Silverstone. CNS Neurosciences 1989
3. Seasonal Affective Disorders & Phototherapy ed.Rosenthal/Blehar. Guilford 1989