Yuletide Blues: 'Tis The Season

Article by Dr Jeff Foster, GP

Most of us have heard of the medical condition seasonal affective disorder (or SAD) or, more informally, the winter blues. But while its existence may now seem obvious, the ‘official’ origin of SAD only dates back to the late 1970s.

At this time, the American researcher Herb Kern (based at the National Institute of Mental Health in Maryland) used himself as a guinea pig, convinced that his own depression was made worse in the winter months than in the summer.

Kern (and two other researchers, Alfred Lewy and Sanford Markey) came up with the hypothesis that the longer nights of winter increased levels of melatonin, which had the effect of triggering or exacerbating Kern’s depression. To confirm this idea, they set up a simple light box to shine light into Kern’s eyes twice a day, and within a week Kern had reported his symptoms improving.

From this point on, not only was the condition of SAD recognised, but so was one of its most commonly used treatments.

Since the 1970s, awareness and diagnosis of SAD have increased dramatically. Even so, could we be more prone to depression in winter because we spend our time working in offices, maintaining the same social clock regardless of the time of year and directly fighting our biological urges, which are actually trying to get us to shut down and hibernate until spring?

Seasonal Affective Disorder

The Royal College of Psychiatry states that 3% of the UK population have some form of significant winter depression. However, while many medical resources are quick to highlight the similarities between SAD and general depression, there are in fact several differences between the two conditions.

Both depression and SAD patients tend to suffer with the following:

• low mood

• lack of interest and enjoyment in life, work, and hobbies

• decreased energy

• not wanting to socialise

• being grumpy or more irritable

• decreased interest in sex.

Patients with depression also tend to have disturbed sleep patterns (difficulty getting to sleep, staying asleep or waking early) and often have a reduced appetite. The opposite is seen in SAD, where patients often only want to be awake during daylight hours.

In addition, SAD patients often have an increased appetite, generally craving higher calorie foods. Although the symptoms of increased sleep and increased appetite are not always seen in SAD, they can be important symptoms that help differentiate between SAD and general depression.

Interestingly, SAD does tend to follow other types of depression in terms of patient demographics. It is most common in women of childbearing age, and it is about three times more common in women than in men.

SAD is rarely seen in children; it also becomes less common in older adults, where the prevalence becomes the same in both sexes.

Pathophysiology

There is no accepted reason why some people develop SAD. The common hypothesis is that a lack of daylight promotes disturbances in melatonin production, which, in some way, results in the exacerbation or triggering of a depressive state. It has been suggested that some people are more prone to SAD because they are less responsive to light, and that spending too much time indoors triggers their condition.

Other theories include the idea that all humans still function via an evolutionary biological clock, which tries to get us to become more sedate and lethargic in winter, so as to conserve energy in the cold weather when food is scarce.

The ‘phase-shift hypothesis’ suggests that the later sunrises in winter cause a delay in our internal biological rhythms, so that they are no longer in tune with when we go to sleep and when we wake up. Many people tend to have moods that follow a circadian rhythm: we wake feeling irritable and become cheerful during the day, before our mood declines again overnight. If our circadian rhythm becomes misaligned with the actual time of day, our low mood may be more prominent in the daytime.

Treatment of SAD

Because there is no accepted theory on why some people develop SAD, treatment tends to follow the same principles as for general depression, with a few significant differences.

Light Therapy

Despite the apparent success of light therapy in treating Herb Kern’s SAD, and subsequent promotion and selling of light boxes in SAD therapy, the evidence for this form of treatment is inconclusive. Standard light therapy is usually used for 30 minutes to an hour each day. It is considered to be most beneficial when used early in the day, and some researchers have found that the improvement in symptoms is rapid.

Interestingly, a Cochrane review from 2018 found that no studies have provided any good quality evidence for the successful treatment of SAD with light therapy.

Medication

Seasonal use of antidepressants remains a major treatment choice for SAD. The principles of antidepressant use in SAD follow that of antidepressant use in generalised depression. Medication is designed to reduce feelings of tiredness and improve mood. Importantly, unlike light therapy, a Cochrane review from March 2019 demonstrated a reduction in clinical symptoms in some patients who took specific forms of antidepressants. The majority of SAD patients, however, still demonstrate limited success from medication.

Talking Therapies

Adjunctive psychotherapy may increase adherence to lifestyle measures and medication and reduce distress. In general, cognitive behavioural therapy (CBT) is recommended as a first choice for supportive treatment of SAD. It is worth noting that access to CBT can be difficult, and the therapy itself often takes months to be effective.

Lifestyle

One of the treatment options in SAD that is often poorly addressed is lifestyle management. In particular, it is important to stress to patients with SAD that they should spend quantifiable time outside, improve their diet and exercise where possible, and make a conscious effort to socialise. It is these lifestyle measures that are so often skirted over as ‘understood’, or too hard to address fully in a standard 10-minute primary care consultation.

However, by effecting real change in a patient's day-to-day activity, it can have significant benefits in reducing the symptoms of SAD.

Unfortunately, no studies have compared the different forms of treatment for SAD. It is concerning, however, that despite there being only anecdotal evidence for the success of light therapy, it is still widely promoted in medical information resources and is widely sold as a treatment option. Overall, the treatment of SAD has to be based on the individual patient and a mutual discussion about their preferences for certain types of therapy alongside the associated risks and benefits.

Summary

Overall, theories on the development of SAD suggest that this disease is one we have made for ourselves: a consequence of our artificial, computer-driven work and social environments. Significantly, the pathophysiology and treatment of SAD have progressed very little since its discovery in the 1970s.

Perhaps we need to approach SAD rather as we deal with the treatment of obesity or type 2 diabetes; that is, to think of it more as a consequence of the social networks and lifestyles we have constructed for ourselves. In the meantime, while we are searching for a solution to this problem, maybe we should all think of owning a light box.

Dr Jeff Foster

www.drjefffoster.co.uk

Dr Jeff Foster is a GP with an interest in Men's Health. If you have any questions on men's health, please contact Dr Foster at contact@drjefffoster.co.uk