Seasonal affective disorder: what is it, and how can I avoid it?

There is a reason many of us in the northern hemisphere find ourselves dragging our feet through January and February, and not just because we’re on a comedown from the festivity of December holidays. With our daylight hours at a minimum, bookended by darkness late into the mornings and early in the evenings, many of us find our moods seem to shift towards darkness, too.

Feelings of lethargy and depression arise in tandem with the low light of winter. It gets harder to rouse ourselves from sleep, as we open the blinds to find, aghast, that the sun hasn’t risen despite the day having already begun. So what should we make of the sluggishness that inevitably finds us on a seasonal basis? 

What are the symptoms of SAD?

Firstly, we should know we’re not alone. The affliction known as seasonal affective disorder, aptly shortened to the acronym SAD, is an episodic ‘winter depression’ that impacts roughly 5% of adults in the US every year. SAD is a seasonal variation of major depressive disorder (MDD), marked by a noticeable dip in mood and motivation in accordance with the decrease in daylight hours during winter months.

Symptoms are similar to those of major depressive disorder, including a loss of interest in favoured activities, feelings of hopelessness, a lack of energy or will to get out of bed in the morning, and overall low mood. People with SAD can experience symptoms just as severe as those suffering from MDD. Where the two disorders differ, however, is in their timing, as those suffering from SAD tend to experience episodes on a cyclical, seasonal basis. 

Why does SAD occur?

SAD can occur for a number of reasons, but it is mainly attributed to our physical responses to the lack of daylight hours in winter. Whether we are aware of it or not, our hormonal reactions to daylight are what regulate our circadian rhythms, impacting everything from blood pressure to metabolism to mood. This internal, 24-hour clock picks up cues from our environment, namely light, to regulate our cycle of sleep and wakefulness, among numerous other bodily processes.

At its most basic, light influences our ability to see our surroundings, to observe beautiful flowers and watch stupid horror films and read the words on this page. Beyond that, though, sunlight does something special to our emotions, triggering the release of a hormone called serotonin. That’s the ‘happy hormone’, responsible for stabilising our moods, reducing depression and anxiety, and making sure we’re getting the right amount of sleep. Light exposure tells our brains to stay alert, promoting wakefulness, and the fall of darkness prompts our brains to produce melatonin, the chemical that makes us sleepy.

Naturally, shorter days means less light, which means a disruption in our bodies’ 24-hour clock. Less light means less access to the happy hormone and less sleep regulation, so we find ourselves more tired and groggy than usual.

Because SAD is so dependent on rhythms of daylight, certain geographic locations are more affected than others. Those living in northern climates where daylight hours are most drastically reduced during the winter season are hit particularly hard. In Norway, where the sun only shines for six to eight hours in winter, SAD affects 14% of the population, according to a study by Dr Norman Rosenthal of the National Institutes of Mental Health.

Like plants without sunlight to photosynthesise into energy, we are prone to withering in prolonged darkness. Those of us in northern places are therefore more vulnerable to SAD, but we aren’t totally doomed to suffer from it. 

What are the treatment options for SAD?

I believe it was the sagacious Hogwarts Headmaster Dumbledore who said, “Happiness can be found, even in the darkest of times, if only one remembers to turn on the light.” Indeed, even in the darkest of January days, when the sun rises at the appallingly late hour of 9am and sets at a disgustingly early 4pm, we can redeem ourselves by turning to the light that we do have. 

According to a study from Northwestern University led by Northwestern Medicine Neurologist Dr Phyllis Zee, exposure to daylight in the workplace directly improved workers’ quality of sleep and mood. In regards to the study, Dr Zee says: “There is increasing evidence that exposure to light, during the day – particularly in the morning – is beneficial to your health via its effects on mood, alertness and metabolism.”

The study compared sleep and quality of life among workers in windowless offices and those in workplaces with increased light exposure from windows. As written in the Northwestern Medicine journal, results showed that, “Employees with high exposure to light tended to sleep longer and register more physical activity and better quality of life than their peers in dark offices. Workers in offices without windows reported poor quality of life on measures related to physical problems, vitality and sleep disturbances.”

Exposure to light within the first hour of waking up is essential to harnessing those feel-good effects. Even a thirty minute walk in the morning could be enough to alter our brain chemicals and impact our moods for the better. Otherwise, light boxes are an effective alternative to natural daylight, mimicking the light to trigger the same brain chemicals and alleviate symptoms. Keeping one at your desk or beside your bed can be a great way to give yourself a boost when the sun is tucked away for the afternoon. 

Additional ways to find relief from SAD include talk therapy and, should a professional healthcare provider recommend it, medication. Like with MDD, speaking to someone about those difficult emotions can offer comfort and peace when it feels like nothing else will. 

See, it’s not just flowers and plants that need sunlight to survive. Whenever I feel the sun on my face now, I think of myself as a little green plant, photosynthesising all that glorious light into energy, into serotonin, into wellbeing.