While the dark days of New Zealand’s winters don’t hold a candle to Antarctica’s, there’s no doubt they can still affect our physical and mental health. So what can we learn from the experts – people who spend six months of the year in darkness?

This story was first published on Stuff. Listen to the podcast version here.

It’s 9am in Antarctica and Greg Kukutai has taken his laptop outside into absolute darkness.

In -45C conditions, the winter leader of Scott Base pans the camera about to show, well, not much. The lights of the base are blazing but everything else is black.

Back inside, base engineer Steve “Sooty” Denby describes how a group gathered on the ice in April to watch as the sun dipped below the horizon.

“It’s pretty amazing to watch the sun set and know that’s it for another six months.”

While the dark days of New Zealand’s winters don’t hold a candle to Antarctica’s, there’s no doubt they can still affect our physical and mental health.

Time and again it’s been proven that when light dies sadness will rise and, while feelings of melancholy commonly accompany the change in season, experts are warning this year’s slump might feel even worse.

That’s because with much of New Zealand’s last summer missing in action, so too are the myriad essential health benefits the sun provides – things like vitamin D, mood-boosting serotonin and an all-round improvement in mental wellbeing.

Combine this deficit with three years of pandemic-induced upheaval, the continuing cost of living crisis and a country already struggling with mental health, and we’re sitting ducks for a national downer.

Niwa climate scientist Gregor Macara stops short of labelling last summer as the worst ever, though admits it’s hard to think of one worse. “For Auckland and Hawke’s Bay it’d be hard to beat how bad it was – pretty dour and depressing.”

But just as record rainfall drenched and damaged those regions, others were simply robbed of the sun and its benefits.

By the end of May, Auckland’s north had only seen 64% of its usual sunshine, losing 333 hours worth. Wairarapa lost 286 and Northland was cheated of 195. Meanwhile, the West Coast saw more than 100 extra sunny hours and Central Otago scored at least 200 more than usual.

“Gee, I wish we could have shared them,” says the latter’s mayor Tim Cadogan, “it was a wonderful summer except for a sense of guilt about our friends in the North Island.”

Down in Antarctica, Denby is in his fourth winter of complete darkness. A team of abut 18 staff run the base during its six-month winter – almost half have worked in the defence force.

”They sort of screen you before you come down – to see if you can handle it…some don’t.”

Denby says he’s pretty used to it now but admits to a creeping melancholy that can take hold once the sun goes. He also experiences T3 syndrome, a condition found in polar explorers and caused by a decrease in levels of the thyroid hormone. Its effects include forgetfulness, cognitive impairment and mood disturbances.

“I can walk from one end of the base to the other and when I get there think “what am I doing here?”. I have to carry a notebook…it’s not as disastrous as it sounds, it’s quite funny.”

Back in NZ, when summer literally went south, Kiwis took flight. In the week beginning May 8, when torrential rain caused havoc in Auckland, Flight Centre saw bookings to Eastern Europe’s coming summer rise by 70%.

In recent weeks, the travel agency has also seen bookings to Latin America and the Caribbean rise by more than 30%, and to northern Africa by 28%.

But for those of us who can’t afford to follow the sun, experts say we can at least bring the sun to us.

Dr Alan Rosenthal and his light box are beaming in from Washington on Thursday, 40 years after he first described seasonal affective disorder – or Sad – a type of depression related to the changes in seasons.

Marked by symptoms including fatigue, depression, hopelessness and social withdrawal, Sad is estimated to affect from about 1% to 10% of the global population with women more commonly affected than men.

Back in 1976, Rosenthal found that when he moved from his native South Africa to the US both his and his wife’s moods and energy levels slumped during the country’s colder winters – when the weather got better, so did they.

Then, at a party a few years later, he met scientist Alfred Lewy who’d been researching the sleep hormone melatonin and how light affects mood. The pair got talking, studies started and, ultimately, a syndrome was born.

Sad was formally recognised by the American Psychiatric Association in 1987 but Rosenthal says it’s always been a thing; we just didn’t have a name for it.

Yes, he says, everyone tends to get a bit glum in winter, but seasonality – or how we respond to the seasons – comes on a spectrum.

“Some people won’t know what you’re talking about, other people will feel bleh and others will feel really under the weather. It’s a matter of degree.”

Rosenthal recommends a range of tactics for combating Sad though being prepared for its onset is the single most important. Cognitive behavioural therapy has also been shown to work, as has meditation, a healthy diet and, in essence, fake sun.

The sun box currently sitting on his desk is used daily by the psychiatrist as soon as he recognises Sad sneaking up on him. Mimicking outdoor light at about 10 times the intensity, the screens are one of the most popular and effective treatments for Sad: sufferers typically use them for half an hour twice a day.

Rosenthal says studies have shown symptoms of Sad and other depressions can quickly improve with the use of lamps, much faster than antidepressants which can take weeks to work. Even so, he encourages people to embrace whatever help they need: “there’s nothing wrong with medication.”

Eric Bird, technical director of the Scott Base rebuild programme, says it might be fake, and won’t be there for another four years, but sunlight is finally coming for Antarctica’s winter. When new buildings are shipped from New Zealand to the ice in 2027, new technology in the form of tunable LED lights will mimic daylight’s natural ebb and flow when the real thing is nowhere to be seen.

“One of the key issues is seasonal affective disorder and the effect on circadian rhythms…you don’t realise how it impacts you until it does. I’ve been down there a couple of times, but I’m not brave enough to do a winter.”

Anna Wirz-Justice, a New Zealander and emeritus professor at the Psychiatric Hospital of the University of Basel, is a world authority on sleep and depression research, last year adding the prestigious Daylight Research Award to her many other accolades.

She introduced light therapy to Europe as a treatment for Sad and says while the mechanisms are still unknown, it “works extremely fast to improve depressive mood”.

“It is also efficacious in non-seasonal and bipolar depression, often in combination with medication, and in a variety of sleep disorders to stabilise timing. We know that the light information from the retina is transferred via a specific neuronal tract to the biological clock, separate from visual function.”

Recently, a new pathway has been found whereby light information goes directly to regions of the brain involved in mood and sleep regulation.

“The clinical effects are well documented and beginning to be accepted by the medical establishment, and the way light works is beginning to be elucidated,” she says, “but because it can’t be patented there is little effort to carry out the large randomised double-blind placebo controlled clinical trials that would speed up inclusion in treatment guidelines.”

As for Sad’s grip on New Zealand, Wirz-Justice doesn’t know of epidemiological studies investigating the prevalence.

“If we compare our data in Switzerland at 47 °N where 2% of the adult population suffer from SAD and 8% from the ‘winter blues’ then it could be assumed that a similar prevalence could be found at 46°S in Dunedin and less in the North Island.”

Psychologist Marc Wilson says that although Sad is accepted by a majority of the clinical and research community it’s got a kind of twilight existence; apt really, when you think about it.

“It’s not recognised as a disorder in its own right in the Hypochondriac’s Guide to Psychiatric Disorder (the DSM-5), but rather as a sub-type or ‘specifier’ for depression.”

Wilson says there are pros and cons to this, stressing the importance of an appropriate diagnosis to rule out “normal” depression which can also get worse in winter; bipolar or atypical depression.

“The downside is that some research says clinicians may not think of going that route, and therefore may not offer the treatment of first choice.”

When it comes to any sort of winter blues, Wilson says the one thing that is known is that not doing anything won’t help. Even a 30-minute walk has been shown to be as good for your mood as anti-depressants, he says, and a break in routine is often, particularly with experiences that involve other people, also beneficial.

“Unfortunately, all common sense… nobody will go for it.”

That might be the case on the mainland but Antarctica’s winter team know all too well the dangers of doing nothing. As well as just keeping an eye on each other and keeping communication open, the staff take part in organised activities designed to boost their mood.

So far there’s been a high-spirited game of hide and seek, an escape room challenge – undertaken in fancy dress – drives out to watch the stars and auroras, as well as social occasions involving the US staff from nearby McMurdo Station. Those Americans are also soon to be challenged to a game of mini golf, played in the dark.

Games aside, Kukutai says staff still have to be tough and sometimes that means talking about feelings. Sometimes it just means celebrating the little things.

And when the sun finally rises in August, Antarctica’s winter people will do just that, Denby says.

“When you get your first feeling of heat from that sun it’s hard to imagine. You walk around a building, it’s still -30C but you feel it, that warmth is amazing. It’s a revelation.”

Expert’s top tips for beating Sad and making the most of winter

Get outside: preferably for half an hour at the same time every morning. Yes, even if it’s not sunny.

Embrace the ‘snuggliness’ of winter; use the season to rest and recharge.

Break your routine by doing something new or something you haven’t done for a while.

Get therapy: whether its from light, a health professional, or both.

Do something nice for yourself: take a bath, or schedule an hour to read a book. Drop someone a text to say you’re thinking of them.

Bring that outside light in: clear shrubs back from windows; clean the glass; get a skylight if you can.

Know that it’s OK to sometimes feel low but it’s more than OK to ask for help.