For the two to 10 per cent of the UK population who fear their seasonal affective disorder (SAD) will soon render them bedridden recluses, the first autumnal chill bears a distinct air of malice. But how can you tell if your dampened spirits are simply the winter blues or the beginnings of SAD? And what steps can be taken to mitigate the worst effects of either?

“Lots of us are affected by changes in the seasons,” says Mr Stephen Buckley, head of information at the mental health charity Mind. “We might feel more cheerful and energetic when the sun is shining and the days are longer, and eat or sleep more in the winter. But for those with SAD, a type of depression that is experienced more at particular times of year, these changes have a much greater effect on mood and energy levels and can lead to symptoms that have a major impact on day-to-day life.”

Psychiatrist and spokesperson for the Royal College of Psychiatrists Dr Mark Salter underscores the need for caution around medicalising seasonal shifts in mood and behaviour. “We live in a world that’s becoming increasingly psychologised,” he says. “Just because you’re unhappy, it doesn't mean you’ve got a mental illness. A lot of science is quick to leap to conclusions that SAD is a variant of hibernation, but actually you’ll see a lot of people who hibernate, who withdraw and lead quieter lives in winter, but they don’t get depressed.”

How does he ascertain if someone is suffering from SAD? “In a nutshell, you’re not looking for sadness, but for a steady diminution in pleasure,” he says. “A mood that is persistently low in an all-pervasive, cloud-like fogging way; for a change in [bodily] appetites, with an increased preference for sleep that encroaches into the day, [hunger] for carbohydrates and a decline in interest in sex and relationships and then, behaviourally, a marked withdrawal from the world.”

Those with SAD, or who suspect they might have it, should see a GP right away, rather than trying to battle through solo. “Although self-care is important and can be helpful, if the symptoms of any mental health problem last more than a few weeks, or they affect your daily life, it’s important to ask for help,” says Mr Buckley.

There have been significant advances in treatment in recent years, including SAD-attuned cognitive behavioural therapy (CBT), which “takes into account the patient’s beliefs, their diurnal change, the assumptions they have about themselves and their coping behaviours”, says Dr Salter. “You’ll set simple behavioural goals, for example to get someone to retire to bed a little earlier, even when not sleepy, and to use a relaxation or meditation technique or to exercise first thing in the morning. We know that exercise as a sub-component of SAD-CBT can seem to be effective, especially when combined with light exposure.”

Mind also suggests that getting out and about in daylight can be beneficial for those with SAD, and this advice parlays to anyone who’s feeling blue, too. “It can help to spend time in natural light, for example going for walks, to parks or gardens, or simply sitting near a window,” says Mr Buckley. “Research shows that physical activity can be as effective as antidepressants in treating mild to moderate depression. Going on holiday somewhere sunnier can sometimes be beneficial, although it’s possible you might find things more difficult on your return because of the sudden contrast.”

Given the inclement weather, should people with SAD or a general winter gloom invest in a light box or dawn-simulating device? “Some people find it helps to use a light box – a device that gives off strong white or blue light – or a lamp,” says Dr Salter. “Others might find it useful to use an alarm clock that simulates dawn. However, there isn’t much reliable evidence about this and light boxes can be expensive.”

It’s a common misconception that SAD is caused by a drop in vitamin D. This has been repeatedly disproven, yet most of the population will suffer from a dearth of this vital vitamin as daylight dwindles from October to March, which will have a detrimental effect on wellbeing. “Everyone’s got a vitamin D deficiency,” says Dr Salter. “And anyone who’s vitamin D-deficient feels awful and lethargic.”

But before you start guzzling pills or spritzing a vitamin D (or any) supplement down your throat, it’s wise to have your levels checked. Ms Alice Mackintosh, a nutritional therapist and co-author of The Happy Kitchen: Good Mood Food, says: “The government suggest all adults should consider a daily supplement of 10 micrograms (or 400iu) vitamin D between October and mid-March, but it’s also a good idea to speak to an expert about what might be the optimum dose for your body. You can go to your doctor to test, but there are also home test kits.” Should you begin supplementing, go for D3.

Ms Mackintosh also suggests that for most people, a balanced and widely varied whole food diet that includes complex carbohydrates, a little healthy fat, plenty of vegetables and some fruit, and protein at regular meal times is a good idea. “There is a tendency in winter to rely on sugar, caffeine and quick energy foods, but ultimately, with SAD there can be a sluggishness, lack of energy and zest for life. It shouldn’t be about eating foods that are going to sap you further and leave your blood sugar on a rollercoaster. Protein at meals is a great way to make sure energy levels stay stable – so, though a bowl of porridge at breakfast is great because it’s a wholegrain carb, actually there’s very little protein. Whereas if you add nuts and seeds, your energy levels will be steadier over the day.”

It’s also a bright idea to get as many colours onto one’s plate as possible. Not only does it make for an uplifting aesthetic, but also increases “the chance that you're getting an array of vitamins, minerals, antioxidants and other important nutrients,” Ms Mackintosh adds. “A rainbow of fruit and vegetables is therefore good at any time of the year. We’ve previously used the acronym ‘cut The CRAP’ (carbonated drinks, refined sugars, additives and preservatives).”

Ms Mackintosh also recommends that everyone works to get zinc-rich foods at this time of year to boost their brain and immune system. She suggests we tuck in to poultry, fish, seafood, pumpkin seeds, sunflower seeds, hemp seeds and oats. On top of this, she feels it’s prudent to secure an abundance of anti-inflammatory omega-3. Oily fish is often cited as the prime source of omega-3, but for vegans or those who don’t like it, it’s easy to seek out plant-based sources such as linseeds, walnuts and flax seeds. And raw cacao is a further inflammation-fighting, brain-function-boosting food.

As for tryptophan, which is often touted as the foundation of a SAD-geared diet because it’s a precursor for the happy hormone serotonin, Ms Mackintosh remains skeptical. “There isn't much research that eating tryptophan equals more serotonin in the brain. Still, it’s a good idea to eat tryptophan-rich foods such as walnuts, dairy products and bananas because they’re nutritious.”

Ms Mackintosh believes that keeping our second brain – our gut and its countless bacterial inhabitants – happy via fibre, probiotic and prebiotic foods is a good way to support mental wellbeing. “Our digestive system and brain are inextricably linked,” she says. “There’s a nerve that links them called the vagus nerve, and a lot of our nervous system is found within our gut, known as the enteric nervous system. Eighty per cent of our serotonin is found in the gut and – although more research is needed in this area – it’s been shown that bacterial balance may affect mood, even to the point where people with anxiety have been given probiotics and then suffered less. Over winter, as we’re exposed to more colds and flus, our gut-microbial barrier can be impacted, so it’s a good idea to maintain a diverse diet that features fibre, plant-based foods and microbe-dense pickles and ferments. They can feed different bacteria, help protect your immune system and potentially also support your brain.”

And there you have it, from exercising in daylight, daylight-aping lamps and seeking professional assistance to dietary guidance, the sharpest advice around on surviving and, dare we hope, even thriving through to spring 2020.

Disclaimer:  Always speak to a doctor before making changes to your lifestyle, including diet and exercise or medication

For further information on seasonal affective disorder, visit the Mind website

**CALM (Campaign Against Living Miserably) offers listening services, information and support for men who feel down or are in crisis. **

Visit thecalmzone.net or call 0800 58 58 58 (5.00pm to midnight)

The Samaritans offers a free 24-hour helpline. Call 116 123