The end of October signals a "pre-clock changing doom" for Catherine - and she is not alone.

The 34-year-old engineering worker from Glasgow is among the 160,000 Scots estimated to suffer acute symptoms caused by seasonal affective disorder (SAD), a form of depression triggered by a lack of exposure to sunlight during the short, dark winter days.

Around 9% of Scots are believed to experience SAD to some degree, but for Catherine the condition has been associated for more than a decade with a debilitating annual bout of "sofa wallowing".

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She said: "Even at the weekends, the prospect of getting up and going for a walk - you know it's good for you, but you just cannot get off the sofa. That's how it is for me.

"It becomes this negative feedback loop where you just make yourself feel worse and worse as the winter goes on and you tip into this downward spiral. I notice that I drink more alcohol in the winter, which makes everything worse of course.

"Then there's the anxiety that comes from doing anything. I catastrophise so that just going to the supermarket becomes this crazy anxiety-inducing thing, which it shouldn't be.

"I'm hyper aware of the clocks changing and then it starting - it's a fairly rapid decline into SAD."

For the first time in years, however, Catherine is feeling more optimistic.

She is one of around 20 people who took part in a trial of 'Wintering Well' workshops last year for a research project led by two professors of human and cultural geography - Hester Parr, of Glasgow University, and Hayden Lorimer, of Edinburgh University.

The goal was to empower SAD patients with more effective coping strategies through creative exercises, cognitive behavioural techniques, and support groups.

The findings have now been translated into a free online "toolkit" which will be launched on October 28.

Professor Parr, who is originally from England, said she "profoundly noticed" noticed a deterioration in her own mental wellbeing during winter when she first moved to Scotland, with the change worsening again when she moved from Dundee to Glasgow.

"The difference between east and west is quite significant," she said.

"From a personal point of view I understood a little about what that condition might feel like, but obviously people with a diagnosed disorder are much more profoundly affected.

"Most people don't like the dark, wet periods, but this is an exaggerated response - a more severe response.

"People feel very lethargic, they find it very difficult to fulfil the normal functions that they do all through the year. They become less social, more withdrawn, more irritable.

"There's a sense of shame. People feel that they can't really speak about their experience because there's that cultural judgement of 'well, everybody feels like that'.

"But for people with SAD it's more deeply felt, more deeply debilitating, so what we've tried to do is create a new conversation around this experience so that people feel they can admit and acknowledge the condition.

"That's one of the most valuable things that the people who took part in our workshop talked about - the ability to meet other people and be able to talk about it."

The Herald: Prof Parr said people experiencing SAD symptoms often felt a 'sense of shame' and 'cultural judgement'Prof Parr said people experiencing SAD symptoms often felt a 'sense of shame' and 'cultural judgement' (Image: Gordon Terris/Herald&Times)

Over the course of six-months, participants met up every three weeks for group activities.

They were also guided on techniques to maximise their exposure to natural light - from daily walks to rearranging their home interiors - and on strategies, such as mindfulness, to change their "psychological relationship" with winter.

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In one 'sky-framing' exercise, participants were asked to "look again" at an apparently overcast sky through a picture frame and describe in detail what they saw.

"Of course the sky isn't uniformly grey - it's a real patchwork of different tones, and colours and lights," said Prof Parr.

"That one, small, creative task was really meaningful for a lot of people."

Prevalence of SAD appears to be roughly 50% higher in Scotland than the UK average, but it is less clear how Scotland compares against other countries at the same latitude as colder climates in the likes of Canada and Sweden are more prone to snowy, brighter, winters.

Prof Lorimer said winter light festivals were welcome, but more could be done to improve lighting in residential neighbourhoods in general.

He said: "There's a lot of initiatives at the moment to think about how to make towns and cities more habitable places.

"Some of that's about the physical fabric, but sometimes it can be more creative things about what you do with light.

"Light is absolutely essential to us, so how can you create pleasantly illuminated spaces?"

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He added that he hopes that the SAD toolkit will help other people living with the condition to "think practically and get a bit of a structured plan as to what you need to put together a wintering well group".

For Catherine, she is heading into winter this year feeling able to "engage a bit more with the outdoors" and take pleasure from "noticing" changes in the environment.

Her key takeaway, however, was the "solidarity" and "spikes in happiness" that came from the group's regular meet-ups - which they are continuing now on an informal basis.

She said: "There's something so powerful to be in what is essentially a support group. I would say that that is what we became.

"It's hard when you're older to make friends, it's hard to make the time, it's hard to get out there, but if you can it really does help."

Free tickets for 'Wintering Well: Living with Seasonal Affective Disorder' are available here. The event, to discuss the findings of the Living with SAD research project and launch free resources to help with winter depression will be held at Glasgow University on October 28