As Christmas approaches, many people will be experiencing a mixture of excitement and trepidation. But for many sufferers of social anxiety, this can be the most traumatic time of the year, writes Olly Ricketts.

It is estimated that social anxiety disorder affects up to 10% of the UK's population.

The first clinical guideline on the subject, published by the National Institute for Health and Care Excellence (NICE) in May, defines the disorder as the "persistent fear of or anxiety about one or more social or performance situations that is out of proportion to the actual threat posed by the situation".

The festive period provides a unique combination of such situations. While a degree of worry about finances, potential drunken mistakes and the awkwardness of spending time with extended family is entirely rational, sufferers of social anxiety can obsess about such issues until they prove debilitating.

Why is Christmas stressful? Increased pressure to spend time with others

An expectation this is a happy time of year - pressure to make the most out of an event and for everyone to have a good time

Mixing with people you have not necessarily chosen to spend time with

Sense of loss - whether because of not having a social group, or being out of work

Constant reminders of how we should be enjoying ourselves at Christmas on TV, in advertisements and even in supermarkets Source: Laura McMurray, Senior Psychological Therapist, iCope When does mental health become a problem?

Physical symptoms include blushing, excessive sweating and shortness of breath, but the most incapacitating effects are caused by sufferers' fixation on their perceived social inadequacies. Potentially stressful events consume thoughts for months beforehand, and the often imagined disaster is analysed at great length afterwards.

A perceived threat can be triggered by anything from meeting new people to being watched while eating.

Christmas poses particular issues. Most obvious are the myriad social engagements and their often alcohol-fuelled nature, though there are other more surprising worries to face. Heather, 38, begins to worry about Christmas as early as September.

"I'd finished most of my own [Christmas] shopping in October because I started early to avoid crowds," she explains.

Heather's anxiety increases as Christmas approaches. A particular worry is the office party.

"Most years, I buy a ticket for the work do. I actually buy the ticket, knowing full well I won't go. I buy [it] to make sure people don't think I'm tight-fisted, or that I hate Christmas, or that I don't like their company."

Heather's constant fear that she will not live up to expectations even extends to buying presents for colleagues.

"For Secret Santa, I've spent three times the agreed budget on a gift to make sure it'll be accepted by the person. I feel sick at the thought of them publicly rejecting what I buy and everyone knowing I was the one who bought the inferior gift."

The triggers which cause social anxiety are so varied that it is difficult to describe a "typical" sufferer, either in terms of symptoms or personality. Although social anxiety can often develop early in life (NICE claims the "median age of onset" is 13), and many recover before adulthood, it can emerge at any age.

According to Dr Gillian Butler, consultant clinical psychologist and author of Overcoming Social Anxiety and Shyness, it is also "one of the only anxiety disorders to affect both men and women equally".

Even people that appear confident and extroverted can have the disorder. Social anxiety recently made headlines when actress Jennifer Lawrence spoke candidly about her battle with it.

The unpredictable and varied ways anxiety manifests itself means that while some, like Heather, will actively avoid events such as the office Christmas party, others' anxiety is fixated on the fear that they would be talked about if they did not go, and so they attend in spite of how uncomfortable they feel in such situations.

There are even people like 20-year-old university student Alex, who has experienced "paranoia, low self-esteem and lack of confidence" for 10 years, yet genuinely looks forward to the festive season, speaking excitedly about the "special atmosphere and general increase in the happiness of others" at this time of year.

Alex's social anxiety decreases when he is around his family. However, according to Butler, for some being around loved ones at Christmas can itself provide a trigger for anxiety.

"People can suffer with social anxiety in the family unit. You may as an older person feel a real fool talking to the children. It can bring back memories of adolescence and embarrassing times in the past," she explains.

People can suffer with social anxiety in the family unit Gillian Butler

Butler advocates cognitive behavioural therapy (CBT) to treat social anxiety disorder. CBT is based on the premise that symptoms are tackled, rather than the underlying causes of anxiety, and that if a person's negative thoughts regarding their perceived social inadequacy can be changed, in time their behaviour will change and their anxiety will reduce.

Although there are other treatments available, such as drugs, CBT is the most commonly prescribed method used to combat the disorder.

It is not without its critics, however. The therapy is typically prescribed in 11-week blocks, which some feel is too brief to make a lasting impact.

Chartered clinical psychologist Dr Oliver James believes that any benefits related to CBT are temporary, and effective treatment should deal with the causes as well as the symptoms of anxiety.

"It [CBT] encourages people to tell themselves a story about their anxiety and makes no attempt at all to understand the causes," he claims.

More from Ouch On Ouch talk show 103, Charlotte Walker - a recent winner of a VMG Mind Media Award for her blog on life with bipolar - joins autism campaigner Kevin Healy to talk about why their impairments can make Christmas a difficult time of year. Ouch talk show 103: Bah humbug

As many sufferers find speaking to an authority figure such as a doctor impossible, online treatments have become increasingly popular. As well as online CBT courses, internet forums can provide solace.

Alex and Heather are both members of SAUK, an internet forum for the socially anxious, which has amassed over 15,000 members (and regularly sees an influx of members over the festive period) since it launched in 2000.

Louisa Hatton, an administrator on the site, believes that SAUK provides a much needed sense of community.

"Because part of social anxiety is trying to avoid others seeing your fears, it can be refreshing to interact with other people who understand those worries and can empathise. It [SAUK] also empowers people to take a lead in their own recovery by giving them access to information and the experiences of others."

Louisa is proof that social anxiety can be conquered, having transformed herself from being "essentially housebound to almost social anxiety-free". Her advice to those that are feeling distressed in the run-up to Christmas is simple.

"Firstly, remember that although social anxiety is often isolating, you're absolutely not alone.

"Secondly, be proactive. Even simply looking into what social anxiety is can be a great first step towards taking control of your worries and fears."

Follow @BBCNewsMagazine on Twitter and on Facebook