When it comes to autism, awareness of the condition and its effects on a person's behaviour has risen dramatically in recent decades.

However on April 2, World Autism Awareness Day, campaigners will still be working hard to address misconceptions about a condition that affects more than half a million people in the UK.

Since November last year, The National Autistic Society has been campaigning to dispel myths (such as the ideas that autism only affects children or that all people with the condition are geniuses), via a social media campaigns -- see tweets below.

A key message of their awareness-raising mission has been about diagnosis, as research suggests that most adults with the condition are unaware of it.

A survey conducted in England by the University of Leicester in 2011 found that not a single person identified with autism or asperger’s syndrome actually knew they had the condition.

What are the most commons signs of autism in adults? Find out below..

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  • Difficulty With Social Communication

    <a href="http://www.nhs.uk/Livewell/Autism/Pages/Diagnosisinadults.aspx" target="_blank">According to the NHS</a>: "People with autism have difficulty using and understanding verbal and non-verbal language, such as gestures, facial expressions and tone of voice, as well as jokes and sarcasm. "Some people with autism might not speak or have fairly limited speech. They may understand what people say to them but prefer to use alternative forms of communication, such as sign language."

  • Difficulty With Social Interaction

    "People with autism have difficulty recognising and understanding people’s feelings and managing their own feelings. "They may, for example, stand too close to another person, prefer to be alone, behave inappropriately and may not seek comfort from another person. This can make it hard for them to make friends," says the NHS website.

  • Difficulty With Social Imagination

    According to the NHS: "People with autism have difficulty understanding and predicting other people’s intentions and behaviour and imagining situations that are outside their own routine. "This can mean they carry out a narrow, repetitive range of activities. A lack of social imagination should not be confused with lack of imagination. Many people with autism are very creative."

The research also revealed that autism appears to be commoner in males, those without higher educational qualifications, and among individuals living in social (government financed) housing.

In a blog recently published on The Huffington Post, Hannah Gal reveals one young male student's struggle with autism.

"There was also a time when while standing on a platform waiting for a train, an announcement instructed passengers to stay behind the yellow line. I just couldn't figure out how I am meant to get on the train with the yellow line still there."

"Teachers may have found it more difficult due to my literal thinking. For example if they asked me to 'pull my socks up', I would have literally done just that, without meaning to be cheeky or insolent."

To find out more about autism and World Autism Day visit The National Autistic Society website or follow them on Facebook here.ware

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  • Davis Autism

    RT @Autism: #AutismFact: The UN declared 2 April as World Autism Awareness Day (WAAD) in 2008 http://t.co/FJ7APGGTbX

  • Julia

    RT @Autism: #AutismFact: Far too many children with autism do not get the education they need and deserve http://t.co/ppsSEzvFaA

  • sophie

    RT @Cars4Autism: #AutismFact: 43% of young people with autism surveyed in 2011 felt teachers didnt know enough about the condition http://t.co/nDx5i8Rqr4

  • Mari Nosal

    RT @Autism: #AutismFact: The Autism Research Centre was founded in 1999, bringing together scientists from @Cambridge_Uni http://t.co/rM6ObRZNcF

  • ABA Network

    #AutismFact: With the right help and support a person with autism can make progress and reach their potential http://t.co/N0tKL1J9Vn

  • Jo Worgan

    RT @Autism: #AutismFact: The adult autism strategy is the Government plan to ensure that adults w/ autism get the help they need http://t.co/BI2h23bBsF

  • NHS Eastern Cheshire

    Recent diagnosis rates suggest four times as many boys as girls have autism #AutismFact http://t.co/pBbgsni1Zm @AmbitiousAutism

  • Brian O'Rourke

    RT @Autism: #AutismFact: Autism is a hidden disability http://t.co/TDn7m2bnFN

  • Libby

    #AutismFact Autism receives less than 5% of the research funding of many less prevalent childhood diseases

  • Libby

    #AutismFact Boys are nearly five times more likely than girls to have autism

  • Nat Autistic Society

    #AutismFact: Autism is a hidden disability http://t.co/TDn7m2bnFN

  • Libby

    #AutismFact Autism prevalence figures are growing

  • Libby

    #AutismFact Autism now affects 1 in 88 children and 1 in 54 boys