Laura James had always felt different, but didn't discover why until she was in her 40s

'I am not mad, bad or sad. My experience of the world is at odds with how most people see it,' says Laura James.

For 45 years Laura knew she was different but didn't know why. Then she was diagnosed with autism.

Suddenly things made sense. 'In my mind, I played episodes from my childhood, my teens and my later life as a mother of four, aware for the first time how my autism explained so much,' said Laura. 'They flashed into my consciousness as individual moments. Standing away from the group of girls giggling in the playground. Sitting in tears in an exam room, unable even to write my name on the paper. Walking past bars watching a group of women on a night out and wondering what it felt like. Staring at a plate of food, knowing that because the burger bun was wet from mayonnaise, I could no more eat it than I could run a marathon. Sitting in an office being so distracted by the buzzing of an overhead strip light that I didn't notice the phone ringing on my desk. Spending an entire Saturday researching a special interest only to realise it was 7pm and I was still in my pyjamas and hadn't eaten. With each scene came a feeling of context and understanding.'

The diagnosis came almost by mistake. She had just discovered she had Ehlers-Danlos syndrome, a connective tissue disorder with symptoms including digestive problems and limbs which dislocate easily. 'While I was in hospital having tests for it, a nurse presumed I was autistic due to my behaviour and the fact that autism and EDS are often found together,' said Laura. 'At first it didn't seem possible, but the more I researched autism the more it became clear that it described me perfectly.'

Her GP referred her to a psychiatrist for an assessment - and diagnosis.

So how did friends and family react? 'Everyone has been really interested and supportive – once the initial shock wore off!' said Laura. 'Having been endlessly misdiagnosed with everything from generalised anxiety to (and this is my personal favourite) 'bad luck,' I guess I had just given up trying to find an answer.

'The biggest change is that I now understand myself. It has allowed me to make sense of why I think, feel and behave the way I do. It has also allowed me to meet many other autistic women, which has been a really powerful experience for me.'

Far fewer women than men are diagnosed and Laura said: 'I think most of us have quite a stereotypical idea of what autism is and I don't fit that at all. When most people think of autism they imagine a geeky guy who works in IT, not a woman who loves fashion and books.'

She believes many autistic women mask their traits in an attempt to fit in. Her coping mechanisms include writing lists, setting alarms and making time to be alone.

Laura runs a communications agency, has four grown-up children and lives with her photographer husband, Tim, in Norwich's golden triangle. She has previously written cookery, psychology and lifestyle books. Now her memoir, Odd Girl Out, is published in paperback.

It is an account of the year following her diagnosis and the hardback edition had a hugely positive response from readers and reviewers. 'I still get messages every day from women who believe they are autistic, have EDS or both, and from the parents of girls with autism,' said Laura.

'The diagnosis came as a vindication. All my life I had tried so hard to be neurotypical, but in that one moment it became utterly clear that it was never going to happen. I was never going to fit that mould. I had stepped out of the psychiatrist's consulting room into a new reality. The colours around me seemed brighter, the noises sharper. Finally I had the answer I had been searching for all my life.'

Odd Girl Out by Laura James is published by Bluebird for £16.99.

On Saturday, May 26, Laura James will join poet and novelist Joanne Limburg, author of The Autistic Alice, and writer and academic James McGrath, to discuss the reality and misconceptions of living and writing with autism. Autism Writes Back! is part of the City of Literature Weekend at the Norfolk and Norwich Festival, in Chapelfield Gardens. Tickets £8. nnfestival.org.uk