Natalie Wiles always struggled to concentrate. When she was diagnosed with adult ADHD, a lifetime of problems fell into place. Sophie Goodchild reports

Natalie Wiles still remembers how she just "ground to a halt" in the second year of her degree at Central Saint Martins College of Art and Design. Faced with her dissertation, Natalie, then 23, found herself struggling even to "string sentences together". The result was a gradual descent into depression and anxiety. "The subject (of the dissertation) was 'The Colour Blue', but I couldn't even sit down long enough to concentrate. The smallest distraction completely took away my focus – I felt angry, frustrated and panicky. So I painted a very large picture, all sky blue with a tiny beach-ball in the right-hand corner, just to show how I felt."

Eventually, her GP diagnosed attention deficit hyperactivity disorder (ADHD), a label more associated with disruptive children than disorganised adults. Now a successful garden designer, Natalie, 39, is among an estimated one in 10 adults who displays classic ADHD symptoms such as impulsive behaviour, excessive procrastination, and an inability to complete everyday chores. This is not simply a case of failing to finish the tasks on your "to do" list. Adult ADHD sufferers cannot even focus long enough to write such a list.

Referrals to the Maudsley Hospital in London for adult ADHD have nearly doubled in two years from 39 to 79 patients. New guidance from the National Institute for Health and Clinical Excellence (Nice) was a factor as well, and a major step forward in the official recognition of adult ADHD. Yet Professor Philip Asherson, an honorary consultant psychiatrist at the Maudsley, reveals there are thousands of "forgotten" sufferers whose condition has been overlooked or incorrectly attributed to depression or anxiety. They end up on medication which has very little impact on their condition. The prospects for these patients are bleak: broken relationships, career meltdown and exceedingly low self-esteem.

"Almost no one was diagnosed before the mid-Nineties, so if you were a child a decade or 15 years ago, then you would have been overlooked," Professor Asherson says. "Even now, we know that children aren't diagnosed when they should be. What brings a child to a psychologist is bad behaviour, not an inability to concentrate."

Studies have linked ADHD with low intelligence. But Dr Asherson says ADHD patients come from a range of backgrounds and with high to low IQs. One of his current patients is a graduate with a first-class honours degree who failed to stick at any of his 25 jobs. "His inability to focus on anything and complete lack of organisation left him clearly distressed. You get people from low intelligence to very bright. The clever ones develop strategies to manage their symptoms. Some, though, are only able to focus when they find something which completely grabs their attention."

Therapist Andrew Lewis counts airline pilots, company directors and university dons among his "clients". Diagnosed with ADHD in his forties, Lewis now runs his own "training" service ( for adults with the condition. He works with clients to develop individual strategies such as "buddying", where patients link up with a friend to motivate them. "The upside to ADHD is people can be really creative and non-conformist," he says. "I suspect the suffragettes had the condition. But there are huge waiting lists for NHS treatment, and this can result in broken relationships and families. People end up travelling to Scotland because the NHS is failing them."

The Maudsley is one of only two in-hospital adult ADHD clinics in the UK. It is still the only clinic that accepts referrals from across Britain, though local services are slowly improving. There is no "cure" for ADHD. Scientists believe it is caused by a lack of dopamine, the mood-regulating brain chemical, so clinicians prescribe drugs such as Ritalin to stimulate dopamine release.

A new treatment, though, is being pioneered at the Maudsley alongside drug therapies. Talking therapies such as cognitive behavioural therapy (CBT) are used to help patients to take control of their disordered lives. Natalie is one patient who has benefited from CBT, a treatment she describes as "life-saving".

At school, the mother-of-two, who also suffers from dyslexia, was always "the kid with the desk outside in the corridor. I wasn't bad, just my brain would get overloaded". Social situations were also a challenge for Natalie, which made life very lonely. "People didn't take me very seriously – I felt like the odd one out," she explains. "I'd say things that were really blunt and random, like David Brent. I found it really difficult to follow conversations. I love the idea of a long conversation with someone, but I would always lose the context. It's only since being on the medication that I've realised how difficult it was."

She would also get overly involved with people who had overwhelming problems. These relationship "pickles" ended with a traumatic row in one case. "'I was friends with someone from college who was homeless at one stage with a baby and I took her in," she says. "Anyone else would have run a mile. I didn't set boundaries, though, so we ended up having this big fight."

Her problems really began at Saint Martins, when she enrolled on a sculpture degree course after a succession of bar jobs. At first, Natalie thought she had depression, and her GP prescribed Prozac. But he said she was also displaying symptoms of ADHD. The pills helped to lift Natalie's mood for a time. Then she became pregnant with her first child and had to come off medication. Although she loved being a mother, the daily routine of looking after a demanding baby, and then a second, proved too much. Even simple tasks such as switching on the washing machine were too difficult for Natalie's disordered brain to cope with.

"I struggled when my children were three and one year old," she says. "I would cook food for the little one... then, while I was looking after both of them, I'd forget what I'd done and make another dinner. And making sure I stayed in for the health visitor, it was just impossible. I hated letting people down, but she would knock and I'd never be in because I'd forget. I was completely disorganised, with no concept of time. I'd forget kids' parties. The house was full of clutter – I'd wade through clothes just to get to bed and spend the day in a state of panic. Children need routine, but I would panic trying to write a list. It was like the children had two mums because my husband did everything. It was just chaos."

Her husband, Mark, 46, has always been supportive, but Natalie was depressed, exhausted and in desperate need of help. Her GP sent her to a psychologist, who in turn referred her to the Maudsley's ADHD clinic. Here she was offered medication and 16 sessions of CBT. At first, she did not take the CBT, because "I still thought I could deal with my problems".

Natalie, who lives in St Albans, eventually started CBT in her second year of therapy. The sessions were spread over the course of 12 months, which enabled her to confront situations as they arose. Each session started with an agenda, and Natalie was taught to challenge her thoughts.

Natalie finished her course of treatment 10 months ago and has now set up her own garden design company. Her husband helps with the books and everything is organised with the help of her diary. Therapy was not a cure, she says, but has helped her to regain control of her life. She still takes medication, which is "like a splint", though one day she would like to come off it. "I needed to get myself sorted for the kids [now nine and 11]," she says. "I went in with a lot of assumptions, but I found it quite easy to resolve many of my issues, even though I'd been living with certain mindsets for so long."

Even when Natalie has "a million things to do", the CBT has taught her to put these things into boxes and do them one at a time. "Strangely, I had no idea that being organised was the secret of my success," she says. "It seems so obvious, but in the past, this kind of thing slipped away so easily. If I feel stressed, I can now see what to do right in front of me."

With obvious pride, Natalie says she is now "more successful than I thought possible". Her ambition is to create a show garden at the Hampton Court Palace Flower Show this year. "I'd encourage anyone to try therapy," she says. "The really horrible feeling was not having control. My despair was about not seeing a way to move out of the cycle I was in... but it can be done."