Mrs Smith, of Epping, originally assumed it was just shyness but once he started pre-school she realised it was more serious.

''When he was younger, I thought it was normal and age-appropriate that he wasn't talking to adults,'' she said. ''As he got older, I realised that compared with other kids, he was really shy towards adults. It got to a point where he wouldn't even talk to other family members, like grandparents and aunts and uncles. He started preschool and the staff told me that he would rather miss out on things than ask an adult. At lunch time, if there weren't enough chairs to sit on, he wouldn't eat lunch rather than have to ask a teacher for a chair. He would rather go hungry than have to talk to an adult. That's when I started to really worry.''

Last year Mrs Smith joined a long-running research project into childhood anxiety at Macquarie University's Centre for Emotional Health. Through the program, she learned that Tyler suffered from both shyness and anxiety. After 12 months of strategies, including cognitive behavioural therapy that exposes him to the social situations that can cause him anxiety, Mrs Smith is pleased with his progress.

Associate Professor Jennifer Hudson, from the centre, said clinical anxiety was the most common mental health problem in preschoolers, with up to 10 per cent affected. She welcomes the July 1 introduction of widespread mental health assessment for preschoolers, saying: ''Anxiety in the preschool years is most likely to predict anxiety in adolescence and adulthood. We know that if we target it early in life, we can treat it and prevent other mental health problems from developing later in the child's life.''

Mrs Smith agrees. ''If I had been able to take Tyler to the GP to have an assessment at the age of three, it would have highlighted that there was a problem and it was something that needed to be addressed.'' When her daughter, 23-month-old Harlee, turns three she will be happy to have her emotional health assessed.