SINGAPORE: Up to half of preschoolers have a mental health disorder, with anxiety the most commonly diagnosed issue, according to a new study.

The shock research also reveals more than one in five of the children involved in the study suffered from two or more mental illnesses – known as comorbidities – before they even started school.

The findings have sparked calls for preschoolers to have their mental health screened when they are assessed by GPs and maternal health nurses at key developmental stages.

But they have also led to some experts warning against labelling children with serious disorders too early and pathologising some normal behaviours.

Lead researcher Dr Karen Wynter said while the results had to be cautiously interpreted, the findings from the Monash University-led study were “alarming”.

“I think mental health disorders are more prevalent in preschool-aged children than many people realise, and it’s a significant public health issue as for many children these disorders will persist into middle childhood, adolescence and adulthood,” she said.

The study, which screened 545 children aged three and four against the Preschool Age Psychiatric Assessment, revealed diagnoses including anxiety, separation anxiety, depression, conduct disorder and panic attacks, alongside ADHD and oppositional defiant disorder.

It found 47.9 per cent of preschoolers had a mental health diagnosis, with 21 per cent having more than one.

For example, all children with depressive disorder and 75 per cent of those with conduct disorder (aggressive and disobedient behaviour) also had anxiety.

A range of phobias such as being scared of the dark and spiders was also diagnosed, though Dr Wynter said some level of such behaviour was normal at a young age.

However, she said even when excluding the phobias and accounting for the sample having 17 per cent of mums who had depression during pregnancy, compared with a community average of about 12 per cent, almost a third of preschoolers still had serious mental illness.

“It’s still an alarming number of children,” she said, pointing out that for mothers with depression, this did not automatically mean their children would have mental health disorders.

“The sample shows that the prevalence of mental health disorders and comorbidities in three to four-year-old children is relatively high.

“I think comorbidity is more common than we think, but difficult to assess, diagnose and treat.”

Psychologist Dr Clare Rowe said while diagnosis at preschool age was sometimes helpful, it was important not to confuse normal developmental fears, dependency and emotional volatility with psychiatric disorder.

“The clinical question is whether those behaviours are persistent, severe, impairing and clearly outside what we would expect developmentally,” she said.

“Parents should not panic if their young child is scared of the dark, wary of separation or temperamentally sensitive.

“What matters is pattern, severity and impact. If distress is intense, ongoing, interfering with sleep, play, preschool attendance or family life, then it is worth seeking a proper developmental assessment.”

The study findings resonate with Melbourne mother of four Melanie, with two of her children – now aged 14 and 15 – first showing signs of anxiety and depression aged just four.

“It’s easy for people to distrust it and say, ‘They’re too young, it’s not real,’” she said. “Honestly, take your rose coloured glasses off.”

Melanie said as preschoolers, her daughter would have panic attacks and complain of a “sore chest”, while her son used to “worry about everything”, preventing him from sleeping.

Dr Wynter, who is based at Deakin University, said a mental health screener should be introduced for preschoolers, with holistic intervention prior to children starting school.

“Currently, we have long waiting lists for pediatric psychologists and psychiatrists,” Dr Wynter said.

“This is unacceptable – every family with a child with a mental health disorder should have access to timely, affordable, local assessment and treatment.”

Melanie “110 per cent” backed Dr Wynter’s call.

“The mental health system is so, so broken,” she said.