Teachers could often monitor the child for other problems in the classroom.
Concerned parents should see their GP, Dr Eggleton said.
"The child or whoever has got ADHD is referred on to a psychiatrist."
After an assessment and diagnosis, a treatment path is decided on, he said.
Dr Eggleton said those on medication were monitored for any changes in weight and growth, which were sometimes affected by ADHD drugs.
"[The] good majority of children benefit from the medication."
Nationally, prescriptions have jumped by nearly 40 per cent in the last six years - from 77,800 in 2006 to 107,400 in 2011.
Prescription numbers for the behavioural condition have jumped by about 50 per cent in Wairarapa and 35 per cent in the Hawkes Bay during the same period.
New Zealand's ADHD Association says traditionally the condition was believed to be something that teenage boys had.
National co-ordinator Marceline Borren said it's now known that it is neurological,
"It's quite genetic ... it's something that you learn to manage."
Ms Borren said there had also been a recent increase in the number of adults diagnosed with ADHD.
"Probably a third of our calls are from adults who have been recently diagnosed or suspect they have ADHD.
"Having come to it as an adult, they feel they have wasted all those years not knowing," she said.
Pharmac figures show the number of patients aged over-20 being prescribed ADHD medication has increased by nearly 40 per cent since 2009. But adolescent patients, aged 10 to 19 years, made up the bulk of medication recipients.
Ms Borren said children benefited most if the disorder was picked up in their early years.
"If it's left undiagnosed people tend to fail at things they try.
"They end up with all sorts of issues with anxieties, depression [and] total lack of self-esteem," she said.