"I had to work five to six times as hard just to understand something ... and I never knew why.
"I did medicate myself for a short time [when diagnosed] but didn't really find any big results because I think ... you learn to deal with it."
Nationally, prescriptions jumped by nearly 40 per cent in the last six years - from 77,800 in 2006 to 107,400 in 2011. Prescription numbers jumped about 50 per cent in Northland and Wairarapa during the same period.
The disorder is defined by the Ministry of Health as a behavioural condition. Sufferers often have problems with concentration, impulsivity and over-activity.
New Zealand's ADHD Association says the increase in prescriptions probably reflects a greater awareness of the disorder.
"Traditionally, they thought [the disorder] was something that teenage boys have," national co-ordinator Marceline Borren said.
"Now it's known that it is neurological, it's quite genetic ... [and] 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 the disorder.
"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 medication for the disorder had increased by nearly 40 per cent since 2009. Last year 4060 patients were being treated for the disorder in this age group, compared with 2960 in 2009.
Adolescent patients, aged 10 to 19 years, made up the bulk of medication recipients.
In 2011, 53 per cent of all patients using medication for the disorder were in this age group. Figures also showed 30 children aged 4 years or younger were on the medication.
Ms Borren said children benefited 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.
Parents were also able to learn how best to manage a child with the disorder, she said.
"You do have to deal with them quite differently than your run-of-the-mill child.
"They should look definitely at their diet and nutritional status," Ms Borren said.
"And we highly recommend exercise."
ADHD specialist Dr Tony Hanne said it was likely many people were living with the disorder and had no idea.
"One in 20 people have [the disorder], which would be 200,000 people in the country."
He did not believe the medication was over-prescribed.
