With this year's school ball season approaching, young people are being encouraged to be careful when drinking alcohol.
"Evidence shows that drinking alcohol at a young age can cause harm to the developing brain because a person's brain is still developing until the age of 25," Whanganui District Health Board health promotion officer Chester Penaflor said.
"Drinking alcohol at this age may result in developing learning difficulties, memory problems, mental health issues and other problems later in life such as alcohol abuse and alcohol dependency problems."
Mr Penaflor supported the national Health Promotion Agency's message that the safest option for people under 18 was to not drink.
The message is also endorsed by the Cancer Society, which says evidence shows alcohol use can cause cancer.