A series of high-profile cases have highlighted the problem of drugs at secondary schools in the Inverness area in recent years.
A 19-year-old admitted selling cannabis to pupils at the gates of Millburn Academy last year.
Three 15-year-old girls smoked the drug in the grounds of the school, with one requiring hospital treatment after falling off her seat and hitting her head on the floor.
At Inverness Royal Academy, four pupils were excluded last year after police received a tip-off that pupils were smoking cannabis in nearby woods during the morning interval.
In 2014 a teenager admitted culpable and reckless conduct outside Charleston Academy the previous year after supplying herbal substances called Sensa and Legal Genesis to three pupils aged 13, 14 and 15 years.
The trio smoked them, making them ill, and it resulted in them being admitted to Raigmore Hospital.
In 2008 it was reported that police had made 11 drug recoveries in Highland schools the previous year, with six at Charleston Academy and three at Nairn Academy.